Sesame: the genus Sesamum 9781420005202, 1420005200

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Sesame The genus Sesamum

Medicinal and Aromatic Plants — Industrial Profiles Individual volumes in this series provide both industry and academia with in-depth coverage of one major genus of industrial importance.

Series Edited by Dr. Roland Hardman Volume 1 Valerian, edited by Peter J. Houghton Volume 2 Perilla, edited by He-ci Yu,   Kenichi Kosuna and Megumi Haga Volume 3 Poppy, edited by Jenö Bernáth Volume 4 Cannabis, edited by David T. Brown Volume 5 Neem, edited by H.S. Puri Volume 6 Ergot, edited by Vladimír Kˇren and   Ladislav Cvak Volume 7 Caraway, edited by Éva Németh Volume 8 Saffron, edited by Moshe Negbi Volume 9 Tea Tree, edited by Ian Southwell and   Robert Lowe Volume 10 Basil, edited by Raimo Hiltunen and   Yvonne Holm Volume 11 Fenugreek, edited by   Georgios Petropoulos Volume 12 Ginkgo biloba, edited by   Teris A. Van Beek Volume 13 Black Pepper, edited by P.N. Ravindran Volume 14 Sage, edited by Spiridon E. Kintzios Volume 15 Ginseng, edited by W.E. Court

Volume 16 Mistletoe, edited by Arndt Büssing Volume 17 Tea, edited by Yong-su Zhen Volume 18 Artemisia, edited by Colin W. Wright Volume 19 Stevia, edited by A. Douglas Kinghorn Volume 20 Vetiveria, edited by Massimo Maffei Volume 21 Narcissus and Daffodil, edited by   Gordon R. Hanks Volume 22 Eucalyptus, edited by John J.W. Coppen Volume 23 Pueraria, edited by Wing Ming Keung Volume 24 Thyme, edited by E. Stahl-Biskup and   F. Sáez Volume 25 Oregano, edited by Spiridon E. Kintzios Volume 26 Citrus, edited by Giovanni Dugo and   Angelo Di Giacomo Volume 27 Geranium and Pelargonium, edited by   Maria Lis-Balchin Volume 28 Magnolia, edited by Satyajit D. Sarker and Yuji Maruyama Volume 29 Lavender, edited by Maria Lis-Balchin Volume 30 Cardamom, edited by P.N. Ravindran and K.J. Madhusoodanan

Volume 31 Hypericum, edited by Edzard Ernst Volume 32 Taxus, edited by H. Itokawa and   K.H. Lee Volume 33 Capsicum, edited by Amit Krish De Volume 34 Flax, edited by Alister Muir and   Niel Westcott Volume 35 Urtica, edited by Gulsel Kavalali Volume 36 Cinnamon and Cassia, edited by   P.N. Ravindran, K. Nirmal Babu   and M. Shylaja Volume 37 Kava, edited by Yadhu N. Singh Volume 38 Aloes, edited by Tom Reynolds Volume 39 Echinacea, edited by   Sandra Carol Miller   Assistant Editor: He-ci Yu Volume 40 Illicium, Pimpinella and Foeniculum,      edited by Manuel Miró Jodral Volume 41 Ginger, edited by P.N. Ravindran   and K. Nirmal Babu Volume 42 Chamomile: Industrial Profiles,   edited by Rolf Franke and   Heinz Schilcher Volume 43 Pomegranates: Ancient Roots to   Modern Medicine, edited by   Navindra P. Seeram,   Risa N. Schulman and David Heber

Volume 44 Mint, edited by Brian M. Lawrence Volume 45 Turmeric, edited by P. N. Ravindran,   K. Nirmal Babu, and K. Sivaraman Volume 46 Essential Oil-Bearing Grasses, edited by Anand Akhila Volume 47 Vanilla, edited by Eric Odoux   and Michel Grisoni Volume 48 Sesame, edited by Dorothea Bedigian

Sesame The genus Sesamum

Edited by

Dorothea Bedigian

Medicinal and Aromatic Plants — Industrial Profiles

CRC Press Taylor & Francis Group 6000 Broken Sound Parkway NW, Suite 300 Boca Raton, FL 33487-2742 © 2010 by Taylor & Francis Group, LLC CRC Press is an imprint of Taylor & Francis Group, an Informa business No claim to original U.S. Government works Version Date: 20140514 International Standard Book Number-13: 978-1-4200-0520-2 (eBook - PDF) This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. The authors and publishers have attempted to trace the copyright holders of all material reproduced in this publication and apologize to copyright holders if permission to publish in this form has not been obtained. If any copyright material has not been acknowledged please write and let us know so we may rectify in any future reprint. Except as permitted under U.S. Copyright Law, no part of this book may be reprinted, reproduced, transmitted, or utilized in any form by any electronic, mechanical, or other means, now known or hereafter invented, including photocopying, microfilming, and recording, or in any information storage or retrieval system, without written permission from the publishers. For permission to photocopy or use material electronically from this work, please access www.copyright.com (http:// www.copyright.com/) or contact the Copyright Clearance Center, Inc. (CCC), 222 Rosewood Drive, Danvers, MA 01923, 978-750-8400. CCC is a not-for-profit organization that provides licenses and registration for a variety of users. For organizations that have been granted a photocopy license by the CCC, a separate system of payment has been arranged. Trademark Notice: Product or corporate names may be trademarks or registered trademarks, and are used only for identification and explanation without intent to infringe. Visit the Taylor & Francis Web site at http://www.taylorandfrancis.com and the CRC Press Web site at http://www.crcpress.com

Contents Foreword............................................................................................................................................xi Preface to the Series........................................................................................................................ xiii Preface.............................................................................................................................................. xv Acknowledgments...........................................................................................................................xvii The Editor........................................................................................................................................xix Contributors.....................................................................................................................................xxi Chapter 1 Introduction: History of the Cultivation and Use of Sesame........................................1 Dorothea Bedigian Chapter 2 Cultivated Sesame and Wild Relatives in the Genus Sesamum L.............................. 33 Dorothea Bedigian Chapter 3 Chemical Studies on the Lignans and Other Minor Constituents of Sesame Seed Oil....................................................................................................................... 79 Afaf Kamal-Eldin Chapter 4 Sesame Seed Coat: A Rich Source of Potential Mammalian Lignan Precursors....... 93 Raphael Grougnet, Prokopios Magiatis, Sofia Mitakou, and Alexios-Leandros Skaltsounis Chapter 5 Antioxidant and Anti-Carcinogenic Potentials of Sesame Lignans.......................... 111 Duncan H.F. Mak, Po Yee Chiu, and Kam Ming Ko Chapter 6 Sesame Seed and Its Lignans: Metabolism and Bioactivities................................... 123 Sandra M. Sacco and Lilian U. Thompson Chapter 7 Physiological Effects of Sesame: Bioactive and Antioxidant Compounds............... 139 Fereidoon Shahidi and Zhuliang Tan Chapter 8 Sesame Seed Food Allergy....................................................................................... 155 Suzanne S. Teuber Chapter 9 Flavor Constituents of Sesame.................................................................................. 169 Fereidoon Shahidi, Tara Hughes, and Zhuliang Tan

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Chapter 10 Seed Oil Bodies of Sesame and Their Surface Proteins: Oleosin, Caleosin, and Steroleosin.......................................................................................................... 187 Jason T.C. Tzen Chapter 11 Use of Near-Infrared Reflectance Spectroscopy for Nondestructive Analyses of Sesame.................................................................................................................. 201 Tetsuo Sato, Aye Aye Maw, and Masumi Katsuta Chapter 12 Sesame’s Protective Role in Crop Nematode Control............................................... 211 Gamal Abdalla Elbadri and Abdelmageed Mohammad Yassin Chapter 13 Molecular Biotechnology of Sesame........................................................................ 219 Mi Chung Suh, Nam-In Hyung, and Chung-Han Chung Chapter 14 Responses of Sesame to Plant Growth Regulators, Micronutrients, and Salinity............................................................................................................... 245 M. Prakash Chapter 15 Seed Genetics in Relation to Yield in Sesame.......................................................... 255 S. Thirugnana Kumar Chapter 16 Sesame Diseases and Their Management................................................................. 267 P. Narayanasamy Chapter 17 Sesame Cultivation and Use in China....................................................................... 283 Zhao Yingzhong Chapter 18 Sesame Cultivation and Use in Ethiopia................................................................... 297 Adefris Teklewold, Tadele Amde, and Tesfaye M. Baye Chapter 19 Sesame Cultivation and Use in Iran.......................................................................... 321 S.M. Mahdi Mortazavian and J.A. Kohpayegani Chapter 20 Sesame Cultivation and Use in Somalia................................................................... 329 Ahmed Yakub Sidow Chapter 21 Sesame Cultivation and Use in Thailand.................................................................. 339 Wasana Wongyai

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Chapter 22 Sesame Cultivation and Use in Turkey..................................................................... 349 Bülent Uzun Chapter 23 History of Sesame Cultivation and Irrigation in the Armenian Highlands from the Kingdom of Urartu (Ararat) through Subsequent Periods: Major Agricultural Innovation............................................................................................. 367 Dorothea Bedigian Chapter 24 Introduction and Early Use of Sesame in America: Medicine, Cookery, and Folkways............................................................................................................. 389 Dorothea Bedigian Chapter 25 Current Market Trends: Critical Issues and Economic Importance of Sesame........ 423 Dorothea Bedigian Chapter 26 Current Regulatory Status of Sesame and Its Commercial Products....................... 491 Dorothea Bedigian Index...............................................................................................................................................507

Foreword “Open Sesame!”—This book will open your eyes to a wonderful, but mysterious, plant that has had many uses throughout human agricultural history. Dorothea Bedigian has devoted her professional life to the study and exploration of sesame and its progenitor and other plant relatives. This book draws on her extensive experiences and on those of a significant number of specialists from around the “sesame world.” Contrary to the mythology of Ali Baba, you will find many gems of knowledge, but will have the password to exit the treatise with those gems of your choice. Bedigian takes us through the somewhat muddied information about the origin of sesame and leads us to the most up-to-date information about how sesame became a cultivated plant since early days of agriculture. She has convincingly shown that it is now clear that sesame, Sesamum indicum L., originated in India and made its way as a passenger on human travels throughout the Asian and African centers of agriculture. Most of us do not know of the many uses of the seed of sesame in human diets as a source of protein, for flavor enhancement in many prepared foods, for the fine quality of cooking oil extracted from its seeds, its presumed and actual health benefits, its oil as a fuel, and many other uses that you will learn about. This book is especially timely because of interests in diversifying agriculture, meeting current and future global food shortages, and sesame’s emerging role in therapeutic and preventive medicine. With the wide adaptation of sesame to many climatic and edaphic situations, it may have a role in adapting to global climate changes. Sesame is not a mainstream crop in global agriculture, being cultivated on about 7 million hectares, but it is grown in all agricultural zones, mostly by farmers who have limited land and economic resources. It suits such farmers because it has not been modified to suit mechanized agriculture, although plant breeders, agronomists, and engineers are actively working on agricultural systems for producing high-quality seeds in large-scale fields. Thus, much hand labor is required for the culture of sesame. However, there are efforts to expand cultivation using new varieties, requiring genetic modification of the plant morphology and growth cycle that will make them more useful for mechanized harvesting. Sesame is regarded as a “neglected’,” “orphan,” or “underutilized” crop. These monikers are unfortunate in the sense that sesame is a vital element of small-scale farming systems, but at the same time these classifications call attention to this remarkable plant and might focus more attention on sesamein agricultural research and development circles. This book brings together scattered information on all aspects of sesame as a biological species, its origin, cultivation, and uses. The range of topics will satisfy the needs for general interest in a crop plant, while the depth of treatment in many chapters will serve the needs of specialists. Dr. Bedigian’s special interests in evolutionary biology, plant systematics, ethnobotany, and anthropology are evident in chapters that she carefully researched and published here for the first time. She extracted information from sources published in many languages and references research reaching far beyond the usual, readily available sources. On several topics she corrects misinformation that has been circulated in the literature for decades. As examples, especially unique contributions are her historical review detailing how sesame arrived in the Americas, in a truly trans-disciplinary style, and a rare look at sesame beyond the borders of Mesopotamia to the Armenian Highlands— introducing readers to a little-known history. This book is not just another collection of chapters compiled by specialists—it has new information from little-referenced sources, remarkable scope, and the editor’s personal touch for relevance and accuracy. At the same time, the reader will get the feel for how this plant is grown and used in a well-chosen sample of countries.

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Dr. Bedigian was the last student of Professor Jack R. Harlan; this work is a tribute to the scholarship that he expected of himself and his students and demonstrated by his own remarkable studies of many plants and people in many countries. I hope you will enjoy reading the many chapters as much as I have in preparing these comments. Calvin O. Qualset Professor Emeritus University of California, Davis

Preface to the Series There is increasing interest in industry, academia, and the health sciences in medicinal and aromatic plants. In passing from plant production to the eventual product used by the public, many sciences are involved. This series brings together information that is currently scattered through an everincreasing number of journals. Each volume gives an in-depth look at one plant genus about which an area specialist has assembled information ranging from the production of the plant to market trends and quality control. Many industries are involved, such as forestry, agriculture, chemical, food, flavor, beverage, pharmaceutical, cosmetic, and fragrance. The plant raw materials are roots, rhizomes, bulbs, leaves, stems, barks, wood, flowers, fruits, and seeds. These yield gums, resins, essential (volatile) oils, fixed oils, waxes, juices, extracts, and spices for medicinal and aromatic purposes. All these commodities are traded worldwide. A dealer’s market report for an item may say “drought in the country of origin has forced up prices.” Natural products do not mean safe products, and account of this has to be taken by the above industries, which are subject to regulation. For example, a number of plants that are approved for use in medicine must not be used in cosmetic products. The assessment of “safe to use” starts with the harvested plant material, which has to comply with an official monograph. This may require absence of, or prescribed limits of, radioactive material, heavy metals, aflatoxin, and pesticide residue, as well as the required level of active principle. This analytical control is costly and tends to exclude small batches of plant material. Large-scale, contracted, mechanized cultivation with designated seed or plantlets is now preferable. Today, plant selection is not only for the yield of active principle, but for the plant’s ability to overcome disease, climatic stress, and the hazards caused by mankind. Such methods as in vitro fertilization, meristem cultures, and somatic embryogenesis are used. The transfer of sections of DNA is giving rise to controversy in the case of some end uses of the plant material. Some suppliers of plant raw material are now able to certify that they are supplying organically farmed medicinal plants, herbs, and spices. The Economic Union directive CVO/EU No. 2092/91 details the specifications for the obligatory quality controls to be carried out at all stages of production and processing of organic products. Fascinating plant folklore and ethnopharmacology lead to medicinal potential. Examples are the muscle relaxants based on the arrow poison curare from species of Chondrodendron, and the antimalarials derived from species of Cinchona and Artemisia. The methods of detection of pharmacological activity have become increasingly reliable and specific, frequently involving enzymes in bioassays and avoiding the use of laboratory animals. By using bioassay-linked fractionation of crude plant juices or extracts, compounds can be specifically targeted that, for example, inhibit blood platelet aggregation, or have antitumor, antiviral, or any other required activity. With the assistance of robotic devices, all the members of a genus may be readily screened. However, the plant material must be fully authenticated by a specialist. The medicinal traditions of ancient civilizations such as those of China and India have a large armamentarium of plants in their pharmacopoeias that are used throughout Southeast Asia. A similar situation exists in Africa and South America. Thus, a very high percentage of the world’s population relies on medicinal and aromatic plants for their medicine. Western medicine is also responding. Already in Germany all medical practitioners have to pass an examination in phytotherapy before being allowed to practice. It is noticeable that medical, pharmacy, and health-related schools throughout Europe and the United States are increasingly offering training in phytotherapy. Multinational pharmaceutical companies have become less enamored of the single-compound, xiii

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magic-bullet cure. The high costs of such ventures and the endless competition from “me-too” compounds from rival companies often discourage the attempt. Independent phytomedicine companies have been very strong in Germany. However, by the end of 1995, 11 (almost all) had been acquired by the multinational pharmaceutical firms, acknowledging the lay public’s growing demand for phytomedicines in the Western world. The business of dietary supplements in the Western world has expanded from the health store to the pharmacy. Alternative medicine includes plant-based products. Appropriate measures to ensure their quality, safety, and efficacy either already exist or are being answered by greater legislative control by such bodies as the U.S. Food and Drug Administration and the recently created European Agency for the Evaluation of Medicinal Products, based in London. In the United States, the Dietary Supplement and Health Education Act of 1994 recognized the class of phytotherapeutic agents derived from medicinal and aromatic plants. Furthermore, under public pressure, the U.S. Congress set up an Office of Alternative Medicine, which in 1994 assisted the filing of several Investigational New Drug (IND) applications required for clinical trials of some Chinese herbal preparations. The significance of these applications was that each Chinese preparation involved several plants and yet was handled as a single IND. A demonstration of the contribution to efficacy of each ingredient of each plant was not required. This was a major step toward more sensible regulations in regard to phytomedicines. There have been two recent very important developments in Sesamum research: The development of a cultivar of Sesamum with ripe nonshattering seed pods permitting, for the first time, the mechanical harvesting of this crop instead of labor intensive selection of ripe pods from a field of pods in varying degrees of ripeness. This discovery has arisen in Thailand due to a shortage of labor (Anonymous)—a development which has moved this crop into the twenty-first century. At last there is the future opportunity to meet world demand on the oil seed market. The second notable development is elucidated in the paper “HPTLC Fingerprinting and Quantification of Lignans [sesamin and sesamolin] as Markers in Sesame Oil and Its Polyherbal Formulations,” by Divya Sukumar et al. in the Journal of Pharmaceutical and Biomedical Analysis 2008, 47 (4/5): 795–801. For this volume I thank its editor, Dr. Dorothea Bedigian, for her dedicated hard work and its chapter contributors for their authoritative information (if there are other contributors I thank those as well). My thanks are due also to Barbara Norwitz of CRC Press and her staff for their unfailing help. Roland Hardman BPharm, BSc (Chem), PhD (London), FR Pharm S

Preface Sesame is an herbaceous annual plant cultivated for its flavorsome, edible seed. Grown since antiquity on the Indian subcontinent and throughout Mesopotamia and Eastern Anatolia, sesame spread to China by the 2nd century BCE. Today, China is the world’s largest consumer and one of its primary producers. Sesame has a long history of traditional use as food, medicine, and lamp oil for illumination. Known also as gingelly, til, and benne seed, it is popularly hailed as the “Queen of Oilseeds,” and edible use is made of the leaves too, particularly in China and Korea. Sesame harvest is relatively labor intensive, hence, despite its popularity and nutritional advantages, it is little cultivated where labor costs are high. Sesame seeds have an appealing, nutty taste, and crushed seeds yield aromatic edible oil and creamy paste. Sesame seed is rich in oil (ca. 50%), containing high levels of unsaturated fatty acids, primarily oleic and linoleic; protein (ca. 25%), including the especially significant limiting amino acid methionine; and dietary fiber and nutrients, including minerals, lignans, tocopherol, and phytosterol. These compounds exert various health benefits: they confer outstanding resistance to oxidation and cancer, and depress blood pressure and cholesterol levels. Conversely, sesame seeds are allergenic and can cause adverse effects in susceptible individuals. The primary focus of this book is on the medicinal and aromatic constituents of sesame. Traditional medicinal uses and historical documents, as well as the latest laboratory studies, are included. Since the mid-1980s, there has been a steadily growing interest in the medicinal and nutraceutical value of sesame. Research has concentrated on the biological activity of lignans, in particular their antioxidant value and the role of sesame lignans in health. The secondary focus of this book is on cultivation practices and the history of the traditional and medicinal uses of sesame seeds, with a compilation of the diverse applications humans have found for this crop. The diseases and insect pests encountered by sesame growers, along with the preferred strategies for their control, are also described. Fortunately, its commercial success has increased, and sesame is cultivated in many countries around the world. Accounts from some of the pivotal growing areas for sesame with descriptions of agronomic practices typical for sesame production in each region are included, written by a set of experts from China, Ethiopia, India, Iran, Somalia, Thailand, and Turkey, who provide a comprehensive and thorough portrait of the sesame plant from their unique perspectives, covering crop husbandry from planting to ripening, harvest, and post-harvest operations, genetics, physiology, pests, and remedies. These scientists, from a multitude of nations, provide their distinctive views by way of research reports for readers of English rendered from their native languages—Amharic, Arabic, Armenian, Chinese, Farsi, Somali, Thai, and Turkish—opening wide a window on regional practices. This book gives readers a comprehensive overview of the present knowledge of sesame and its many uses, both old and new, the wide range of biological activities associated with its constituents, and its production. A historical perspective shows the ancient impact of sesame on the Iron Age economy of Urartu in the Armenian highlands and plains surrounding Lake Van. The pathway sesame took to reach the Americas from Africa is provided through a review of scarce sources from the time of the African slave trade. Readers will discover that the commercial market in sesame and its oil has been dramatically revitalized this year. A review of the current regulatory status and risks of sesame products for human consumption completes the volume. It is my fervent hope that these reports will give momentum to sesame research, and serve as a call to action, inspire dialogue, and increase collaborative research. Sesame still holds many secrets that we’ve just begun to unlock. The treasure lies within: Open Sesame! Dorothea Bedigian xv

Acknowledgments Many have assisted in this project. I thank the editors of the publisher and the Medicinal and Aromatic Plants series editor for the opportunity to create a volume about sesame, and for the continuous support and prompt advice throughout its preparation. I express thanks to the authors for their essential contributions and their efforts in generating an up-to-date volume of high standards. I am grateful for the encouragement of various individuals and for their support of these wide-ranging investigations of sesame with their helpful suggestions, and on behalf of the authors, I express thanks to those who reviewed articles for this volume and by doing so helped to improve the quality of the contributions, namely Edward J. Kennelly, associate professor of biology, Lehman College, Bronx, New York; L.J.G. van der Maesen, professor of plant taxonomy, Biosystematics Group and National Herbarium of the Netherlands, Wageningen University, Wageningen, the Netherlands; Mahmoud A. Mahmoud, agronomist, Wad Medani and Khartoum, Sudan; Peter H. Raven, president, Missouri Botanical Garden; David S. Seigler, professor of botany, University of Illinois, Urbana-Champaign; Richard C. Staples, G.L. McNew Scientist Emeritus, Boyce Thompson Institute for Plant Research, Cornell University, Ithaca, New York. This work received indispensable support from a host of librarians at several institutions. Deepest gratitude for their enduring welcome goes to Olive Kettering Library, Antioch College, Yellow Springs, Ohio; Leonard Lief Library, Lehman College, City University of New York; Missouri Botanical Garden, St. Louis; Resource Sharing, Greene Country Public Library, Xenia, Ohio; and Yvette Scheven, Africana Bibliographer, University of Illinois, Urbana-Champaign. Dorothea Bedigian

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The Editor Dorothea Bedigian is an ethnobotanist who through interdisciplinary research investigates aspects of Sesamum biogeography, botany, chemistry, cultivation, and harvest practices, genetic resources, ancient and recent history in Africa and Asia, names in many languages, and its cultural impacts, indicated by its worldwide use. She is a research associate at the Missouri Botanical Garden, St. Louis. Born in New York City, Bedigian received early exposure to diverse branches of botany and its scholarship working in the library and research laboratories of the New York Botanical Garden. After receiving her Bachelor’s degree, she conducted independent research at the Boyce Thompson Institute for Plant Research, Yonkers, New York. This encouraged further botanical research during graduate study at the University of Vermont, Burlington. Advanced coursework at Harvard University and graduate study at the University of Illinois, Urbana-Champaign, where she obtained her Ph.D. in agronomy, presented opportunities to explore their magnificent research libraries. The present undertaking derives from an interest in the material cultures of Africa, ancient Mesopotamia, and the Armenian Highlands. Bedigian was inspired to study sesame after translating an archaeological site report from its original Armenian language. It describes a 60-room workshop for pressing oil from sesame seeds at the hilltop Iron Age (900–600 BC) Urartian site Karmir Blur, flanking Yerevan, Armenia. Fluency with the Armenian language and a profound interest in its history opened sesame for her. That strong bond, united with a love for the Sudan, where she was an International Voluntary Services teacher in the ancient city of Omdurman, initiated explorations of Sudan’s astonishing sesame cultivar diversity, its wild relatives, and agricultural practices among peoples having prominent sesame-based agriculture. Those studies have taken place in India, Kenya, Mali, Namibia, Syria, Tanzania, Uganda, and Yemen. The regions selected were some of the most impoverished and least explored: a result of extreme environmental conditions, political neglect, instability, and war. Surveys in each of Sudan’s Darfur provinces and travel to Acholi-populated villages and Sudanese refugee camps in northern Uganda were with the intent to learn about cultivars once grown in desolated neighboring southern Sudan, and enabled comparison with earlier observations in the Nuba Mountains. Assessment in villages of Wadi Hadhramaut, Yemen, enabled study of sesame cultivars and traditional agricultural practices and comparison with customs along Syria’s southern Euphrates. Field study in Namibia increased her appreciation of the genus Sesamum and the Pedaliaceae, in sharp contrast with species in locations north of the Equator. She observed the progenitor of sesame growing wild in a number of diverse habitats in India, in natural forest as well as in waste places. Interests at the intersection of botany with culture elicited a profound concern for the underclass: the exploited, forgotten, ignored, neglected and rejected; people of courage, stamina and strength; the central motivators of this work.

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Contributors Tadele Amde Ethiopian Institute of Agricultural Research Melka Worer Research Center Addis Ababa, Ethiopia Email: [email protected] Tesfaye M. Baye Department of Pediatrics University of Cincinnati Cincinnati Children’s Medical Center Cincinnati, Ohio Email: [email protected] Dorothea Bedigian Missouri Botanical Garden St. Louis, Missouri Email: [email protected] Po Yee Chiu Department of Biochemistry The Hong Kong University of Science and Technology Hong Kong, China Email: [email protected]

Tara Hughes Department of Biochemistry Memorial University of Newfoundland St John’s, Newfoundland, Canada Nam-In Hyung Department of Plant Science and Technology Sangmyung University Cheonan, South Korea E-mail: [email protected] Afaf Kamal-Eldin Department of Food Science Swedish University of Agricultural Science Uppsala, Sweden Email: [email protected] Masumi Katsuta National Institute of Crop Science (NICS), NARO Tsukuba, Ibaraki, Japan Email: [email protected]

Chung-Han Chung Department of Biotechnology Dong-A University Busan, South Korea Email: [email protected]

Kam Ming Ko Department of Biochemistry The Hong Kong University of Science and Technology Hong Kong, China Email: [email protected]

Gamal Abdalla Elbadri Head of Plant Pathology Program Crop Protection Research Centre Agricultural Research and Technology Corporation Wad Medani, Sudan Email: [email protected]

J.A. Kohpayegani National Plant Gene Bank of Iran Seed and Plant Improvement Institute Karaj, Iran Email: [email protected]

Raphael Grougnet Laboratory of Pharmacognosy Faculté des Sciences Pharmaceutiques et Biologiques Paris, France Email: [email protected]

S. Thirugnana Kumar Department of Agricultural Botany Faculty of Agriculture Annamalai University Tamil Nadu, India Email: [email protected]; [email protected] xxi

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Prokopios Magiatis Department of Pharmacognosy and Natural Products Chemistry Faculty of Pharmacy University of Athens, Panepistimiopolis Zografou, Greece Email: [email protected] Duncan H.F. Mak Department of Biochemistry The Hong Kong University of Science and Technology Hong Kong, China Email: [email protected] Aye Aye Maw Central Agricultural Research Institute Yezin, Pyinmana, Myanmar Sofia Mitakou Department of Pharmacognosy and Natural Products Chemistry Faculty of Pharmacy University of Athens, Panepistimiopolis Zografou, Greece Email: [email protected] S.M. Mahdi Mortazavian Department of Agronomy and Plant Breeding College of Abouraihan Tehran University Tehran, Iran Email: [email protected] P. Narayanasamy Department of Plant Pathology Tamil Nadu Agricultural University Coimbatore, India Email: [email protected]/[email protected] M. Prakash Department of Agricultural Botany Faculty of Agriculture Annamalai University Chidambaram, India Email: [email protected]

Contributors

Sandra M. Sacco Department of Nutritional Sciences Faculty of Medicine University of Toronto Toronto, Ontario, Canada Email: [email protected] Tetsuo Sato National Agricultural Research Center for Kyushu Okinawa Region (KONARC) National Agriculture and Food Research Organization (NARO) Kumamoto, Japan Email: [email protected] Fereidoon Shahidi Department of Biochemistry Memorial University of Newfoundland St John’s, Newfoundland, Canada Email: [email protected] Ahmed Yakub Sidow Agronomist Somalia Email: [email protected] Alexios-Leandros Skaltsounis Department of Pharmacognosy and Natural Products Chemistry Faculty of Pharmacy University of Athens, Panepistimiopolis Zografou, Greece Email: [email protected] Mi Chung Suh Department of Plant Biotechnology and Agricultural Plant Stress Research Center Chonnam National University, South Korea Email: [email protected] Zhuliang Tan Department of Biochemistry Memorial University of Newfoundland St John’s, Newfoundland, Canada Email: [email protected]

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Adefris Teklewold Ethiopian Institute of Agricultural Research Holetta Research Center Addis Abeba, Ethiopia Email: [email protected] Suzanne S. Teuber Division of Rheumatology, Allergy & Clinical Immunology University of California, Davis, School of Medicine Davis, California Email: [email protected]

Bülent Uzun Department of Field Crops Faculty of Agriculture Akdeniz University Antalya, Turkey Email: [email protected] Wasana Wongyai Department of Agronomy Kasetsart University Bangkok, Thailand Email: [email protected]

Lilian U. Thompson Department of Nutritional Sciences Faculty of Medicine University of Toronto Toronto, Ontario, Canada Email: [email protected]

Abdelmageed Mohammad Yassin Ex. Professor in Agricultural Research Corporation Teacher in Khartoum, El Fasir, and Juba Universities Khartoum, Sudan Email: [email protected]

Jason T.C. Tzen Graduate Institute of Biotechnology National Chung-Hsing University Taichung, Taiwan Email: [email protected]

Zhao Yingzhong Oil Crops Research Institute Chinese Academy of Agricultural Sciences Wuhan, China Email: [email protected]

1 Introduction History of the Cultivation and Use of Sesame Dorothea Bedigian Contents Introduction.........................................................................................................................................2 Biological Origins...............................................................................................................................2 History of Sesame in the Ancient World: Contacts and Cultural Diffusion.......................................2 Bronze Age Mesopotamia: Excavated Seed...................................................................................4 Bronze Age Mesopotamia: Textual Evidence.....................................................................................4 Iron Age Eastern Anatolia..............................................................................................................5 New Discovery from Hellenistic Greece.......................................................................................5 Further East....................................................................................................................................6 Sesame Seed Constituents...................................................................................................................6 Nutritional Benefits.............................................................................................................................6 Edible Use...........................................................................................................................................7 Industrial Use......................................................................................................................................8 Medicinal Use.....................................................................................................................................8 Fiber Use.............................................................................................................................................9 Enfleurage—Use with Aromatic Extractions......................................................................................9 Agronomic Attributes and Genetic Diversity: Ecosystem Services to Adverse Landscapes..............9 Harvest.............................................................................................................................................. 10 Breeding............................................................................................................................................ 10 Etymology......................................................................................................................................... 13 Sesame for Luck and Protection against the Evil Eye...................................................................... 14 Sesame Motif in Art, Literature, Music, and Film............................................................................ 14 Sesame Oil Presses........................................................................................................................... 15 Sesame and Cultural Survival........................................................................................................... 22 Paradox of Sesame: “Queen of Oilseeds” Yet Orphan Crop.............................................................25 Acknowledgments.............................................................................................................................26 References.........................................................................................................................................26

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Sesame: The Genus Sesamum

SESAME PROEM “When the robbers had departed, Aly went to the door of the cave and pronounced the magic words he had heard them use, OPEN SESAME. The door opened and he went inside and the door closed behind him. So astonished was he at the sight of the treasures in the cave and so absorbed in contemplation of them that when at last he desired to leave the cave he had quite forgotten the formula OPEN SESAME. In vain, he cried aloud Open wheat, Open barley, Open maize, Open lentils; none of these availed and the door remained shut.” Arabian Nights Entertainment, as cited by the Sudan Department of Agriculture and Forests, and Department of Economics and Trade (1938)

Introduction We open this exploration of sesame (Sesamum indicum L.) using a millennium-old dictum that produced magical results: Open Sesame! Literally, the directive refers to the capsules of sesame that open readily by shattering, explosively releasing their seeds. The spell signifies free or unrestricted access, opening a door that was previously shut tight. The DK Illustrated Oxford Dictionary (1998) defines the incantation Open Sesame! as “a means of achieving what is normally unattainable.” We desire, as the poet Ted Hughes (1967) wrote, “to find the words that will unlock the doors of all those many mansions in the head and express something—perhaps not much, just something—of the crush of information that presses in on us.”

Biological Origins Since antiquity, sesame (Figure  1.1) has been a valued oil crop, the seeds storing roughly half their weight as oil, with nearly all the rest protein. Sesame seed found in an excavation at Harappa (Pakistan) is dated to circa 2000 BC. Writers often describe sesame as the oldest oilseed plant used by humans (Joshi 1961; Weiss 1971); Mabberley’s indispensable reference The Plant-Book (1997) states that it is “widely naturalized and long cultivated, the oldest grown oilseed, since ca. 3500–3050 BC in Indus and Ancient Mesopotamia.” In the literature, sesame’s origin has been a matter of discussion for more than a century among hundreds of writers. Many invoke domestication in Africa based on geographic affinities, an assertion widely stated, though never proven. On the other hand, our evidence shows domestication on the Indian subcontinent, based on the formation of fully fertile hybrids, RAPD analysis, and common lignan constituents. These data confirm the proximity between Sesamum indicum and the progenitor, named Sesamum orientale var. malabaricum Nar. by John et al. (1950). Interspecific crosses and chemical survey of lignan constituents (Bedigian 1984, 1988, 2000, 2003a; Bedigian et al. 1985), work by later groups who repeated the hybridizations (Annapurna Kishore Kumar 2003; Annapurna Kishore Kumar and Hiremath 2008; Hiremath and Patil 1999; Kawase 2000), and studies with RAPD markers by Bhat et al. (1999) and Nanthakumar et al. (2000) emphatically demonstrate the proximity between S. indicum and its progenitor. They also have the same chromosome number: 2n = 26. Therefore, Sesamum indicum and the aforementioned var. malabaricum clearly belong in one biological species, and may be distinguished with subspecific ranks (Harlan and de Wet 1970). Said another way, united, they define the primary gene pool (Harlan 1992). Details continue in Bedigian, Chapter 2, this volume.

History of Sesame in the Ancient World: Contacts and Cultural Diffusion Preeminent prehistorian Colin Renfrew opens his early treatise “Trade and Culture Process in European Prehistory” (1969) with the declaration: “Trade is one of the activities of prehistoric man

Introduction

3

Figure 1.1  Sesamum indicum. (Reproduced with permission from Seegeler, С.J.P. 1983. Agricultural Research Reports, 921. Centre for Agricultural Pub. and Documentation, Wageningen, the Netherlands. Drawn by artist Juliet M. Beentje-Williamson.)

which has received much less attention than it deserves. In particular, sometimes crucial importance lies in a dual status: as the indicator for us today that intercultural contact was taking place, and as a prime motive, among prehistoric groups, for such contact.” The Atlas of Early Man (Hawkes 1976) labels the Iran-India region as vast during the period 5000–3000 BC, extending from India across the mountain steppes of the Taurus and Anti-Taurus ranges. The Levant and Mesopotamia, often dubbed the Fertile Crescent, led the way in mixed farming. Influenced by peoples from Mesopotamia, they eventually lost cultural leadership. The Mesopotamian dominion arose through highly productive irrigation and dry farming agriculture (Zettler 2003). The engine that drove these economies was agriculture, robust by the early Bronze Age. Hawkes viewed the millennium 3000–2000 BC as a period of high civilization. By 2600 BC, a powerful realm had arisen in the Indus Valley. There was mercantile trade on the Arabian Sea between Mohenjo Daro and Ur, as well as early overland trade between the Indus and Mesopotamia (Algaze 1993; Beale 1973; Kenoyer 1997; Mookerji 1912; Potts 1993; Ratnagar 1981; Reade 1979). During this time, there were fully developed Indus cities and ports. Excavations at the Indus site of Harappa (Vats 1940) uncovered a lump of burned and charred Sesamum. Vats’s material at Harappa came from levels of the Mature Harappan phase, dating from 2600/2500 to 2000 BC (Kenoyer

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Sesame: The Genus Sesamum

1991; Possehl 1997; Shaffer 1992). Additional contemporary evidence comes from the archaeobotanical study of the second half of the third millennium BC of the Harappan site at Miri Qalat, Makran, southwestern Pakistan (Tengberg 1999). Fuller’s review (2003) of the archaeological finds of sesame from 22 sites concludes that cultivated sesame was an established crop in northwestern South Asia by the time of the Harappan civilization and concurs with Bedigian that sesame had spread west to Mesopotamia before 2000 BC. Weber (1991) did not find sesame among the seeds at Rojdi, but he indicates (in his Table 10.1) that early sesame occurred in the “Indus Valley Core Area, Mature H” phase that he attributes to ca. 2600 BC, and that sesame was a summer crop. A relic of sesame’s Harappan antiquity was its name, tila, subsequently given to all kinds of oil (tel). Some writers have remarked on the paucity of sesame from archaeological sites. Recovery of sesame seeds from ancient sites is incomplete because charred sesame seeds do not preserve well. Unlike cereal and legume seeds, the slender testa encloses a large endosperm with high oil content. Charring resulting in fragmentation and collapse of testa walls, and seed structure disappears (Bedigian 2003b).

Bronze Age Mesopotamia: Excavated Seed Sesame reached Mesopotamia in the Early Bronze Age, not long after its domestication and expanded cultivation in Harappa. By 2000 BC, it was a crop of great importance. Mesopotamia became the main center of distribution of sesame into the Mediterranean. Sesame was a valuable cargo in the trade between India and the Mediterranean along the southern Arabian and Red Sea coasts in the second century BC. Sesame was present by the third millennium BC in Mesopotamia (Charles 1989), thus making the identification of sesame with “oil-plant” in Sumerian literature plausible (Bedigian 1985; Postgate 1985). Charles (1993, 1994) revisited ash tip plant remains from Abu Salabikh (excavated 1978) to find sesame seeds dated to the middle of the third millennium BC in Mesopotamia. Van Zeist (1994, 1999) reported that six damaged sesame seeds were recovered from a thirteenth-century-BC sample from Late Bronze Sabi Abyad (1550–1250 BC) Tell Balikh, northern Syria. Two contexts at Tell Schech Hamad, on the Khabur of northeastern Syria, yielded evidence of sesame; one seed was recovered from a thirteenth-century-BC sample and a few more from a seventh-century-BC context (van Zeist 2001).

Bronze Age Mesopotamia: Textual Evidence Cuneiform texts from 2400 BC onwards mention an oil plant, Akkadian šamaššammū; its decipherment was in dispute for many decades. Scholars are now convinced that it is sesame (Bedigian 1985, 1998, 2000, 2004a; Bedigian and Harlan 1986; Fuller 2003; Powell 1991; Zohary and Hopf 2000). Although the concluding view in the šamaššammū article prepared for the “Š” volume of the Chicago Assyrian Dictionary [CAD] (Reiner et al. 1989) was that the word should be translated “flax,” it nevertheless contains several texts that support the identification of šamaššammū as sesame. An Old Babylonian text concerned with processing the seed says: “It came to 90 gur of šamaššammū before it started raining. I managed to crush 40 gur of it and the rain did not arrive to ruin it” (Dossin 1933). Mesopotamia’s rainy season starts in autumn; therefore, the text clearly refers to a summer-grown crop harvested in fall. Linguistic evidence also suggests that sesame oil was among the Indus transfers to Mesopotamia (Bedigian 1984, 1985; Bedigian and Harlan 1986), as endorsed by Southworth (1995) and Witzel (1999). Known in Sumerian as ilu/ili and in Akkadian as ellu/ulu, the names are strikingly similar to early Dravidian names for sesame, el or ellu. Sesame exchange was by way of both overland and seafaring merchants into Mesopotamia by the middle of the Bronze Age (Bedigian 1998, 2000, 2004a). It became an indispensable part of their agricultural regime, grown as a summer crop (Columella 1941) that tolerated the hot and dry conditions of the steppes superbly.

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Although the Indus civilization collapsed in 1750 BC (Hawkes 1976), this was a time of advances in technology and transportation in Mesopotamia and Anatolia. Indo-Europeans moved into Iran by 2000–1500 BC; the Babylonian Empire was established in Mesopotamia; Hittites arrived in Anatolia, and the Mittani in northern Syria. Ancient trade links united India, Mesopotamia, Anatolia, and Africa (Algaze 1993). Sesame cultivation spread northward into Eastern Anatolia by the late Bronze Age, as Babylonia succeeded Sumer (Bedigian 1985, 2004a; Bedigian and Harlan 1986). Herodotus stressed that the only oil used by the Babylonians derived from sesame (Bedigian 1984, 1985, 1998, 2000, 2004a; Bedigian and Harlan 1986). By the middle of the second millennium, sesame seeds had reached Egypt, and have been found among the grave goods of King Tutankhamen (Bedigian 1998, 2000, 2004a; Vartavan 1990). Feldman (2006), writing about the late Bronze Age, supports such long-distance exchange, recording inter-dynastic marriages with Egypt as another example. Bedigian provides additional records of its introduction into Africa in Chapter 24 of this volume.

Iron Age Eastern Anatolia The Kingdom of Ararat—that name being a corruption of the Assyrian and Biblical Urartu (Piotrovskii 1969)—dominated eastern Anatolia from 900 to 600 BC, and during its three hundred years of existence the Urartian Empire was a formidable power with a flourishing economy. With the temporary eclipse of Assyria in the first half of the eighth century BC, Urartu became the largest and most powerful state in the Near East (Zimansky 1995). Urartu was the creation of a uniquely single-minded and consistent dynasty, bent upon developing Armenia’s agricultural potential and exploiting it mainly with captive labor (Zimansky 1985). Throughout its history, from its origins in the thirteenth century BC to its transformation into the Armenian nation by the sixth century BC (Chahin 2001), Urartu’s strategic location granted contact with many regions. On the outskirts of Yerevan, at the site of Karmir Blur, ancient Teishebaini, in the northern portion of the Urartian Empire, excavators under the direction of Boris Piotrovskii (1950, 1952, 1969) unearthed a large-scale manufacturing center devoted to processing sesame oil (Kassabian 1957) as an export commodity during the seventh century BC. Renfrew (1969) cautioned: “Trade cannot be assumed; it has to be proved.” Barnett (1959) described the site: “In addition to storerooms, a 3-room workshop for extracting sesame oil, finds of ornaments which included twelve large sard beads, about fifteen beads of grey glazed faience, others much damaged, of glass and sardonyx, a lignite tubular bead, another of faience, and a necklet, consisting of sixty-two cowrie shells,” the latter unambiguously indicative of long-distance exchange. Moreover, Barnett and Watson (1952) reported: “Scaraboids of Egyptian type have already been mentioned showing connections with Phoenician or Egyptian circles. In addition a small pendant of glazed paste representing Sekhmet was found.” Seed remains and a storeroom of pithoi containing sesame oil were uncovered; gutters or outlets carved in tufa, the soft volcanic rock of the region, eliminated waste water after processing (Kassabian 1957). Room 2 contained cakes of sesame and refuse of sesame oil (Barnett and Watson 1952). Sesame cultivation in these Urartian heartlands has continued for three millennia. Bedigian gives further details in Chapter 23 of this volume.

New Discovery from Hellenistic Greece Recently, large quantities of charred sesame seeds were recovered at the northern Greek excavation of Krania, in the area of Pieria, in Greek Macedonia. The site was a city house dating from the last quarter of the fourth century BC to the first quarter of the third century BC (Margaritis 2009). The charred mass of sesame seeds (fused and loose) number in the thousands and derives from a destruction layer of a so-called “tavern” and not a “normal” household. Other material from the same destruction layer includes pulses, cereals, fruits, pine nuts, and a lot of animal and fish bones and seashells, representing residues of meals.

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Sesame: The Genus Sesamum

Further East The eastward spread of sesame is little known, with no archaeobotanical discoveries yet. By the second century BC, it was a prominent oil crop in China. Our earliest evidence comes from textual references that date to the Han Dynasty, ca. 200 BC to AD 100, which united China in 206 BC, a dynasty characterized by an explosion of technological inventions and innovations, including many crop introductions, among them sesame. According to the classic ancient Chinese herbal and medical treatise Pen Ts’ao Kang Mu [Standard Inventory of Pharmacology] (1596) compiled mid-tenth century, sesame was brought from the west by General Chang Ch’ien during the Han Dynasty (second century BC), probably via the Silk Route. The name (tzuh-ma) indicates an overseas introduction. The Han Dynasty expansion opened China to non-Chinese things, including foods (Yü 1977). Yü says: “Sesame seems to have been particularly important, for it alone appears three times in the text. The kind of ‘barbarian grain food’ (hu-fan) enjoyed by Emperor Ling (AD 168–188) was in all likelihood grain food cooked with the flavorful sesame (Hou Han shu, chih 13: 8b)” and “Under the Later Han, a great variety of noodle foods were cooked, including boiled noodles, steamed buns (modern man-t’ou), and baked cakes with sesame seeds” (S.H. Ch’i 1949, cited in Yü 1977). In T’ang times there were extremely popular foreign cakes: “Particularly well-liked was a steamed variety containing sesame seeds … sold by foreign vendors—seemingly Iranians for the most part—on street corners” (Hsiang 1957, cited by Schafer 1977). Mote (1977) lists sesame-oil noodles among a group of sacrificial food offerings made to ancestors during the Ming Dynasty: “We can assume that they reveal the tastes and food ideals of the former poor peasant family which now found itself the imperial family, and that the foods offered were also those actually eaten in the imperial household.” Laufer (1919) reviews some confusion in the interpretation of the original name variously as sesame, flax, and hemp.

Sesame Seed Constituents Per 100 g edible portion, dry decorticated sesame seed contains water (3.8 g), energy (2640 kJ; 631 kcal), protein (20.5 g), fat (60.2 g), carbohydrate (11.7 g), dietary fiber (11.6 g), Ca (60 mg), Mg (345 mg), P (667 mg), Fe (6.4 mg), Zn (6.7 mg), vitamin A (9 IU), thiamin (0.70 mg), riboflavin (0.09 mg), niacin (5.80 mg), folate (115 μg), and no ascorbic acid (USDA 2005). The seed is rich in phytic and oxalic acids, which on chelating with calcium create a slightly bitter taste. Crude sesame oil varies from dark to pale yellow, while the refined oil is clear pale yellow; both have a nutty flavor. It contains glycerides of oleic acid (36–54%) and linoleic acid (38–49%); other components are saturated fatty acids: myristic acid (0.1% or less), palmitic acid (8–12%), stearic acid (3.5–7%), and arachidic acid (0.5–1%). The oil contains 1.2% unsaponifiable matter that includes tocopherols, and the lignans sesamin (0.1–0.6%), sesamolin (0.25–0.3%), sesamol, and sesaminol, which give the oil its resistance to oxidation. Extracted sesame cake varies in color from light yellow to grayish black, depending on the dominant seed coat color. Its chemical composition also varies according to cultivar, method of oil extraction, and presence of testae. The protein content of sesame cake ranges from 35% (expellerpressed, unhulled) to 47% (hexane-extracted, decorticated). The cake is rich in calcium and phosphate, but poor in lysine. Crude fiber content in cake from unhulled seed is 5–6%, but only about 3% in cake from hulled seed. The consumption of sesame products may cause an uncommon but serious food allergy. The main allergens are seed proteins. The allergy develops during adolescence in many cases, and is progressive. Teuber provides a discussion of sesame allergens in Chapter 8.

Nutritional Benefits Versatile sesame seeds are food, flavoring, and a source of prized oil. The fixed oil, extracted by pressure, and known in India as sesame, gingelly, or teel oil, is bland in taste and not highly

Introduction

7

aromatic. What is exceptional about sesame? The seeds are a source of high quality protein as well as oil (Bedigian 2000; Bedigian and Harlan 1983; Dirar 1993; Mkamilo and Bedigian 2007). Rich in polyunsaturated fats, its oil is remarkably stable because of its natural antioxidants sesamin and sesamolin, which are unique phenylpropanoid lignans that occur in few other plant groups (Bedigian 1984, 1988; 2003a; Bedigian et al. 1985). These lignans protect sesame oil from oxidative rancidity (Ikeda 2001; Kamal-Eldin 1993; Suja et al. 2004; Weiss 1971), a fact that might contribute to its reputation as a high quality oil among enthusiastic users worldwide, who award sesame the exalted label “Queen of the Oilseed Crops” (Al-Yemeni et al. 2000; Batra et al. 2001; Bedigian 2000, 2003a, 2006; Eckey 1954; Kokilavani et al. 2007; Lyon 1972; Panneerselvam et al. 2005; and many others). The oil offers low cholesterol and a high proportion of polyunsaturated fat, and is used in salad or as a cooking oil, shortening, and margarine. Sesame proteins are especially rich in the essential sulfur-containing amino acid methionine, and in tryptophan, and sesame meal flour is an excellent source of methionine-rich proteins (Villegas et al. 1968). These can be a valuable supplement to pulse proteins, such as those in beans and chickpeas, which contain adequate amounts of lysine but are usually deficient in sulfur-containing amino acids (Fernández de Campoy 1981). Lyon (1972) reported a protein content range of 17–32%. Godfrey et al. (1976) have suggested a combination of cowpea (deficient in methionine) and sesame to overcome the problem of limited amino acids. The carbohydrate content of sesame seeds (21– 25%) is comparable to that of peanuts and higher than that of soybean seeds (Joshi 1961). The chief constituent of sesame seed is its oil, which constitutes 40% to 68% of seed weight, determined by cultivar, thus superior to most other oil crops (Hussein and Noaman 1976; Salunkhe et al. 1991; Tinay et al. 1976). Sesame oil contains about 80% unsaturated fatty acids, with oleic (37–50%) and linoleic (37–47%) predominant and present in approximately equal amounts (Lyon 1972). Sesame has more unsaturated fatty acids than many other vegetable oils, and its higher proportion of unsaturated to saturated fatty acids makes it a potentially important dietary source of essential fatty acids. Linoleic acid is required for cell membranes, for transportation of cholesterol in the bloodstream, and for blood clotting, as carefully reviewed in Salunkhe et al. (1991). Sesame seeds are a good source of calcium, phosphorus, and iron. Half to two-thirds of the calcium in the seed is present as oxalate, and a major part of it is located in the testa. Generally, seeds are used after dehulling; therefore, the oxalate does not interfere with the absorption of calcium. Sesame seeds contain high levels of thiamine, riboflavin, and nicotinic acid (Tabekhia and Mohammed 1971). When made into sesame butter, they lose 52.5% of their thiamine and 50.2% of their nicotinic acid. Sesame’s characteristic flavor comes about by dry-roasting the dehulled material, as elucidated by Shahidi, Hughes, and Tan in Chapter 9 of this volume. The seeds are rich in the B vitamins thiamin, riboflavin, and niacin (United States Nutrition Program 1968), vitamin E, and small amounts of trace elements (Mo, Zn, Co, and I).

Edible Use Sesame seed, paste, and oil are valued in a very wide range of edible products, raw or roasted; the whole seeds are added to breads, pastries, crackers, and confectionary (Bedigian 2000, 2004a), and are sprinkled on breads, rolls, and cookies before baking. Crude sesame oil pressed from the seed is a salad oil, while “refined” oil from crushed toasted seeds is a flavoring after cooking. Note that there are two types of sesame oil. Oil pressed from untoasted seeds is light colored and fragranced, and the best choice for stir-frying and baking because of its high smoke point. Oil from toasted seeds, labeled “toasted sesame oil,” is dark and highly fragranced, and particularly prized in Asian recipes. Its best use is to flavor dishes after cooking; it is not suitable for baking or frying. The seed crushed into a nutty paste is labeled “salad dressing” or tahini, a nutritious spread, used in the Middle East for flavoring mashed chickpeas, garlic, and lemon juice to make the popular dip hummus bi tahini. Halvah is a confection made of crushed and sweetened sesame seeds, especially renowned in Eastern Anatolia, Lebanon, and Syria. Toasted seeds mixed with caramelized sugar make

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Sesame: The Genus Sesamum

brittle candies. Sesame oil in small quantities aids in the manufacture of margarine and compound cooking fats. Elleuch et al. (2006) describe the quality characteristics of sesame seeds and byproducts. Young leaves are a vegetable in sub-Saharan Africa and China. While cultivated primarily for its oily seed, sesame is exceptionally beneficial because of its dual use as leafy vegetable and seed crop. It is a readily available source of nourishment during famine or hardship. Latham (1965) found that the dark green leaves are rich sources of carotene, ascorbic acid, iron, and calcium; they contain useful quantities of protein and “it is highly desirable that rural peoples continue to eat them.” Cooked young shoots and leaves make soups and sauces in Africa, as do the leaves of other Sesamum species, and occasionally other genera (Bedigian 2004b). The leaves may be dried and stored for use during food scarcity. Several other species of Sesamum are cultivated, that is, deliberately planted intermittently, especially in Africa. Most common is S. radiatum Thonn ex Hornem, which like sesame is known as benniseed (Bedigian 2004b).

Industrial Use For centuries, sesame oil has been used in the manufacture of soaps and lubricants, and as lamp oil and an ingredient in cosmetics. Sesame oil is a pharmaceutical solvent, and as an insecticide it is exceptionally synergistic with pyrethrin, which is derived from Pyrethrum cinerarifolium Trev. (Bedigian et al. 1985; Haller et al. 1942). It is a carrier for medicines and perfumes. The oil is versatile as a substitute for olive oil, and in the manufacture of penicillin injection in oil and wax U.S.P. and ammonia liniment N.F. (Youngken 1950). Other unsaponifiable substances in sesame oil include sterols, triterpenes, pigments, and tocopherols. In India, sesame oil is a component of vegetable ghee and used for anointing hair and skin. Lowgrade oils are included in the manufacture of soaps, paints, and lubricants; alone, it was a lamp-oil in centuries past. Ash from burned stems is a medicinal salt (Bedigian and Harlan 1983).

Medicinal Use Duhoon and Tripathi (2003) offer a detailed summary of medicinal and curative properties of sesame. Sesame oil has pharmaceutical uses and is in the British pharmacopoeia for making liniments and ointments. Massaging sesame oil into the scalp once a week is an excellent way to nourish the scalp and restore the natural balance and luster of hair. Sesame oil, called til oil in Sanskrit, has been in use since Vedic times. Sesame oil is preferred traditionally for abhyanga, the daily Ayurvedic self-massage; the oil is allowed to soak in 5–15 minutes before taking a warm bath or shower, so the oil can be absorbed and nourish and detoxify the tissue layers. Warm water is important as it opens the pores, allowing the oil to permeate further into the body. To ease tension and relieve insomnia, oil is applied in the evening, before bed; this procedure should include oiling the soles of the feet. Herbs or essential oils help achieve a specific desired effect: for example, lavender oil for stress and tension, frankincense for arthritic pain, and ginger to increase circulation. Various sesame plant parts are included in native medicines in Africa and Asia for a variety of ailments (Bedigian 2003b). The mucilaginous leaves and leaf sap are used to treat fever, as a remedy for cough and sore eyes, and to kill head lice; the sap is taken to facilitate childbirth and to treat dysentery and gonorrhea, and is used in dressings after circumcision (Bedigian 2003b, 2004b). In eastern and southern Africa, the leaves play a role in the treatment of snakebites and malaria; in India and China, in the treatment of cancers. The oil is used to treat cough and earache, and as an emmenagogue and abortifacient. Sesame seeds are valued for their laxative effect. Sesame seed residue, which remains after oil extraction, is a protein-rich livestock and poultry feed. Sesame even produces beneficial waste: the testa (seed coat), discarded in the preparation of tahini and halvah, is endowed with therapeutic constituents (Grougnet, Magiatis, and Skaltsounis in Chapter 4 of this book).

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9

Fiber Use All parts of the sesame plant are used. Though little remarked upon, sesame is a valuable fiber plant. The woody stems are used for shady shelters, hut roofs, and animal pens. Uprooting, the harvest method in Syria along the Euphrates, parts of Eastern Anatolia, and Armenia, regions where trees are scarce (Bedigian 2004a, Rabo 1980), effectively exploits the woodiness of the plants as fuel for the earthen bread ovens of these regions. The ovens are specially designed to hold the husky sesame (and cotton) stalks in subsistence societies where recycling is the norm. For centuries, the Chinese have burned the oil to make soot for their fine ink blocks, and used as India ink.

Enfleurage—Use with Aromatic Extractions Enfleurage is an ancient method employed for the extraction of essential oils of flowers such as jasmine, rose, and tuberose. Theophrastus (ca. 300 BC: Sections 14–47) wrote in Concerning Odours: “Sesame-oil . . . receives rose-perfume better than other oils.” Excavations of Mesopotamia’s Mari palace have uncovered rooms where scented and unscented oils and tablets of accounting records of scented oils were stored (Brun 2000). Administrative archives from the eighteenth century BC show that a Lù raqqû (“perfume maker”) named Nûr-ili received filtered sesame oil and delivered scented oils in return. The scented oils were fragranced with myrtle, cypress, opopanax, odorous reed, and some oils that remain a mystery: supalum and tamrirum oils, and oil of Mari. The tablets document the use of several fragrant plants, including those yielding galbanum (Umbelliferae), storax (which produces a balsam used as a pungent-smelling fixative), and labdanum, which is derived from various species of rockrose. The texts indicate that some of the fragrant essences were extracted through maceration, without heating (particularly for cypress and myrtle), while others required heating (diqârâtim, cooking-pot oil). Enfleurage by heat was primarily for resin-based aromatic elements. A traditional procedure in the Unani pharmacy (Abdin and Abrol 2006), also practiced in India for centuries, is this: Place moist sesame seeds in alternate layers with flower petals for 12 to 18 hours. Discard spent blossoms and repeat with fresh petals several times. Crush the fragrant sesame seeds in a mill to obtain the scented oil. Enfleurage of roses (gul) with sesame seeds (Watt 1893) and expression of their oils is the method used for the preparation of Indian gulroghan hair-oil (Pal 1966).

Agronomic Attributes and Genetic Diversity: Ecosystem Services to Adverse Landscapes Sesame is a rain-fed crop in the semi-arid tropics. It is drought resistant and will succeed where there is as little as 400 mm of rain during the growing season (Cobley 1976). The crop is sensitive to excessive rainfall and waterlogged soils, and does best on deep, free-draining sandy soils. Traditionally, the crop is a field crop, often in monoculture, planted densely to prevent competition from weeds, but in villages in rural Africa and Yemen, it is grown most often by intercropping; hence sesame avoids the consequences of high fertilizer inputs and pesticides and their environmental consequences, as scrutinized by Clay (2004). Sesame tolerates intense heat well; Bedigian has seen sesame farmed in small patches among heavy boulders, concealed among heat-absorbing rock outcrops on the mountains above Maseno at the equator in Kenya, and near the deserts of Darfur, Sudan. Sesame grows on nearly pure Kordofan sands outside El Obeid, Sudan (Bedigian 1981, 1991). Sesame has many agriculturally favorable attributes. It grows under residual soil moisture without any supplemental irrigation, usually as a rain-fed crop. It sets seed and yields relatively well under high temperatures, is tolerant of drought, and does reasonably well on poor soils. In this way, it excels at adaptations to stressful physical environments. The reported life zone for sesame is from 11º to 29ºC, with an annual precipitation of 0.2 to 0.4 m and a soil pH of 4.3 to 8.7. The crop does best in warm temperatures with a long growing season. It is very sensitive to daylength and is

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Sesame: The Genus Sesamum

intolerant of waterlogging. It grows on marginal lands, where little else can survive. Sesame is useful in rotation and as a second crop. Sesame cultivars demonstrate a wide spectrum of maturing (4 weeks to 6 months) that enables farmers to hedge in harsh environments (Bedigian and Harlan 1983, Bedigian et al. 1986). Sesame encourages agricultural diversification after cereal staples. An economic benefit is its effectiveness as a trap crop versus the parasitic purple witchweed, Striga hermonthica (Delile) Benth. Bedigian and Harlan (1983) and Hess and Dodo (2004) have noted this protective effect. One season of crop rotation with sesame diminishes the population of Striga seeds in a field. Striga seed germination commences as usual, but because sesame is an unsuitable host plant, the sprouts soon die off. Admittedly, sesame strays from the strictest definition of a domesticated crop (Harlan 1992), inasmuch as most traditional cultivars display indeterminate growth habit, and capsules of most long-established cultivars shatter, releasing seed. On ripening, sesame capsules split, suddenly and forcefully, when the seeds are ripe, scattering them widely (hence the motto “Open sesame!”), so timeliness of harvest is important for maximizing yield. Sesame growers adapt to these factors by harvesting the racemes once they turn yellow, before the capsules open, and then binding these bundles of stalks to stand vertical to prevent excess harvest loss.

Harvest Considerable hand labor is needed during harvesting to prevent loss of the seeds. Perhaps because of its shattering characteristic, farmers sow sesame primarily on small plots, harvest by hand for local consumption, or on a larger scale in places where labor is cheap. Indeterminate growth habit, uneven ripening, and capsule shattering restrict wider sesame cultivation. Until recent years, this fact has been the major obstacle to sesame’s expansion as a commercial crop. The discovery of an indehiscent mutant by Derald G. Langham in 1943 permitted efforts toward development of a highyielding, shatter-resistant cultivar. Although researchers have made significant progress in sesame breeding, harvest losses resulting from shattering continue to limit much global production. Sesame plants are harvested 75–150 days after sowing, more commonly after 100–110 days. At maturity, leaves and stems turn yellow. Plants must be harvested before all capsules are mature to prevent field losses from shattering. Generally, farmers cut the racemes when they are still green, and then tie them in small bundles and place them upright in shocks in the field, as shown in Figure 1.2. Nuba farmers arranged the racemes artfully on unique circular or rectangular drying tables (Bedigian and Harlan 1983); branches are piled upon drying racks (rakouba) composed of wooden legs supporting a raised platform. The height of the platform differs, ranging from 0.25 m in some settlements to as high as 1.5 m elsewhere. Rakouba stacking designs vary also among communities. Some groups place the alternate layers horizontally at right angles forming a rectangle, some make a circular stack, and others form a triangular mound. Southern Sudan’s Nilotic populations dry sesame stalks tied or stapled onto distinctive, elaborate drying scaffolds, each design unique to a specific locality or ethnic group; bundles are arranged to maximize air flow, as shown in Figures 1.3–1.5, photographed in the remote, highly inaccessible region. This technique of scaffold drying is also practiced by the ethnically related Luo peoples of Kenya’s Siaya district, e.g., at Bondo village (Bedigian observations 1994). Some farmers prefer to uproot the entire plant. This is often done where wood is in short supply since the stalks and roots are subsequently used as kindling, as in the Armenian Highlands and Syria (Bedigian 2004a; also see photograph of this practice in Somalia, in Chapter 20 of this volume).

Breeding Breeding objectives for sesame include higher yields, improved plant architecture, resistance to diseases and pests, and indehiscent capsules. The degree of dehiscence is a cultivar characteristic and of great importance for mechanized harvesting. The discovery in 1943 of an indehiscent mutant

Introduction

11

Figure 1.2  Sesame racemes in the Nuba Mountains, Sudan, 1979, bundled by immigrant farmers from Western Sudan; this practice was atypical for the region. (Photo by the author.)

Figure 1.3  Sesame drying rack, Nimule, Southern Sudan, designed to allow air passage. (Photo courtesy Robbert van der Steeg, Catholic Relief Services, 2003.)

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Sesame: The Genus Sesamum

Figure 1.4  Sesame drying rack, “elephant” style, with Oketayot Cirino, Nimule, Southern Sudan. (Photo courtesy Robbert van der Steeg, Catholic Relief Services, 2003.)

Figure 1.5  Sesame drying rack, Ikotos, Southern Sudan. (Photo courtesy Robbert van der Steeg, Catholic Relief Services, 2003.)

Introduction

13

led to non-shattering cultivars that were, however, difficult to thresh. The introduction of papershell capsules into indehiscent plants helped solve this problem. Sesaco Corporation (San Antonio, Texas) developed cultivars with partially dehiscent fruits that open slightly but generally retain their seed (Langham and Wiemers 2002). Plant height to the first capsule is another cultivar trait important in mechanical harvesting.

Etymology Sesame is an example of a Wanderwort (Bedigian 2004a), a word that was spread throughout numerous languages and cultures, usually in connection with trade, so that it has become very difficult to establish its original etymology, or even its original language. The separation of Wanderwörter from loanwords is not possible unambiguously, and they are considered a special class of loanwords. That said, the name sesame and most of its derivatives in present-day European languages goes back to Greek sesamon [Σήσαμον] (Mycenaean Greek sasama), which itself is a non-Indo-European loan word. Those may have arisen from Akkadian šamaššammū, a compound of šamnu, “fat, oil” and šammum, “plant” (Bedigian 1984, 1985; Bedigian and Harlan 1986). This closely parallels the Sumerian name for sesame, še-giš-i, which is composed of two marks, giš, “plant” and i, “oil.” The first element of šamaššammū derives from the Semitic root ŠMN “fat,” which is common among Semitic tongues, e.g., Arabic as-samn [‫“ ]نمسلا‬fat, clarified butter,” Hebrew shemen [‫“ ]ןמש‬oil,” and Ugaritic shamn “oil.” Other Semitic forms for sesame are rather close, e.g., Aramaic šumšəm [‫]ܡܫܡܘܫ‬, Hebrew sumsum [‫]םושמוש‬, and modern Arabic as-simsim [‫]مسمسلا‬. It diffused from Aramaic (Muss-Arnolt 1892: 111) into Armenian as shushmah [Շ ո ւ ջ մ ա յ] and susam [ս ո ւ ս ա մ] (Koushakdjian and Khantrouni 1976; Kouyoumdjian 1961); the latter was adopted into Albanian, Serbian, and Turkish (Bedigian 2000, 2004a). Cognates of Persian konjed are widely attested in Iranian languages beginning in Middle Iranian times, e.g., Middle Persian kunjid, Khotanese kumjsata-, but its ultimate origin does not seem to be known (Sims-Williams, pers. comm. 2009). Bedigian (2004a) offers a suggestion of its derivation from classical Armenian. Armenian and Azerbaijani küncüt [կենճիթ], Georgian kunjuti [ქუნჯუთი], Kazakh künjit [күнжіт], Pashto kunjite [‫]ېتجنوك‬, and Turkmen künji evolved via Modern Farsi konjed [‫ ]دجنک‬from Middle Persian kunjid; it is in Russian as kunzhut [кунжут], Estonian as kunžuut, and Yiddish as kunzhut [‫]טושזנוק‬. In India, sesame’s center of origin, there are two independent names for sesame: Sanskrit tila [ति ल] appears in the Rigveda and is the source of all names in North India, and some southern Indian names also, e.g., Hindi, Urdu, Punjabi, and Bengali til [ति ल, ‫لت‬, ਤਿ ਲ, তিল], Gujarati tal [તલ], Sinhala tala, and Dhivehi thileyo [‫] ޮޔ ެލ ިތ‬, but also Telugu tillu [తిలలు] (Mayrhofer 1953). The origin of that word family is not known, but sources we consulted suspect it to derive from a pre-Aryan North Indian language predating Sanskrit, perhaps related to the contemporary Munda languages (Bedigian 1984; Bedigian and Harlan 1896). There is a similar Akkadian term, tallum, meaning “oil.” Conversely, most of the Dravidian languages in South India feature an independent name for sesame, exemplified by Tamil and Kannada ellu [எள ்ள ு, ಎಳ್ಳು]. The latter name resembles Greek elaion [έλαίον] now used for olive, and Akkadian ellu, “fruit,” suggesting a possible common origin for the names of these locally important oil crops; there is also Sumerian ili, “sesame.” Although this group of names seems to be exclusively associated with Southern Dravidian, a remote connection to the til-words cannot be ruled out completely. From both Indian roots, words with the generalized meaning “oil, liquid fat” are derived: e.g., Sanskrit taila [त ल ै ], Gujarati tel [ત લ ે ], and Dhivehi theyo [‫ ] ޮޔ ެތ‬vs. Tamil enney [என ்னெய ]் , the latter being formed from ellu [எள ்ள ு] “sesame” and ney [நெய ]் “fat”; also Malayalam enna [എണ ണ ് ] and Kannada enne [ಎಣ್ಣೆ] “oil,” probably a parallel construction. This may represent a semantic shift from the name sesame, the ancient major oil crop, to the general word oil (Bedigian 1984, 2004a; Bedigian and Harlan 1986).

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Sesame: The Genus Sesamum

English gingelly (used mainly in India) and Portuguese gergelim (common in Brazil) have their source in the early colonial period; their origin is Arabic al-juljulan [‫“ ]نالجلجلا‬sesame” (Bedigian 1984, 2004a; Bedigian and Harlan 1986), which derives from the Arabic noun jaljala [‫]ةلجلج‬ “sound, echo,” referring to the rattling sound of ripe seeds within the capsule; this Arabic term has an obvious onomatopoetic character. There are a few cognate names: e.g., Maltese ġulġlien, Hindi gingli [गि ग ं ल ी], and Spanish ajonjolí. Other, now less common names of sesame in English are tilseed (from Hindi/Urdu til [ति ल, ‫ )]لت‬and benniseed or benne (from Mande, Wolof bene). Bedigian, in Chapter 24 of this volume, expands the discussion of these and other select African names. A Chinese compound term for sesame is hu ma [胡麻] “wild/foreign hemp”; the element ma means “hemp,” emphasizing sesame’s use as fiber plant, and hu emphasizes its foreign introduction (Bedigian 1984; Bedigian and Harlan 1986). Names used in English include sesame, benne, benniseed; in French, sésame; in Portuguese, gergelim, gimgelim, sésamo; in Swahili, simsim, ufuta, wangila. Bedigian and the African linguistic historian Christopher Ehret are preparing a comprehensive analysis of African names.

Sesame for Luck and Protection against the Evil Eye “History and Lore of Sesame in Southwest Asia” (Bedigian 2004a) documents sesame’s significance in ritual practices across cultures. Instances of sesame used to ward off evil spirits exist in such disparate groups as Syrian Christians (Bedigian 2004a) and the Nuba of Sudan (Bedigian and Harlan 1983), and in Georgia’s and South Carolina’s Lowcountry, and the Caribbean (Bedigian, Chapter 24, this volume). Add to that corpus of literature an example by Dolader (1999) of Jewish nuptials: “Among the lower classes, it was customary for the bridegroom’s family to send small loaves of sesame bread to their relatives and to the bride’s family prior to the wedding. The purpose of this gift, known as the gorban (sacrifice), was to free the groom from the evil eye.”

Sesame Motif in Art, Literature, Music, and Film Sesame has been an inspiration in world literature, art, music, and related intellectual activities (Bedigian 1984, 2000, 2004a; Bedigian and Harlan 1986). Sesame is one of many other seeds, leaves, and flowers that form an essential component of religious ceremonies (Bedigian 2004a; Bedigian and Harlan 1986; Mehra 1967, 2000). Thus far, Persian sources have been only briefly mentioned (Bedigian 2000). The earliest appearance of the word konjed seems to be in the poetry of Nezami Ganjavi (ca. 1141 to 1209), who lived in the Caucasus. Rumi (d. 1274) and Amir Khosrow of Delhi (d. thirteenth century) have used the word as well. Figure 1.6 illustrates two Persian verses that include metaphoric references to sesame. Nezami conveys: No matter what ploys the adversary tries, he will be defeated. Rumi used sesame allegorically to relate that while the ascetic is fasting, deprived of nourishment, those about him are heedlessly consuming, with the consequence that nothing remains to shed light. Boyce (2005: 29) describes the contribution of sesame to a Persian New Year (Nō Rūz) feast: “in front of all was a platter bearing a sweet dish made only for this festival, which had in it dates, pounded sesame seeds, rose water and sugar-candy water.” Visionary social theorist John Ruskin’s use of sesame allegorically in his lectures Sesame and Lilies (1865) has puzzled numerous critics, as editor Rounds noted (1916). Commenting on the lack of correspondence between Ruskin’s titles and the contents of those essays, Harrison (1925) griped: “The volume so oddly named Sesame and Lilies. Why Sesame and Lilies I have never been able to unriddle.” Bedigian also, perplexed but determined to hunt for the connection, observes that the sesame motif is a double entendre. Reverend Ruskin was among a literate few who constructed learned teachings. Employing the magical incantation Open Sesame! Ruskin opens with words by Lucian, the Syrian Satirist from classical antiquity, born in Samosata on the Euphrates in Eastern Anatolia (AD 120–190): “You shall each have a cake of sesame—and ten pound,” quoting The Fisherman.

15

Introduction

  Should the king mobilize an army like a pile of sesame, My troops are all sesame-eating birds Nezami (12th century)

The Christ-like soul is starving like a crow His donkey devours sesame by the load Once the donkey eats all the sesame What is there left for us to draw our lamp-oil? Rumi (13th century) Figure 1.6  Persian verses, provided and translated by Hossein Kamaly, Barnard College, New York.

Using Open Sesame! as metaphor (Bedigian 2004a), Ruskin evokes its royal role as King to open the Treasure House of Knowledge, in stark contrast to Lilies, Queens of Gardens: “dealing in a better bread;—bread made of that old enchanted Arabian grain, the Sesame, which opens doors;— doors not of robbers,” but of Kings’ Treasuries. “When men are rightly occupied their amusement grows out of their work, as the colour-petals out of a fruitful flower; when they are faithfully helpful and compassionate, all their emotions become steady, deep … to ‘advance in life’—in life itself, not the trappings of it. ... He only is advancing in life whose heart is getting softer, whose blood warmer, whose brain quicker, whose spirit is entering into Living peace.” This immediately precedes Ruskin’s antiwar message: “For an unjust war, men’s bodies and souls have both to be bought; and the best tools of war for them besides, which make such war costly to the maximum.” Open Sesame! The magical incantation is drawn on for numerous diverse causes, its literary origins delineated above and previously (Bedigian 2000, 2004a). An unsung instance of its use is in the title of famed jazz trumpeter Freddie Hubbard’s first album as headliner recorded in 1960, and for its title track. Hubbard, one of the most influential trumpet players of the last third of the 20th century, led some talented all-stars in swinging, absorbing hard bop jazz, full of improvisation. Here Hubbard was still in his early years, as was expert pianist McCoy Tyner. Critics agree, Open Sesame is, without a doubt, Hubbard’s best work for Blue Note Records.

Sesame Oil Presses A Chinese film released in 1993 called Women from the Lake of Scented Souls is fictional, but it involves a woman who runs a successful sesame oil mill in present-day China. Edible oils historian Carter Litchfield, (of Oléarius Editions, specializing in books on historic oil mills) (pers. comm. 2006) has seen the movie and noted that about 5–8% of the filming was inside an operating sesame oil mill. That movie shows off the operating machinery in that mill quite well, and according to a reviewer (Hunter 1994), “You learn a lot about sesame oil.” The video version of Women was released in 1995; in 2004 the movie was renamed Woman Sesame Oil Maker and released in DVD format, in Mandarin with English subtitles. An appealing, slow-paced Chinese film, Woman Sesame Oil Maker is set in a rural area of China, and features a woman who makes the best sesame

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Sesame: The Genus Sesamum

oil in the neighborhood. A Japanese businesswoman wants to buy her oil and proposes to modernize the oil mill. The woman agrees to cooperate. Her son is in love with a local girl, but the girl’s parents don’t let her marry him because the boy has epilepsy. However, using the poor financial state of the girl’s family, the woman arranges this uneasy marriage. Many story lines remain unresolved, but viewers might be interested in the fact that it received the Grand Prize at the 1993 Berlin Film Festival. Set in rural China, the original short story from which the film was adapted, “The Sesame Oil Mill” by Zhou Daxin (1994), has all the intrigue of a soap opera. There are wonderful details about oil yield (as high as 57%), oil extraction techniques, and the economics of the business, and vivid descriptions of the aroma of the roasting seeds, as referenced earlier by Bedigian (2000). The striking series of woodblock engravings shown here (Figures 1.7–1.15) illustrating Japanese sesame oil pressing in early times was done by Matsukawa Hanzan, active circa 1850 to 1882. Available in a limited edition, Seiyū Roku [On Oil Manufacturing], written by Nagatsune Ōkura, is an English translation by Eiko Ariga of the original 1836 Japanese edition and edited by Litchfield (Okura 1974), who generously provided us the illustrations. Another view of the sesame wedge press (Figure 1.16) is seen in Knight’s review of the Japanese Exhibit, “Crude and Curious Inventions at the Centennial Exhibition.” Knight (1877) wrote: “The vegetable oil sesamum (which substantially retains with us its Arabic and Greek names: Ar. simsim; Gr. sesamon) yields a large proportion of the oil of the Orient. Fig. 168 is a wedge press in which the ground and heated seeds of the Sesamum indica are pressed, the meal being placed inside of a slack tub and beneath a follower on which rests the beam, which is depressed by wedges driven in with poles, suspended from the roof and operated by a man at each side.” Knight (1877) further expounds: “The oil mill of Zanzibar for cocoa-nut and Sesamum oil is like that of India and Ceylon. It has a wooden mortar in which is a conical cavity four ft deep and 3 ft in diameter at top, with a broad, flat rim. A rolling-pestle 6 in. in diameter is secured in the bottom of the mortar; its upper end to a beam to the extremity of which a camel is harnessed. The correspondence between the apparatus of India and Zanzibar is not extraordinary when we reflect that the ocean has so long been a common passage way to the adventurous Arab sailors.” Traditional constructions that housed similar sesame oil presses (asara, pl. asarat) in African and Arabian towns varied according to local materials available. Some ancient beam presses are still extant, which Bedigian visited and photographed in Sudan in 1979 and in Yemen in 1998. In Sudan, al fresco camel-powered presses enclosed by thorn and grass fences were still operational in 1980 in El Obeid (Figure 1.17) and Gedaref, as well as in the Yemeni towns Seiyun and Tarim, in Wadi Hadhramaut, in 1998 (Bedigian 2004a). In contrast, the living museum of Sana’a, where stone is the ubiquitous building material, has camel-driven presses housed inside sturdy stone structures. Hardwearing mortars and pestles constructed of solid Acacia nilotica wood are the norm. French explorer Captain Charles Guillain explored the east coast of Africa between 1846 and 1849, observing its history, geography, and commerce. He described carefully the crops cultivated, including sesame, and remarked on customs unfamiliar to him in a two-volume tome, with an oversized, supplemental volume of large-format lithographs. Figure 1.18, an 1847 lithograph titled “Moulin à huile en mouvement et travaux divers exécutés à Moguedchou,” by A. Bayot, illustrates details within a Somali workshop that not only produced sesame seed oil but also spun cotton. Guillain (1856) logged: “All of southern Somalia, through the coastal city of Banaadir, was connected to the vast network of Muslim trade, which ran from the Arabian Peninsula, and the region of the Persian Gulf as far as western India. The coastal exporters almost always found a foreign market for local produce such as cattle, skins, butter, ivory, cereals, cotton, sesame, orchill and local cloth. Imports included rice, sugar, silk and cotton cloth, yarn for local industry, metal utensils etc. These sailing boats had been a common method of navigation since antiquity in Hadhramaut, the Yemen. Even though the heart of the whole system was foreign trade, the Arabs began to give life to industries that transformed local life. The Yemeni introduced the technique of extracting oil from

Introduction

17

Figure 1.7  Kantō oil extraction work area. Litchfield indicates that processing for sesame and rapeseed were similar. According to Tomoko Steen, Library of Congress, the image represents the Oil Collection method from Edo Period (1603-1868). This image and those following, courtesy Carter Litchfield, Editor, Oléarius Editions, New Brunswick, NJ. His re-publication appeared as (From Okura, N. 1974. An English translation of the original 1836 Japanese edition, Seiyū Roku. On Oil Manufacturing, C. Litchfield, ed. and A. Eiko, tr., Oléarius Editions, New Brunswick, NJ.)

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Sesame: The Genus Sesamum

Figure 1.8  Pressing oil from seed powder produced by watermill. (From Okura, N. 1974. An English translation of the original 1836 Japanese edition, Seiyū Roku. On Oil Manufacturing, C. Litchfield, ed. and A. Eiko, tr., Oléarius Editions, New Brunswick, NJ.)

Figure 1.9  Steaming process for the watermill method. (From Okura, N. 1974. An English translation of the original 1836 Japanese edition, Seiyū Roku. On Oil Manufacturing, C. Litchfield, ed. and A. Eiko, tr., Oléarius Editions, New Brunswick, NJ.)

Introduction

19

Figure 1.10  Nada method oil pressing. (From Okura, N. 1974. An English translation of the original 1836 Japanese edition, Seiyū Roku. On Oil Manufacturing. C. Litchfield, ed. and A. Eiko, tr., Oléarius Editions, New Brunswick, NJ.)

Figure 1.11  Full view beam press. (From Okura, N. 1974. An English translation of the original 1836 Japanese edition, Seiyū Roku. On Oil Manufacturing, C. Litchfield, ed. and A. Eiko, tr., Oléarius Editions, New Brunswick, NJ.)

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Sesame: The Genus Sesamum

(A)

(B) Figure 1.12  (A) Four steps in Ōsaka method oil extraction. Lower right, parching seeds in roasting pan. Center, treading the parched seeds with a tilt hammer. (B) Lower left, sifting the powdered seeds. Upper left, arranging the lumps of pressed oil cake. (From Okura, N. 1974. An English translation of the original 1836 Japanese edition, Seiyū Roku. On Oil Manufacturing, C. Litchfield, ed. and A. Eiko, tr., Oléarius Editions, New Brunswick, NJ.)

Introduction

21

Figure 1.13  Hammering the oil press with mauls in the Ōsaka method of oil extraction. (From Okura, N. 1974. An English translation of the original 1836 Japanese edition Seiyū Roku. On Oil Manufacturing, C. Litchfield, ed. and A. Eiko, tr., Oléarius Editions, New Brunswick, NJ.)

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Sesame: The Genus Sesamum

Figure 1.14  The powdered cake from the first round of pressing is divided up and taken to the steamer. (From Okura, N. 1974. An English translation of the original 1836 Japanese edition, Seiyū Roku. On Oil Manufacturing, C. Litchfield, ed. and A. Eiko, tr., Oléarius Editions, New Brunswick, NJ.)

sesame and until several decades ago the production of presses was still exclusive to them. They even tried to produce glass.”

Sesame and Cultural Survival A study of sesame is a peek at past life ways. Subsistence farmers have grown sesame in Asia and Africa for several millennia, often intercropped with other essential cereal and legume species. Smallholders have safeguarded and created new biological diversity, availing themselves of environmental influences for selection, managing soil and water needs, and maintaining their livelihoods with the help of sesame, even under harsh conditions. Sesame is a crop that can succeed in locations where few others can, and without extraordinary inputs of fertilizer, pesticide, fossil fuels, or arduous labor. Climate change concerns have finally brought attention to the world’s harshest dry, marginal lands. Particularly vulnerable, those hardest hit have little or no stake in the prosperity that produced these imminent and ongoing threats to their environment. Drought and high temperatures as well as increasing population pressures combine to impact the indigenous farmers’ livelihood, as Yardley (2009) shows about farmers in Andhra Pradesh. Comments to the article are also enlightening. Blogger Aravinda wrote: “of the simple millet—a sturdy crop which requires no pesticide, fertilizer or irrigation, which is more nutritious than wheat or rice, high in bio-available protein, iron and calcium, making it an ideal food from infancy till old age. This traditional food has become ‘old-fashioned’ and unprofitable.” The same can be said of sesame. Geographic isolation and poverty have permitted well-adapted sesame cultivars to evolve in remote places, retaining their unique genetic characteristics because there was little exchange of subsistence crops with the outside, and because traditional practice generally involves saving seeds from one year to plant the next (Bedigian 1991). As sesame is predominantly a self-pollinated crop, the distinctive characteristic of each cultivar remains well preserved. But since traditional farmers’ livelihoods are endangered (Bedigian 2003a, 2004b), those ancient cultivars may disappear.

23

Introduction

(A)

(B) Figure 1.15  (A) Four steps in the preparation of white sesame oil. Lower left, filtering the refined oil through bags made of filter paper. Left center, scooping up the filtered oil. (B) Upper left, cooking the refined oil to remove water. Upper right, checking the color of the refined oil in a white cup. (From Okura, N. 1974. An English translation of the original 1836 Japanese edition, Seiyū Roku. On Oil Manufacturing, C. Litchfield, ed. and A. Eiko, tr., Oléarius Editions, New Brunswick, NJ.)

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Sesame: The Genus Sesamum

Figure 1.16  Beam press for crushing sesame, illustrated in Knight (1877). Crude and curious inventions at the Centennial Exhibition, Japanese exhibit.

Figure 1.17  Camel-powered oil press (asara), El Obeid, Sudan. (Photo by D. Bedigian, 1980.)

Figure 1.18  Camel-powered oil mill in operation, Mogadechio, Somalia. (From Moulin a huile en mouvement et travaux divers executes a Moguedchou. Arthus Bertrand, editeur. A. Bayot, lithographer. Imp. Becquet fr.r. des Noyers, 37, Paris. ‘Voyage a la cote orientale díAfrique.’ printed upper left. Published in Guillain 1856.)

Introduction

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Paradox of Sesame: “Queen of Oilseeds” Yet Orphan Crop Herein lies a conundrum: sesame seeds are so popular that the plant is often dubbed the “Queen of Oilseeds.” There are many reasons why writers label sesame thus: its nutritional constituents— methionine-rich proteins, antioxidant-enhanced oil protected from rancidity—and a delicious nutty aroma and flavor. On the other hand, sesame is largely a crop of “the underclass: The world’s exploited, forgotten, ignored, neglected, and rejected” (Bedigian 1984). Geneticist Jack Harlan often referred to sesame as a “poor man’s crop.” Perhaps for that reason, it remains neglected. It lacks research support compared with other major crops. No international crop research center (e.g., ICARDA, ICRISAT) concentrates on sesame, leading Mahmoud et al. (1995) to designate sesame an “orphan crop” and urge collection of Sesamum species because it is “in imminent danger of genetic erosion.” Bedigian has completed that mission. Over a decade ago, the International Plant Genetic Resources Institute, FAO, prepared a list of crops (Padulosi 1998) for its publication series Promoting the Conservation and Use of Underutilized and Neglected Crops, but it cut sesame from that original list. The Global Crop Diversity Trust’s mandate, “to prepare conservation strategies to protect against an environmental and development crisis: the loss of the crop resources that provide the first line of defense for farmers seeking food security under marginal and continually evolving circumstances,” is “obliged to prioritize Annex I crops. Given financial limitations, they have not been able to go beyond Annex I in practical work, because we have not yet dealt with all the Annex I crops” (Cary Fowler pers. comm. July 2009). In the horse-trading that ensued, the Trust too dropped sesame from their list of priority crops. No university in the United States has any scientist doing research on sesame. Among the paltry handful of sesame workers, some have undermined progress by being more competitive than collaborative. Research on sesame lacks funding support worldwide. Even today, sesame cultivation is primarily among the poor and disenfranchised; still, sesame is a major commodity in most territories where it is grown. The danger is that with habitat loss and genetic erosion, out-migration from rural areas to urban, adoption of “new crops,” and meteoric modernization, subsistence cultivators and their agricultural practices are rapidly disappearing. Although ignored as a research subject, Sesamum is an indispensable food to its growers (Bedigian 1991, 2000, 2004a, 2004b, 2006; Bedigian and Harlan 1983). Drought-tolerant (see Bedigian, Chapter 2 of this volume) and highly palatable, it shows excellent potential under low rainfall and high temperatures. Battisti and Naylor (2009) published dire warnings of future food insecurity with unprecedented seasonal heat worldwide. Under these threats, expansion of sesame, the “Queen” oilseed crop, seems ideal. Beneath the heading Neglected Crops, Wortman and Cummings (1978) wrote: “Many important crops receive little attention from scientists. Vegetable crops are mankind’s richest source of vitamins and minerals. They are a readily available solution to problems of malnutrition which cannot be entirely met by increasing the availability of calories from cereals or root crops … Other major neglected crops are … several species of oilseed field crops including sesame, sunflower, safflower and castor bean.” We estimate that three quarters of the genetic diversity of our world’s agricultural crops has been lost in the past century (Bedigian 2003c; Brookfield et al. 2002). Domesticated, improved, and conserved by poor farmers over millennia, valuable ex situ collections have, of late, been abandoned or discarded. Gary Nabhan (2002) warned about heirloom varieties as orphan crops: “Many will disappear very soon … Such seeds will die with the old people, that is because the distinctive seeds are entwined with certain families or communities who save seeds at will—by heart, you might say— without thinking of the scientific or cultural value of the seeds … As small landholders die or as economic changes force them off their parcels, this diversity is left behind in sheds and cellars that are ultimately cleaned out, torn down, or refurbished. The seeds and their stories lose their viability, and their passing goes virtually unnoticed … That is why … [we] call them ‘orphan crops.’ That

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Sesame: The Genus Sesamum

term would have appealed to Saint Francis, for his inclination always led him to work with what was neglected.” In reality, sesame itself is the prize that for millennia has provisioned those who dwell on marginal lands, in harsh drought and intense heat. Enclosed in a paradox of the magical invocation with high symbolic value: Open, Sesame! Sesame itself is the stored treasure, waiting to open!

Acknowledgments Countless nameless subsistence sesame growers have contributed to this research. They receive my highest admiration, for laboring quietly without accolades, for simple survival. I am indebted to librarians with various backgrounds who have supported these diverse research interests, at the Leonard Lief Library, Lehman College, City University of New York; Olive Kettering Library, Antioch College, Yellow Springs, Ohio; Greene County Public Library, Xenia, Ohio; Missouri Botanical Garden, St. Louis; University of Illinois, Urbana-Champaign; they have assisted in unearthing frequently poorly cited literature with few holding libraries, which helped me immeasurably to complete this book. Carter Litchfield (Oléarius Editions) and Michelle B. Cadoree Bradley (reference specialist, Science, Technology and Business Division, Library of Congress) generously contributed illustrations of Japanese oil presses. Hossein Kamaly, assistant professor of Middle Eastern and Islamic Studies, Department of Asian and Middle Eastern Cultures, Barnard College, New York, supplied and translated several verses about konjed, sesame, from Persian. Robbert van der Steeg, then associate expert at IPGRI (now Bioversity International) provided photographs of styles of stacking harvested sesame stalks from southern Sudan, in 2003. I am enduringly grateful to Edward Kennelly, head of the Department of Biology, Lehman College, CUNY, for indispensable affiliation with his phytochemistry laboratory, which enabled valuable exchanges with Ed, his post-docs, and graduate students.

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Sesame and 2 Cultivated Wild Relatives in the Genus Sesamum L. Dorothea Bedigian Contents Introduction.......................................................................................................................................34 Description of Cultivated Sesame.....................................................................................................34 Sesame Nomenclature and Lineage.................................................................................................. 38 Methodology..................................................................................................................................... 39 Botanical Description........................................................................................................................ 39 Stem............................................................................................................................................. 39 Leaves........................................................................................................................................... 39 Flowers.........................................................................................................................................40 Fruit..............................................................................................................................................40 Seeds............................................................................................................................................40 Functional Form: Glandular Trichomes....................................................................................... 41 Growth and Development................................................................................................................. 43 Synergistic Sesame Lignans............................................................................................................. 43 Ecology of Sesame and Various Wild Relatives............................................................................... 45 Phenotypic Variation of Cultivated Sesame...................................................................................... 47 Sesame Seed Color Relative to Oil Content..................................................................................... 48 Sesame Domestication...................................................................................................................... 49 Biogeography and Crop Movements................................................................................................ 51 Sesamum Systematics Misconstrued................................................................................................. 51 Sections of Sesamum L..................................................................................................................... 53 Section Sesamum.......................................................................................................................... 53 Section Chamaesesamum Benth.................................................................................................. 53 Section Sesamopteris Endl........................................................................................................... 53 Sesamum alatum Thonn.......................................................................................................... 54 Section Aptera Seidensticker....................................................................................................... 57 Sesamum angolense Welw....................................................................................................... 57 Sesamum angustifolium (Oliv.) Engl....................................................................................... 59 Section under Scrutiny................................................................................................................. 61 S. radiatum Schumacher and Thonner.................................................................................... 61 Sesamum latifolium Gillett...................................................................................................... 65 Genetic Relationships Determined by Interspecific Hybridizations................................................. 67 Sesame Genetic Resources in Gene Banks....................................................................................... 67 Germplasm Resources and Policies: The Example of Ethiopia........................................................ 68 Conclusions....................................................................................................................................... 68 Acknowledgments............................................................................................................................. 68 References......................................................................................................................................... 69 33

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Introduction Knowledge of the genetic range of and relationships between cultivars is useful in breeding programs, since a wide range of identified genetic diversity in parents is valuable in hybridization efforts. The goal of most sesame breeders is to achieve high-yielding, non-shattering, disease-resistant cultivars.

Description of Cultivated Sesame Sesame (Sesamum indicum L.), illustrated here in an early drawing from Köhler’s (1877) MedizinalPflanzen (Figure  2.1), is an erect, tropical herbaceous annual in the Pedaliaceae family that grows to a height of 0.5–2 m, depending on cultivar and growth conditions. Sesame genotypes display extraordinary genetic diversity (Abdellatef et al. 2008; Bedigian 1981, 1984, 1988, 1991, 2000, 2003a; Bedigian and Harlan 1983; Bedigian et al. 1986; Brar and Ahuja 1979; Laurentin and Karlovsky 2006; Xiurong et al. 2000). Morphologically, some cultivars are highly branched (Figure 2.2), whereas others have a single stem, or 2 to 3 at most (Figure 2.3). Leaves are variable, on average 7.5–12.5 cm long if entire, with upper bracts narrowly oblong, and the middle and lower leaves ovate or lanceolate and toothed; the lower ones are lobed or palmate, occasionally trifoliolate (Figure 2.4). The leaves are hairy on both sides. Many consider the plants to have an “unpleasant odor” (Bedigian 2004d). The fruit is an oblong quadrangular capsule, slightly compressed, deeply four-grooved, 1.5–5 cm long (Figure 2.5), containing 50–100 or more oval-, pear-, or teardrop-shaped seeds, most 2–3 mm long and approximately 1.5 mm wide. Seed colors are black, brown, tan, beige, rust red, mustard yellow, ivory, or white. The seeds are mature 4–6 weeks after fertilization. Plant maturity varies widely, from 70 to 180 days (Bedigian 1988; Bedigian and Harlan 1983). At maturity, leaves and

Figure 2.1  Köhler’s (1877) Medizinal-Pflanzen. (Köhler image courtesy Missouri Botanical Garden http:// www.botanicus.org.)

Cultivated Sesame and Wild Relatives in the Genus Sesamum L.

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Figure 2.2  Multibranched cultivar from Afghanistan, grown at South Farm, University of Illinois, Urbana, 1981. (Photo by the author.)

Figure 2.3  Monostem cultivar from Korea, grown at South Farm, University of Illinois, Urbana, 1981. (Photo by the author.)

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Sesame: The Genus Sesamum

5

7

8

13 12

6 9

10 11

1

2

15 16

a

3 4

17

19

14

18

Figure 2.4  Sesamum indicum. (Reproduced with permission from Seegeler, C.J.P. 1983. Agricultural Research Reports, 921. Centre for Agricultural Pub. and Documentation, Wageningen, the Netherlands. [Drawn by artist Juliet M. Beentje-Williamson.])

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Figure 2.5  Sesamum indicum bicarpellate capsules, South Farm, University of Illinois, Urbana, 1981. (Photo by the author.)

stems change from green to yellow, marking senescence and cessation of photosynthesis. They begin to dry and drop. Initiation of flowering is sensitive to photoperiod (Kotecha et al. 1975) and varies between cultivars. The campanulate (bell-shaped) flowers (Figure 2.6) begin to develop 3–8 weeks after sowing, and continue for many weeks, in some cases even until frost. The flowers open acropetally in sequence, from the base of a stem toward the apex (Figure 2.7). The corolla is fused and lobed, white, rose-pink, lavender, or mauve, in many cultivars with dark purple interior markings, resembling foxglove, borne in racemes in the leaf axils. The lowest lobe is often as much as 1 cm longer than

Figure 2.6  Sesamum indicum close-up of corolla showing glandular hairs, photographed at South Farm, University of Illinois, Urbana, 1982. (Photo by the author.)

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Figure 2.7  Sesamum indicum stem with flowers open and capsules maturing acropetally, from the base toward the apex. South Farm, University of Illinois, Urbana, 1981. (Photo by the author.)

the others, and often shaded purple. A yellow streak in the interior contains flavonoids (Bedigian 1984). Sesame is cleistogamous by nature, self-pollinating before the flowers open, although crosspollination by insects may occur. The growth habit of sesame landraces is indeterminate: that is, a plant continues to produce leaves, flowers, and capsules often as long as weather permits. Along these lines, sesame defies one of the standard dogmas of domestication, the shift from an indeterminate to a determinate growth pattern (Harlan 1992).

Sesame Nomenclature and Lineage Carl Linnaeus presented Sesamum indicum in his Species Plantarum (1753), to which he added a second species, Sesamum orientale L. As regards S. orientale, he referred to a considerable number of previous publications, but he based S. indicum on a Van Royen specimen only, and included Plukenet’s plant with trifid basal leaves (Wijnands 1983). Wijnands wrote that C. Commelin (1724) listed Sesamum orientale L. with trifid leaves, but also citing Seegeler (1983) offered that day length influences basal leaf shapes. Long days may induce basal leaves, but Bedigian observed a great deal of variation in expression of this character among cultivars grown in uniform nurseries in Kadugli, Sudan, and Urbana, Illinois, doubtless rooted in genotype. De Candolle (1829) viewed S. orientale as a mere variety of Sesamum indicum. De Candolle (1845) united Linnaeus’s species and chose the name S. indicum over its synonym, S. orientale. Thereafter, both scientific names were in use; the correct name has been a matter of discussion for decades (Manning 1991). Seegeler (1989) tenaciously made a case for S. orientale based on page precedence, arguing a taxonomic detail. The Tropicos database (Missouri Botanical Garden ) upheld S. orientale. However, Nicholson and Wiersema (2004) presented a new proposal to conserve S. indicum against S. orientale, arguing that they retrieved an overwhelmingly greater number of references using “Sesamum indicum” than “Sesamum orientale” in broad

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Internet database searches. Bedigian’s survey of hundreds of references in later publications confirms that nearly all articles used S. indicum, aside from those noting the synonymy. Weighing up the corpus of the literature, and for reasons similar to theirs, Bedigian decided decades ago to retain S. indicum. When a reviewer endorsed Seegeler’s (1989) arguments based on taxonomic priority in 2002, Bedigian (2003a, 2003b, 2004a) relented in subsequent publications. The debate was finally resolved by the Committee for Spermatophyta at the 2005 International Botanical Congress, where the International Code of Botanical Nomenclature (ICBN) formally approved the conservation of the name S. indicum L. (Brummitt 2005).

Methodology Label information was gleaned from herbarium specimens contained in the world’s collection of Sesamum L. held at the following herbaria (acronyms according to Holmgren et al. 1990): Africa: ADD, BOL, DAR, EA, J, KRT, MAK, PRE, WIND; Europe: B, BM, BR, BRLU, C, COI, G, HBG, K, LISC, LISU, M, P, S, W, WAG, Z; India: AHMA, AMH, BLAT, BSD, BSI, CAL, DD, DUH, IARI, MH, TBGT; United States: F, GH, MO, NY, PH, UC, US. Microsoft Access 2003 Relational Database Management System for Windows contains my database of specimens.

Botanical Description Sesamum comprises about 20 species, most of which are indigenous to tropical Africa, with two disjunct sections found in India. Published opinions vary, but botanists typically view the Pedaliaceae family, to which sesame belongs, to comprise 13 genera (Ihlenfeldt 2001) and an estimated 75 species of annual and perennial herbs. These occur mainly in the Old World tropics and subtropics, with the greatest number in Africa (Mabberley 1997; Purseglove 1968). Among these, sesame is the sole domesticated crop, a species of hot, dry climates, grown for its oil- and protein-rich seeds. Its oil is valued for its stability, color, nutty flavor, and resistance to rancidity. Milne-Redhead and Taylor (1956) described the Tanzanian specimen 9701, Kew (K) and East African (EA) herbaria, in a graceful summary: “Erect annual of very variable size, having yellowgreen stems that are obtusely square with grooves on the faces; leaves light green, paler and more gray below; some leaves are trisected; glands are yellow, the calyx pale green tinged purplish especially the lobes; corolla very pale mauve inside, deeper outside the tube and on the middle lower lobe; behind this deeper area very pale sulfur yellow and behind that fine purple spots on a pale mauve background surrounding a second yellow zone half way down the tube; filaments and style white, anthers light brown; pollen white.” Mkamilo and Bedigian (2007) offer additional details: stout, aromatic herb up to 2 m tall; root system with strongly tapering taproot up to 90 cm long, bearing many laterals.

Stem The stem is firm, square with ribs at each corner, and furrowed at the midpoint of each side, up to 3 cm in diameter at base, bright pale green, sparsely hairy to glabrous, with 4-celled glands present on all parts. Stem fasciation, an abnormal disruption of meristem activity that widens the stem and alters bud position, is common in many Sesamum spp. as well as among sesame cultivars.

Leaves Leaves are decussately opposite in lower parts, arranged spirally and 3-lobed to 3-foliolate in upper parts; stipules absent; petiole up to 17 cm long, grooved above, at least at the base; blade of lowest leaves ovate in outline, 10–21 cm × 5–13 cm, margin entire or partly toothed, higher leaves with narrowly elliptical lobes or leaflets 9–17 cm × 3–7 cm, margin entire or toothed, highest leaves

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Figure 2.8  Sesamum indicum cultivar having tetracarpellate capsules. South Farm, University of Illinois, Urbana, 1981. (Photo by the author.)

narrowly elliptical, 5–15 cm × 1–3 cm, margin entire. There is considerable variation in leaf shape, size, surface texture, and margins.

Flowers Flowers are generally solitary or in small fascicles in upper leaf axils, bisexual, zygomorphic, 5-merous, with 2 bracts at the base, each bract with an axillary gland; calyx with oblong lobes 4–7 mm × 1–1.5 mm, slightly fused at base, apex acute, long-hairy; corolla campanulate, 2–3.5 cm long, base slightly bent and widened, slightly 5-lobed, with lobes ca. 1 mm long, lowest lobe longer, white to violet, throat often yellow and spotted purple; stamens 4, inserted near base of corolla tube and included, the upper 2 shorter than the lower 2, with a staminode between the upper stamens; ovary superior, oblong-quadrangular, ca. 5 mm × 2 mm, grayish hairy. Style 1 cm long, with 2-lobed stigma.

Fruit Each fruit is an oblong-quadrangular capsule 1.5–4 cm long, hairy, with a short triangular beak at apex, gray-brown at maturity, loculicidally dehiscent, many-seeded; bicarpellate, but each carpel divided by a false septum almost to the apex; some cultivars are tetracarpellate (Figure 2.8). It takes about six weeks from anthesis to fruit maturity. Each plant produces a large number of seeds. The capsules open automatically when dry, causing the seed to scatter.

Seeds Seeds are flattened obovoid, 2–3 mm long, 0.5–1 mm thick, a flattened pear shape narrowly ridged all around (Figure 2.9), rather smooth in many instances, white, ivory, gray, tan, beige, brown, red, or black. Seeds of some cultivars are rugose (Bedigian survey 2009; Hiltebrandt 1932; Nohara 1933; Ram 1930); seedlings have epigeal germination. There are noticeable differences in seed shape,

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Figure 2.9  Seed of Sesamum indicum with narrow ridge around the circumference. (Scanning electron micrograph prepared by D. Bedigian, 1982.)

size, and surfaces among species in the genus Sesamum, rendering seed characteristics a useful trait for species determination. Hatanaka (1959) isolated oligosaccharides from the seeds: a trisaccharide, identified as planteose; and the tetrasaccharide fraction, a mixture of lychnose and a new isomer of it, for which he proposed the name sesamose. Wankhede and Tharanthan (1976) stated that sesame contains D-glucose, D-galactose, D-fructose, sucrose, raffinose, stachyose, planteose, and sesamose. Grougnet et al. (2006 and Chapter 4, this volume) reveal seed coat (testa) constituent details.

Functional Form: Glandular Trichomes A unique feature characteristic of sesame and other Pedaliaceae (Abels 1975; Beille 1909; Cronquist 1981; Hakki 1984; Ihlenfeldt 2001; Karatela and Gill 1984; Langham 1944, 1945; Langham and Cortes 1945; Mabberley 1997; Manning 1991; Metcalfe and Chalk 1950; Solereder 1908) is the plant surfaces being coated with minute, mucilage-filled, highly specialized outgrowths identified as glandular trichomes. The stalked glandular trichomes of Sesamum (Figure 2.10) are found on stems, leaves, flowers, and capsules and link the plant body to its environment. Each mature secreting glandular hair consists of four cap cells attached to a stalk of one to three cells, vividly described by Thomson and Healey (1984): “a foot cell that projects the bulbous head of the trichome above the epidermis.” Masses of these mucilage glands give the lower surface of leaves, stems, and capsules a grayish appearance from a distance, and under a hand lens impart a luminance to the surface dotted with glossy hairs (Bedigian 2004c). The structural design is a capitate tetrad of cells upon a well-anchored stem, forming a structurally sturdy unit. Together, the glistening stalked tetrads bestow a sheathing that hovers above the surface of the epidermis. They confer resistance against wilting in other species (Ehleringer 1984), insulate against heat, and protect against UV damage. They unquestionably reduce the leaf surface’s direct exposure to the sun, because as leaf pubescence increases, leaf reflectance also increases, resulting in decreased absorbance (Ehleringer 1984) and decreased heat load on the leaf. As does leaf rolling (Blum 1979), they effectively reduce the leaf area per plant, and possibly affect the

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Figure 2.10  Epidermal gland (trichome) of S. latifolium. (Scanning electron micrograph prepared by D. Bedigian, 1982.)

dynamics of leaf gas exchange. Through its increased light reflectance, pubescence has a significant effect on leaf temperature, photosynthesis, and water loss (Ehleringer 1984). After contact with water, accounts indicate that the outer cell walls of the four cells forming the head either burst (Abels 1975) or dissolve (Ihlenfeldt 2001), producing an enormous amount of mucilage used as an emollient, lubricant, soap, or shampoo (Bedigian 2003b; Bedigian and Harlan 1986; Beille 1909). Yetman and van Devender (2002) give details that the leaves and stems of closely related Proboscidea parviflora (Wooten) Wooten & Standley, Martyniaceae, are “covered with a mucilaginous substance that is hard to remove.” According to Ihlenfeldt (2001), the biological function of these unique structures is not yet defined. In Bedigian’s view, they play a role in maintaining turgor pressure, in the following ways. Sesame geneticist Derald G. Langham (1945) observed: “During a period of drought the varieties with many glands showed less wilting than the types with few glands. … [This] indicates that the number of glands is probably directly correlated with resistance to drought, and reciprocally correlated with resistance to excess water.” Jeffrey (1987) suggested that leaf hairs might have a special role in accumulating occult water ephemerally present as dew or mist: “The question is whether such water flows to the leaf surface for cuticular absorption or merely re-evaporates when the energy balance alters. Both these phenomena require further investigation.” Osmotically active constituents may reduce solar heating or evaporative loss (Hallahan et al. 2000). The production of slimy material that coats the plant surface may indirectly perform these functions. Gaff (1997) suggests that starch hydrolysis occurs during water stress, forming a vitreous barrier. Glenn et al. (1997) indicate that the resulting increased reflectance of leaves reduces transpiration. In Bedigian’s (2004c) view, their design enhances the plant’s chances of survival. The glands enable the plant to withstand severe desiccation without tissue death. Their architecture contributes masses of knob-like surfaces exposed to ambient air that increase exposure in three

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Figure 2.11  Pollen grains close to the surface of the dehiscent anther of S. orientale var. malabaricum Nar. (Scanning electron micrograph prepared by D. Bedigian, 1982.)

dimensions, enabling air passage for capture of fugitive desert humidity and reducing transpiration, thus minimizing water loss.

Growth and Development Germination of sesame seed is moderately slow, and seedlings grow slowly until they reach a height of 10 cm; thereafter, growth is rapid. Branches develop when the plant is about 25 cm tall. The degree of branching is cultivar-specific, and non-branching cultivars exist. Roots of single-stemmed cultivars generally elongate more rapidly than those of branched ones, while the latter spread more quickly. Growth habit is generally indeterminate. Flowers arise in leaf axils on the upper stem and branches, and the node number on the main shoot at which the first flower is produced is a highly heritable cultivar characteristic. Most flowers open at dawn, wilt after midday, and drop at dusk. Pollen shed (anthesis) (Figure 2.11) occurs just before the flowers open (Khidir and El Awad 1972), hence most fertilization is cleistogamous. The stigma is receptive one day before flower opening and remains receptive for another day. Under natural conditions, pollen (Figure 2.12) remains viable for 24 hours. Flowers are mostly self-pollinated, but cross-pollination is possible, and under exceptional conditions may reach 68% (Yermanos 1980). Depending on the cultivar, the crop matures 70–150 days after sowing. Capsules near the stem base normally ripen first; those nearest the tip ripen last (Figure 2.13). Active dry matter accumulation and synthesis of oil occur 12–24 days after fruit set, but continue at a reduced rate up to 27 days after, with a slight fall in oil content before maturity. The free fatty acid percentage is highest at the beginning of synthesis, and declines rapidly around 18–22 days and then more gradually until seed maturity. In most cultivars, dry mature fruits split open and seeds are shattered.

Synergistic Sesame Lignans The lignans sesamin and sesamolin, antioxidant compounds not found in other edible oils, are significant functional constituents of sesame seeds. Strain (Hemalatha and Ghafoorunissa 2004; KamalEldin 1993; Kang et al. 2000, Kang et al. 2003; Namiki 1995) coupled with location grown, aging, and frost damage (Beroza and Kinman 1955) affect the sesamin, sesamolin, and sesamol content of

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Figure 2.12  Pollen grain of S. indicum. (Scanning electron micrograph prepared by D. Bedigian, 1982.)

Figure 2.13  Flowers of S. indicum open from base to apex. South Farm, University of Illinois, Urbana, 1981. (Photo by the author.)

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sesame seed. Families most closely related to Pedaliaceae, the Bignoniaceae and Acanthaceae, also contain sesamin (Bedigian et al. 1985). Sesamin and sesamolin are antioxidants (Budowski and Markley 1951; Seino et al. 1981) that enable sesame oil to resist oxidative rancidity, an action attributed to the methylenedioxyphenyl group. Haller et al. (1942) found in the course of testing pyrethrum extracts in combination with a number of vegetable and fish oils that sesame oil markedly increased the effectiveness of pyrethrum insecticides. Nowadays, sesamin and sesamolin are active ingredients in antioxidants, antiseptics, bactericides, viricides, disinfectants, moth repellants, and anti-tubercular agents, uses identified in many patents. Bedigian (2000, 2003a, 2000b, 2003c) has reviewed their beneficial use in traditional healing. Namiki (1995) assessed the synergistic effects of sesame lignans on vitamin E activities when added to tocopherols. Chapters of this volume by Grougnet et al., Kamal-Eldin, Mak, Chiu, and Ko, Shahidi and Tan, and Sacco and Thompson review the newest details.

Ecology of Sesame and Various Wild Relatives Sesame is a crop of the tropics and subtropics, but summer planting and newer cultivars have extended its range into more temperate regions. It occurs mainly between 25° S and 25° N, but grows up to 40° N in China, Russia, and the United States, 30° S in Australia, and 35° S in South America. Sesame is sensitive to low temperatures, and for this reason it generally grows between sea level and 1500 m. Sesame is a short-day plant, but certain cultivars have become adapted to alternative photoperiods. Sesame’s sensitivity to photoperiod prevented many tropical lines from flowering in Urbana (40° N). With 10-hour days, flowering generally begins 42–45 days after sowing, although certain Turkish cultivars flower after just 37 days (Bedigian 1984). Temperature and moisture have major modifying effects on the number of days to flowering. High temperatures are required for optimal growth and production. Temperatures around 30°C encourage germination, initial growth, and flower formation, but specific cultivars tolerate up to 40°C. Temperatures below 20°C normally delay germination and seedling growth, and temperatures below 10°C inhibit both. Established plants can withstand high moisture stress, but seedlings are extremely susceptible. Sesame produces an excellent crop with a rainfall of 500–650 mm, in preference evenly distributed during the growth season. Sesame is very susceptible to waterlogging. Ideally, 35% of the rain should fall during germination until first bud formation, 45% until main flowering, and 20% at seed filling. Rain should cease as first capsules begin to ripen. Heavy rain at flowering drastically reduces yield. After stem elongation, it is also susceptible to wind damage. Sesame thrives on moderately fertile and well-drained soils with pH ranging from 5.5 to 8.0, and most cultivars are sensitive to salinity. Sesame’s ability of self-pollination makes sense for situations where there is a low supply of resources available, such as limited soil moisture and nutrients. If fewer pollinators are available, self-compatibility is an evolutionary advantage. Reduced flower size brings anther and stigma in close proximity and is an advantage in dry habitats for such dryland species as these. The genus Sesamum and related Pedaliaceae show an exceptionally wide adaptability and environmental flexibility. Species of Sesamum exhibit extraordinary success in occupying empty places where few other herbaceous dicotyledons survive. They are vigorous in formerly cultivated fields; they thrive on nutritionally poor soils and sites where moisture is in short supply. They seem to tolerate heat and drought well and are not demanding, growing in gravel, sand, and rocky roadside rubble. Weedy is the best adjective to describe the genus. This opportunistic ability to colonize abandoned cultivation suggests that the conservation status of this genus is unharmed—indeed, it may even be improved—by human enterprises, as expansion into human-made habitats allows it to thrive. Sesamum species are extremely successful colonizers that have a tendency to take hold, occasionally even to become invasive. In the field, one often encounters wild Sesamum spp. in swarms. Bedigian observed (1979) swarms of S. orientale var. malabaricum Nar. along the roadside at the Aarey Milk Colony, outside Mumbai (Figure 2.14).

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Figure 2.14  S. orientale var. malabaricum Nar. (Photographed at Aarey Milk Colony outside Mumbai, India.)

Sesamum angolense Welw. grows in dense monoculture in western Tanzania and Uganda, sometimes in stands of several acres, along unpaved rural roads (Bedigian fieldwork 1999). In many locations, S. angolense was the dominant flowering plant aside from grasses; it was able to aggressively colonize and successfully degrade the rocky/gravelly substratum. In northern Darfur, well beyond the limit of rainfed agriculture, S. alatum Thonn. flourished in monoculture (Bedigian fieldwork 1999), the only flowering plant aside from grasses, for dozens of kilometers in the region. Bedigian observed camels ripping the plants from the ground and devouring them whole: stems, leaves, flowers, and roots (Bedigian 2004c). S. angustifolium (Oliv.) Engl. grows in zones with slightly higher rainfall, in Darfur as well as many regions in Tanzania; it also shows that swarming habit. S. latifolium Gillett thrives on granitic outcrops: there are thick stands on rocky outcrops in Talodi, in the southern area of the Nuba Mountains of Sudan to jebel outcrops in eastern Sudan, close to the Ethiopian border south of Gedaref, in seriously inaccessible locations (Bedigian and Harlan 1983). Despite their shattering tendency, as a family the Pedaliaceae have adaptations for holding back some seeds and delaying germination. The woody seed-containing capsules do not open fully; an angular pocket at the base of the capsule retains some seed when the capsules open. Sesame’s woody capsules, constructed with membranous septa that partition the chambers, hold seeds tightly. Therefore, despite the well-known shattering habit of the genus, a few seeds in each capsule remain tightly held, thereby preserving them for favorable germination conditions. Seed dispersal methods seem to correlate with the habitat of each species. For example, in Sesamum alatum, winged seed aid dispersal, in the driest habitats, enables dissemination to suitable locations. S. angustifolium has tiny, lightweight seed, more easily dispersed in savannah grasslands. S. angolense and S. latifolium have larger, heavier seed that can store a larger quantity of food reserve, and do not disappear into the stony, gravelly substrata; their woody capsules enables seed retention for more favorable season and prolongs dispersal. Wild Sesamum spp. and related genera have dormant seed. Testae of the wild relatives examined contain chemical inhibitors that retard germination, requiring drastic measures in the laboratory

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(Bedigian 1981, 1984); in nature, rainfall is needed in sufficient quantity to wash the inhibitor away, thereby protecting the species under unfavorable growth conditions. Nabhan et al. (2000) describe a similar germination delaying response in the related genus Proboscidea (Martyniaceae). These germination-delaying mechanisms occur to the extreme in species of other genera of Pedaliaceae, such as Rogeria adenophylla Gay ex Delile and Harpagophytum procumbens (Burch.) DC. ex Meissn., which also have needle-sharp spines and thorny grapple hooks, respectively, on their indestructible woody capsules, which protect against animal or insect feeding; the capsules, difficult to open, secure seeds powerfully.

Phenotypic Variation of Cultivated Sesame An evaluation of the sesame crop must consider the regions from which the sesame plants that show the greatest morphological distinctiveness derived. Any barrier to gene flow (altitude, temperature, rainfall, soil, and social and political isolation) permits populations to fragment and accumulate genetic differences in the subpopulations (Baker 1953; Dobzhansky et al. 1977; Harlan 1970; Stebbins 1950). When a location is isolated in space and time, a secondary center of diversity has time to evolve (Harlan 1975). Much overlooked meticulous morphological delineations by Hiltebrandt (1932), Nohara (1933), and Ram (1930) offer well-illustrated details of the respective geographic areas they drew from: the former Soviet Union, Japan, and India, respectively. The vast diversity in Sudan’s Nuba Mountains (Bedigian 1981, 1988, 1991; Bedigian and Harlan 1983) should be viewed as a microcenter, or secondary center, of diversity. Kobayashi (1986) endorsed this outlook. Recent molecular studies (Abdellatef et al. 2008; Ali et al. 2007; Bhat et al. 1999; Laurentin and Karlovsky 2006) also characterize these differences. “Patterns of Morphological Variation in Sesame” (Bedigian et al. 1986) reports the numerical analysis of three years of field observations at the South Farm, University of Illinois, Urbana. The study was rooted in the complete USDA gene bank collection. A large portion of that assemblage is material amassed by the plant explorer Jack R. Harlan in Afghanistan, Ethiopia, India, Iran, Iraq, Pakistan, and Turkey, increasing the base world collection. Donations from China, Korea, Sudan, and Thailand supplemented that foundation. Detailed morphological data were derived from 92 measurements replicated from 353 accessions representing 20 countries; highly correlated entries were removed by analysis. Factor analyses and principal components analyses tested the final 32 independent characters for each sample, using programs deliberately customized for the huge data matrix by renowned innovative statistician David L. Swofford. Included among the cultivars were equivalent data about the proposed progenitor, the var. malabaricum (PI 490267), to investigate its placement in the assemblage. These procedures led to the first classification of a world collection of sesame’s diverse genetic resources (Bedigian 1984; Bedigian et al. 1986) held in the USDA gene bank. Scatter plots, dendrograms, and a 3-dimensional principal factor analysis grid depict the categorizations; Figure 2.15 displays those groupings. J. Trevor Williams, editor of the Plant Genetic Resources Newsletter, described these analytic techniques as landmark research, among the first ever to apply principal components analysis to detect the relationships of variations in a crop: “The results showed patterns of geographic and ecological races, and the paper is well worth reading on methods of analysis” (Williams 1987). Likewise, using AFLP markers, Ali et al. (2007) found “close genetic relations between the accessions” associated with geographical origin. Their accessions, primarily from East Asia, clustered in two main groups “mainly corresponding to their geographical origin as well as morphological characteristics.” Their results showed, as ours had, that “tetra-carpals characters appears mostly in accessions belonging to Japan and Far East countries, whereas those belonging to other Asian countries produced bi-carpals. Results of cluster pattern showed a relationship when comparing molecular and morphological data for most of the phenotypic characters.”

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Group 1 Group 3 Group 4

Group 5

Group 6

Group 2 Group 7

Group 8

Figure 2.15.  Relationships between sesame cultivars in the USDA world sesame collection generated from principal component scores and factor analysis scores of sesame cultivars subjected to the grouping procedure (Adapted from Bedigian, D. 1984. Sesamum indicum L. Crop origin, diversity, chemistry and ethnobotany. Ph.D. dissertation, University of Illinois, Urbana-Champaign. University Microfilms DA8502071, Dissertation Abstracts International 45, 1985: 3410-B; and Bedigian, D., C.A. Smyth and J.R. Harlan. 1986. Economic Botany 40: 353–365.)   Group 1, tetracarpellate plant types, farthest from all other forms. Recessive yellow-green plant color, tall plant height, few branches, mainly simple and trifoliate leaves with low pubescence, often with large foliar appendages along the petiole, and many nodes to first flower. Compact inflorescence.   Group 2, first branch of the bicarpellate group consists of ca. 35 cases that are mainly of Indian origin and have a distinct purple tinge. The crop’s progenitor sorts with this group. Dominant genotype, purplish, tall plants, many branches and frequent secondary branching, large number of nodes to first capsule, diffuse inflorescence with short, bicarpellate capsules, late maturity; small flower size, deep purple corolla color with heavy yellow color behind the lip of the corolla, and dark yellow corolla throat. Leaves primarily entire; foliar appendages entirely absent, leaf margins are untoothed. Blue-green plant color, low pubescence.   Group 3, mainly Turkish plants, with a natural diversity reflected by lack of complete homogeneity in the cluster pattern. Some general trends among Turkish cases are early maturing, low, bushy plants bearing pubescent bicarpellate capsules and primarily entire leaves.   Group 4, primarily Korean cases, and shows considerable uniformity. Erect, monostem tall plant types with no or few robust branches; strap-shaped leaves with foliar appendages, capsules borne 3/node and condensed compactly along the stem; capsules have long beaks. Corolla white, long; corolla throat dark yellow, a second yellow region behind the lip. Otherwise, the corolla lacks purple pigmentation associated with other groups. Foveola deep yellow, with little pubescence. Tripartite leaves are blue-green with dentate margins. These cultivars also cluster away from the dominant purple genotype on the dendrogram.

Sesame Seed Color Relative to Oil Content An easy approach to predicting oil content in sesame would be to seek out a relationship between seed coat color and seed composition. Parthasarathy and Kedharnath (1949) stated that black and brown seeds contain more oil, but that oil from white seeds is superior in quality. However, a study in the Sudan of 20 exotic and 26 local strains of sesame of various seed colors did not confirm any of these contradictory claims: that is, it seems that there is no relationship between seed color and oil content or quality (El Tinay et al. 1976; Khidir 2007; Khidir pers. comm. 2009). Some accounts from India (Krishnamurthy et al. 1959, 1960) indicated that black seeds contain more protein, followed by brown and white types in descending order. Again, a study in the Sudan did not confirm these findings (El Tinay et al. 1976). Yermanos et al. (1972) examined 472 lines from the USDA’s world sesame collection and found that early cultivars had higher oil content than medium or late plants. Earliness, yellow seed color, and large seed size correlated with lower iodine values; also, earliness and yellow seed color correlated with high oleic and low linoleic acid content. Yermanos et al. (1972) did not report any strong association between seed color and oil content. Tashiro et al. (1990), testing 42 strains of Japan’s collections, reported that white seeds in their study had higher oil content, significant at the 1% level. Were et al. (2006) checked 30 accessions from East Africa and found that white seeds produce the highest oil content. Note that unlike Yermanos et al.’s (1972) review of a world germplasm collection, the later studies examined small

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samples of locally available material from East Asia and East Africa. A distinguished deviation from the generalization that cultivars with white seed contain more oil is the renowned “red sesame of Kordofan” grown throughout the Nuba Mountains of Sudan, prized for its high oil content, substantially greater than local white-seeded cultivars (Bedigian and Harlan 1983). It is oversimplification to generalize from two narrow findings drawn from small sample sizes to every sesame cultivar of a particular seed color. White-seeded cultivars of Kenya are not genetically or morphologically identical with white-seeded cultivars of Korea, China, or Japan. That would ignore multi-gene complexities (Khidir and Ali 1971) and the real geographic clusters of morphological differences that we documented (Bedigian et al. 1986). A recent study of seed color inheritance in sesame (Falusi 2007) sums up “the complex nature of the expression of this trait. Results also indicated that plants with the same seed color might be under different genotype constitution.”

Sesame Domestication Genetic studies indicate that cultivated sesame derives from wild populations native to the Indian subcontinent: the western Indian peninsula and parts of Pakistan. Bedigian (1984, 1988, 1998, 2000, 2003a, 2003b) and associates (Bedigian et al. 1985, 1986) showed that sesame’s progenitor is a taxon named Sesamum orientale var. malabaricum Nar. (John et al. 1950) comprising a group of wild and some weedy forms native to the Indian subcontinent. It was illustrated even in the pre-Linnaean period, in Hortus Malabaricus (Burmann 1679), as Car-elu (Figure  2.16). It displays close morphological, genetic, and phytochemical affinities to the cultivar Schit-elu (Figure 2.17). It remained obscure even among Indian botanists. N.C. Nair named a synonym Sesamum mulayanum Nair (1963), unaware of the previous designation (Bedigian 2003a, 2003b; Nair pers. comm. 1979). Sesame and this wild form share the same diploid chromosome number, 2n = 26 (Annapurna Kishore Kumar 2003; Annapurna Kishore Kumar and Hiremath 2008; Hiremath and Patil 1999; John et al. 1950; Kawase 2000; Mitra and Biswas 1983; Thangavelu 1994), and the diagnostic

Figure 2.16  Car-elu illustration of the sesame crop’s progenitor, in Hortus Malabaricus. (From Burmann, J. 1679. Hortus Malabaricus. J. Schreuderem, Amsterdam.)

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Sesame: The Genus Sesamum

Figure 2.17  Schit-elu, pre-Linnean illustration of sesame in Hortus Malabaricus. (From Burmann, J. 1679. Hortus Malabaricus. J. Schreuderem, Amsterdam.)

criterion of domestication: fertile hybrid products of reciprocal crosses (Harlan 1992) have been achieved (Bedigian 1984, 1988, 2003a, 2003b). Independently, Hiremath and Patil (1999), Kawase (2000), Bisht et al. (2004), Annapurna Kishore Kumar (2003), and Annapurna Kishore Kumar and Hiremath (2008) repeated those crosses, and each team found the offspring of these reciprocal crosses to be fertile. Agreeing with Bedigian (fieldwork 1979, 2003a, 2003b) and Kawase (2000), Annapurna Kishore Kumar is convinced from side-by-side morphological comparisons of specimens of S. orientale var. malabaricum and S. mulayanum that they are a single taxon. Additionally, Bhat et al. (1999) and Nanthakumar et al. (2000), using RAPD markers, demonstrate proximity of S. indicum to this progenitor. New results from molecular phylogeny analyses, using the two chloroplast DNA regions that have been widely used in the Lamiales (ndhF and trnLF), along with material determined by this author, confirm that Sesamum indicum and S. orientale var. malabaricum are most closely related (Olmstead pers. comm. 2010). These tests and independent results provide unassailable evidence of the domestication of sesame. Aware that many writers had considered Africa the place where sesame originated, Bedigian made an effort to complete identical experiments: interspecific crosses and lignan analyses (1984, 1988, 2003a, 2003b, Bedigian et al. 1985) to assess Sesamum latifolium, 2n = 32, the African progenitor proposed by Ihlenfeldt and Grabow-Seidensticker (1979). Repeated attempts to make reciprocal crosses (Bedigian 1984, 1988, 2003a, 2003b; Sudanese scientists M. Hassan pers. comm. 1999, 2003; M.O. Khidir pers. comm. 1980, 2009; and M.A. Mahmoud pers. comm. 1979, 1999, 2003) were unsuccessful, yielding only a few shriveled seeds. Since the diploid chromosome numbers of the two species are mismatched, this is not surprising. Investigation of Sesamum lignans showed qualitative differences between those two species (Bedigian 1984, 1988, 2003a, 2006; Bedigian et al. 1985) too. Whereas both lignans, sesamin and sesamolin, are present in the crop as well as in the

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designated progenitor, the absence of sesamolin in S. latifolium (Bedigian et al. 1985; Kamal-Eldin 1993; Chapter 3, this volume) casts additional doubt about its proximity to domesticated sesame. While it is accurate that most species of Sesamum and genera of Pedaliaceae are native to Africa, no botanical study has ever substantiated an African progenitor from which sesame arose. Seeking a correct answer, not wedded to any view, this writer has searched the literature for decades without finding a shred of scientific work to support domestication in Africa. We confidently dismiss that oft-repeated assertion. As Katz notes in “Propagation of Errors in Review Articles” (2006): “Frequent repetition can turn fictional breakthroughs into common lore.” Errors, repeated often enough, can become convincing, accepted facts.

Biogeography and Crop Movements It is beyond the scope of this volume to present an analytic record regarding angiosperm biogeography and past continental movements (Raven and Axelrod 1974; Schuster 1972) that may have played a role in species dispersals. The genus Cucumis (of African origin) has ca. 30 African and 20 Asian species (Renner pers. comm. 2009). Cucumber (Cucumis sativus L.) is of Asian origin and was domesticated in Asia, although the earliest divergence events in Cucumis likely took place in Africa (Renner et al. 2007; Renner and Schaefer 2008; Schaefer et al. 2009). Eggplant, too, is an example of a crop domesticated in Asia, while derived from an African section of Solanum (Furini and Wunder 2004; Isshiki et al. 2008; Meyer pers. comm. 2009; Sakata and Lester 1997; Sekara et al. 2007; Stàgel et al. 2008). Another instance of such disjunction is the narrow Asian and widespread African distribution of the genus Barleria, in the Acanthaceae (Balkwill and Balkwill 1998).

Sesamum Systematics Misconstrued The systematics of Sesamum has its origins in pre-Linnaean literature—as an example see Figures 2.16 and 2.17, in Hortus Malabaricus (Burmann 1679)—and classifications of the genus have varied widely. Much of the very limited recently published literature about sesame genetic resources is replete with error. There are a number of reasons for this. Original descriptions, floras, and morphological descriptions published in diverse languages may have been inaccessible to other workers lacking translations. Some, complaining about inability to obtain the published literature, have resorted to conjecture to close gaps. Much of the recent literature on sesame biodiversity consists of “review articles,” and often one reviewer copied a previous rundown uncritically, perpetuating errors. This section reviews some of the difficulties chronologically. The sole published monograph (Joshi 1961) omits a majority of African species. Thereafter, many other writers, unfamiliar with species in the genus, but desirous of organizing the information, have filled the literature with speculation instead of refined, substantiated detail, perpetuating confusion and errors in the literature. In Nayar and Mehra’s oft-cited review (1970), Table 7, titled Sesamum Species, Their Chromosome Number and Distribution, fails to methodically reference the original publication for each species reported; it lists many synonyms as independent species. A particularly problematic sentence in the narrative incorrectly identifies “two species which show the widest distribution, S. capense and S. schenckii”; Table 7 omits the species S. alatum entirely; it lists distribution of S. capense and S. schenckii in tropical Africa and India; S. capense also in Australia. Table 8 refers inexplicably to “S. capense (2n=26) (as S. alatum)” and S. schenckii (2n=26) (as S. grandiflorum).” Without explanation or substantiation, they generated synonymy between S. alatum and S. capense . Nayar and Mehra (1970) offered a lengthy provisional synthesis in the section headed Origin of Sesame conjuring several possible routes of passage, and wrote: “Portères (1950), for instance, suggested that sesame probably arose through hybridization with S. alatum (now S. capense) and S. radiatum and that even the related Ceratotheca sesamoides might have gone into the formation of some of its races”; but Nayar and Mehra did not represent Portères’ view accurately. In fact, Portères

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(1950) stated, much more provisionally, “Il est possible”: “It is possible that the cultigene species that we know could have been [soit] derived from several other species.” In the last paragraph, Portères “suggest[ed] that they are residues, relicts of a more generalized former exploitation and regressed with the arrival of Eastern sesame.” This is correct, aside from the fact that in Portères’ view the Eastern (orientale) sesame arose in East Africa. Portères, working from inexact linguistic and morphological evidence (Hilu and de Wet 1977), gave his opinion that the co-occurrence of “the vile companion weed, S. radiatum with cultivated sesame in the East and the African center would lean toward a hearth in Eastern Africa.” Note, however, that Bruce’s taxonomic review of the family Pedaliaceae (1953) for Flora of Tropical East Africa explicitly states that S. radiatum does not occur in East Africa. Concurrently, Gillett (1953) described the new species Sesamum latifolium, which Portères (1950) would not have known. Portères (1962) hypothetically classified various cradles of crop domestication based on poorly known taxonomic and biogeographic affinities, hence somewhat perplexingly, and includes S. indicum, S. alatum, and S. radiatum as cultivated oil crops in the Nilotic region. We cannot know for certain what species Portères was actually referring to, since he cited no voucher specimens in either publication. However, this confusion has consequences that have persisted in the sesame literature. Further details continue in the species descriptions below. It was necessary to translate the existing taxonomic literature from French, German, Portuguese, and Spanish, and to find appropriate help for translations from Japanese by specialists, to comprehend of all the views presented and to detect the sources of confused species names. Indian and Japanese scientists did most of the cytogenetic studies in the first half of the 20th century. Unfortunately, those cytogenetic reports too lack the herbarium voucher specimens that define the taxa investigated. For example, the cytological study of S. capense (Kobayashi and Shimamura 1951) lacks a voucher specimen, although they reported that they obtained seed from Pretoria. The species list in Kobayashi’s final review, “Cytogenetics of Sesame” (1991), as others before it, has problems with identifications that Bedigian’s forthcoming taxonomic revision shall clear up. For example, he treated S. ekambaramii as a synonym of S. capense, whereas careful literature review, herbarium study, and field observations indicate that it is a synonym of S. alatum. As regards S. grandiflorum, the original source, Abraham (1945), is only an abstract, and Abraham demurred, without confirming identification or any further details when I asked about it during our meeting in India in 1979. Kobayashi (1991) puzzlingly gave the East Indies as a second location for S. schinzianum Aschers. and its chromosome count as 2n = 64, citing Kobayashi (1981); but in actuality that source, Kobayashi (1981), indicates “Chromosome No. unknown.” Two photographs sent to this author by Makoto Kawase of a species he identified S. schinzianum are, in fact, S. radiatum (Figures  2.25 and 2.26), which sheds light on that mystery and suggests that other authors, too, may be using that name mistakenly, because S. schinzianum is restricted to Namibia. Further studies about S. schinzianum, such as Fukuda et al. (1988) and Hiremath et al. (2007), are also problematic: since no voucher specimens are given, the identifications probably are not verifiable. This confusion has added consequence because in later studies Yamada et al. (1993) used those names to describe chloroplast DNA variation in four species of Sesamum including S. capense, which indeed belongs in section Sesamopteris but is re-identified by Bedigian as Sesamum alatum based on Kobayashi’s notes about distribution: the S. capense referred to occurs only in southern Africa, whereas Kobayashi (1991) reported the distribution of the taxon in India, Africa, and Australia. In either case, Yamada et al.’s finding supports our view of the section Sesamopteris’s remoteness from the rest of the genus, with reasons discussed in the next section. Another study, by Hiremath et al. (2007), refers to S. capense from Cameroon, far out of the geographic range of that taxon. These unverifiable names prevent us from obtaining an accurate interpretation of their results. None of these authors cited herbarium voucher specimens, spotlighting the indispensable reason for doing so (Bedigian 2004b) to ensure that subsequent researchers can be sure which taxa are tested.

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An evaluation of the published literature regarding Sesamum cytogenetics and interspecific hybridization reveals that it, along with the taxonomy of the genus, is badly in need of rectification. For this volume, we consider the genus in terms of the gene pools (GP) delineated by Harlan (1951, 1992; Harlan and de Wet 1970). By definition, the crop and its progenitor are joined in GP-1; in cases where wide crosses are possible between a wild species and the crop, that species is added to GP-2; hybrid union of a wild species with the crop using extreme measures, such as use of colchicine, radiation, or other mutagens, places that species in GP-3. Bedigian’s presently forthcoming taxonomic revision of the genus Sesamum provides a synopsis, synonymy, comprehensive biogeographic detail, species distribution maps, taxonomic key and revision of sections. Therefore, a thorough discussion of evolutionary relationships of these species is beyond the scope of this chapter.

Sections of Sesamum L. Section Sesamum Article 22 of the International Code for Botanical Nomenclature stipulates that the autonym Sesamum for the section repeat the genus name, and that it contain the same species that is the type for the entire genus. That happens to be the cultivated Sesamum indicum L. in our case. Following Harlan (1992; Harlan and de Wet 1970), the GP-1 includes the crop plant sesame and the crop’s progenitor, identified as S. orientale var. malabaricum (John et al. 1950; Bedigian 1984, 1988, 1998, 2000, 2003a, 2003b; Bedigian et al. 1985, 1986). A revision of the current section Sesamum as defined by Ihlenfeldt and Grabow-Seidensticker (1979), containing S. latifolium, is required. Bedigian’s forthcoming taxonomic revision will assign the new circumscription. Bygone botanists such as Bryant (1783), Roques (1809), and Eberhardt (1909, 1911) had figured its origin correctly. Chromosome Number 2n = 26 (Annapurna Kishore Kumar 2003; Annapurna Kishore Kumar and Hiremath 2008; Hiremath and Patil 1999; John et al. 1950; Kawase 2000; Mitra and Biswas 1983; Thangavelu 1994).

Section Chamaesesamum Benth. On the Indian subcontinent, this unique prostrate section Chamaesesamum currently holds two species, S. laciniatum Klein ex Willd. and S. prostratum Retz., characterized by seeds without wings and with testa foveolate (minutely pitted) (Figure  2.18). Writers as early as Hooker (1885) commented that the two species are very similar in appearance, aside from the lacy, deeply incised leaves of the former. Clearly, with its prostrate habit, section Chamaesesamum has distinctive appearance and growth pattern. The capsules are leathery and open with difficulty, thereby retaining seeds. It seems prophetic that Bedigian urged (1981) collection of Sesamum in India: “Threats of extinction, desertification of agricultural lands and increasing tendency to monoculture will soon eliminate these rich genetic resources.” By 2005, Bedigian’s survey of locations south of Chennai where S. prostratum had been collected previously found very little remains of those riches. Beachfront housing development and commercial mega-parks have replaced those habitats, reduced further by the tragic 2004 Indian Ocean tsunami. Chromosome Number 2n = 32 (Bose and Biswas 1994; Mitra 1985; Raghavan and Krishnamurty 1945; Ramanujam 1941, 1942; Ramanujam and Joshi 1948).

Section Sesamopteris Endl. Seeds having thin membranous wings characterize this African branch. Sesamum alatum typifies section Sesamopteris.

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Figure 2.18  S. prostratum Wight (1850) in Icones plantarum Indiae Orientalis.

Sesamum alatum Thonn. Botany Erect annual herb up to 1.5 m tall, with simple or sparsely branched stem, glabrous but with mucilage glands. Leaves opposite, lower ones palmately divided or lobed (Figure  2.19), upper ones simple; stipules absent; petiole 1–7 cm long; leaflets or lobes of lower leaves lanceolate, central one longest, up to 8 cm × 2 cm, often with undulate margin, blade of upper leaves linear to lanceolate, 3–10 cm long. Flowers solitary in leaf axils (Figure 2.20), bisexual, zygomorphic, 5-merous; pedicel short, with a nectary at base; calyx campanulate with narrowly triangular lobes ca. 3 mm long, densely glandular, deciduous; corolla obliquely campanulate, 2–3 cm long, slightly 2-lipped, pink or purple, inside sometimes red-spotted, pubescent; stamens 4; disk fleshy, conspicuous; ovary superior, hairy, 2-celled, style filiform, stigma 2-lobed. Fruit a narrowly obconical capsule up to 5 cm × 0.7 cm (Figure 2.21), base gradually narrowed, apex with beak up to 12 mm long, 4-grooved, dehiscing longitudinally, many-seeded. Seeds obconical, ca. 2.5 mm × 1.5 mm, with a large, 2–3-mm-long wing at apex and 2 shorter wings at base, testa with honeycomb-like structure, pale to dark brown. Ecology and Geographic Distribution Sesamum alatum occurs in dry savannah and is often common around villages, sometimes tolerated as a weed in fields. It is often found on sandy soils, in riverbeds, grassland, and open bush, or as a weed in fields, often in cultivated sesame. Sesamum alatum is widely distributed in tropical Africa, occurring in dry regions from Senegal to South Africa. It is an introduced weed in India. It is not in danger of genetic erosion. Sesamum alatum represents a biogeographical rarity: it is established both north of the equator, across the Sahel zone, and south of the equator, in Namibia, South Africa, and Zimbabwe. Extremes of its collection are 29° S, Lebowa, South Africa (van der Maesen 4618, K) and 22° N, Wadi Agilhog (Allaqi) Egypt (Murray 507, K). Only ca. 70 species display such an N-S disjunction along the arid corridor (de Winter 1971).

Cultivated Sesame and Wild Relatives in the Genus Sesamum L.

Figure 2.19  S. alatum. view_plant?pi=11390&cat=V)

(Drawing

courtesy

Jean

Lehmann.

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http://www.metafro.be/prelude/

Figure 2.20  S. alatum flower. (Photo courtesy Bart Wursten, Malilangwe Wildlife Reserve, Zimbabwe http://www.zimbabweflora.co.zw/speciesdata/species.php?species_id=152520, http://www.zimbabweflora. co.zw/speciesdata/image-display.php?species_id=152520&image_id=1)

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Figure 2.21  S. alatum capsules. (Photo courtesy Bart Wursten, Malilangwe Wildlife Reserve, Zimbabwe http://www.zimbabweflora.co.zw/speciesdata/species.php?species_id=152520, http://www.zimbabweflora. co.zw/speciesdata/image-display.php?species_id=152520&image_id=2)

Uses Leaves, flowers, and young shoots of Sesamum alatum collected from the wild provide a vegetable when cooked, sometimes flavored with its pounded seeds (Bedigian 2004c). The seed oil is an aphrodisiac and cures diarrhea and other intestinal disorders (Bedigian 2003b, 2004c). Branches of the leaves and flowers are a delicacy to camels (Bedigian 2003c), and promote fertility in them, as recounted in the market at El Fasher, Sudan. Properties The seed oil has about 5% unsaponifiable matter: lignans (2-episesalatin 1.4%, sesamin 0.01%, sesamolin 0.01%), sterols (22%) and tocopherols (210–320 mg/kg oil) (Kamal-Eldin, Chapter 3 this volume; Kamal-Eldin and Appelqvist 1994; Kamal-Eldin et al. 1994). In our survey (Bedigian et al. 1985), Sesamum alatum and S. triphyllum, both in section Sesamopteris, lacked sesamin and sesamolin, a fact which has phytotaxonomic significance. Ono et al. (2006) described S. alatum as deficient in (+)-sesamin. Prospects Sesamum alatum may remain a minor vegetable, of local importance in drier areas. Chromosome Number 2n = 26 (Kedharnath 1950; Prabakaran 1996a, 1996b). Vernacular Names Simsim al jumal; simsim al ghazal (Arabic).

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Section Aptera Seidensticker This writer agrees with Ihlenfeldt (1994) that sections Aptera and Sesamopteris pose difficult taxonomic problems. In both sections, there are a number of well-defined species of mostly restricted distribution, as well as large, widespread complexes of closely related species. These complexes exhibit a wide range of morphological and ecological variation and show a gradation of characteristics between well-defined species. A thorough analysis of distinguishing characteristics, along with their geographic distributions, reveals that numerous transitional forms make taxonomic treatment difficult. Suites of characters shared by forms in section Sesamopteris are entwined, defying clear delineation. According to Ihlenfeldt and Grabow-Seidensticker (1979), Sesamum rigidum is the ancestor of the African group they identified as section Aptera Seidensticker. Its lignan fingerprint is presently unknown. To resolve its relationship in evolution, seeds collected by Bedigian require study. Species in this section, Sesamum angolense, S. angustifolium, and S. calycinum Welw., resemble one another in many ways, and in our earlier study, all three species had both lignans sesamin and sesamolin (Bedigian et al. 1985). Kamal-Eldin (1993) reported these results for S. angustifolium too, and elaborates this topic in Chapter 3, this volume. Sesamum angolense Welw. Botany Erect annual or perennial herb up to 3 m tall, strong scent, with a simple or branched, slightly quadrangular stem. Leaves opposite, simple, without stipules, sessile or with a short petiole (Figure 2.22); blade oblong, elliptical to oblanceolate, 2–11 cm × 0.5–4 cm, base cuneate, apex truncate, retuse or acute and usually mucronate, margin entire, more or less inrolled, glabrescent above, white tomentose and densely glandular below. Flowers solitary in leaf axils, bisexual, zygomorphic, 5-merous; calyx campanulate (Figure 2.23), with lanceolate lobes up to 1 cm × 2 mm, pubescent, persistent in fruit; corolla obliquely campanulate, up to 7 cm long, 2-lipped, pink, red, purple, or pale mauve with deeper markings, pubescent; stamens 4, filaments arising from a band of hairs near the base of the corolla tube; disk annular, regular; ovary superior, white-hairy, 2-celled, style filiform, stigma 2-lobed. Fruit a slightly quadrangular capsule 2–3 cm × 5–7 mm, 4-grooved, gradually narrowed into a flattened short beak, densely pubescent but glabrescent, dehiscing longitudinally, manyseeded. Seeds flattened obconical, ca. 2 mm × 1.5 mm, not winged, faintly rugose. Ecology and Geographic Distribution Sesamum angolense is common in grassland, open woodland, roadsides and abandoned fields, on black or red loam soil, at 400–2400 m altitude. Sesamum angolense is widespread and not in danger of genetic erosion. Sesamum angolense occurs in the Democratic Republic of Congo, Rwanda, Burundi, Kenya, Uganda, Tanzania, Malawi, Zambia, Angola, Zimbabwe, and Mozambique. Prospects Sesamum angolense is a minor vegetable, of importance when other vegetables are scarce. Its medicinal properties deserve more attention, along with research on the nutritional composition of the leaves. Uses Sesamum angolense leaves gathered from wild plants are mixed with legumes and other edible leaves; the sauce forms a slimy product (Bedigian 2004c) served with a staple cereal such as maize or millet. In Malawi, Sesamum angolense is beneficial to women, babies, and invalids (Jansen 2004a). A decoction or infusion of the leaves or roots is drunk to counteract vomiting, cough, catarrh, constipation, diarrhea, and poisoning, and applied externally to cure wounds and skin diseases such as measles and sores, and to curtail bleeding after tooth removal (Bedigian 2003b, 2004c; Kokwaro

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A

D

B

Seasamum angolense Welw. A Flowering plant. B Flower cut lengthwise. C Lower part of the flower cut lengthwise. D Stigma. E Cross-section of every. C E

J. Fleischmann del.

Figure 2.22  S. angolense in Thonner (1915). The introduction to Franz Thonner’s (1908) Die Blütenpflanzen Afrikas, thanks to Joseph Fleischmann, a Viennese artist who did most of the illustrations in these large tomes, basically a detailed key to African plant families and genera. That is the original source of the Sesamum angolense illustration.

1993; Tredgold 1986; Watt and Breyer-Brandwijk 1962; Williamson 1955). Formerly, in Malawi, the leaves were pounded with water and the liquid poured into the eyes and over the ears, nose, and mouth to cure smallpox. In Malawi an infusion of the roots is drunk at the time of labor to hasten delivery. An infusion of the leaves in water is used also as a shampoo to oil and straighten the hair and as a substitute for soap. The leaves can also be dried and stored for later use, either whole or powdered. Properties The seed of Sesamum angolense contains the phenylpropanoid sesamin, and sesangolin, a related compound (Jones et al. 1962; Potterat et al. 1988). Its high lignan content offers opportunities for developing the oil as a synergist to pyrethrin insecticides (Jansen 2004a). Chromosome Number 2n = 32 (Kedharnath 1950).

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Figure 2.23  Sesamum angolense is recognizable by its leaves, which are entire, leathery, and white tomentose below, and by its large showy flowers. Synonym Sesamum macranthum Oliver (1875). Tab. 84 illustrating S. macranthum is reproduced here.

Vernacular Name Mlenda (Swahili). Sesamum angustifolium (Oliv.) Engl. Botany Erect or spreading, simple or branched herb, up to 2 m tall, with a grooved, quadrangular, glabrescent stem. Leaves opposite, simple, without stipules, almost sessile; blade linear-lanceolate, 2–12 cm × 0.1–4 cm, base cuneate, apex acute or rounded, margin entire, undulate or sometimes in lower leaves irregularly toothed, thinly pubescent to glabrous above, usually densely glandular below. Flowers solitary in leaf axils, bisexual, zygomorphic, 5-merous; calyx campanulate with lanceolate

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lobes up to 9 mm long, persistent in fruit; corolla tubular, 2–4 cm long, 2-lipped, pink, red, mauve, or purple, often spotted inside, pubescent; stamens 4, filaments arising from a band of hairs in the corolla tube; disk annular; ovary superior, 2-celled, style filiform, stigma 2-lobed. Fruit a narrowly oblong, quadrangular capsule up to 2.5 cm × 4 mm, deeply 4-grooved, apex with a narrow beak up to 3.5 mm long, glabrous to slightly pubescent, dehiscing longitudinally, many-seeded. Seeds ca. 1.5 mm × 1 mm, not winged, surface rugose, black. Sesamum angustifolium belongs to section Aptera, along with Sesamum angolense and Sesamum calycinum (Grabow-Seidensticker 1988; Ihlenfeldt 1988). The difference between Sesamum angustifolium and Sesamum calycinum is not always clear (Bedigian, firsthand observations; Jansen 2004b). The fruits of Sesamum calycinum are usually broader, and its seeds slightly larger with a double fringe. Ecology and Geographic Distribution Sesamum angustifolium is common on roadsides, in grassland, and as a weed in cultivated fields, from sea level up to 2000 m. It is widespread and not in danger of genetic erosion. It occurs in Kenya, Sudan, Tanzania, and Uganda, but its distribution area may be larger because its distribution is adjacent to that of the closely related and very similar Sesamum calycinum. Uses The leaves and young shoots of Sesamum angustifolium (and S. calycinum) are gathered from the wild, but they are also a weed tolerated in home gardens (Bedigian 2004c). The mucilaginous leaves and flowers are cooked with other ingredients such as other leaf vegetables (various species in Luo villages in western Kenya), and legumes, to thicken sauces that are eaten with the staple cereal ugali (maize or millet porridge). The taste is mild and slightly sour, and nowadays it is less fashionable, and considered a hardship food by residents of towns. The leaves and young shoots can be dried and stored for later use. The seeds contain some oil, and are eaten in a sauce or soup after crushing. In Kenya the plant is fed to cattle, mixed with sweet potatoes to make digestion easier (Jansen 2004b). The leaf mucilage is used to treat eye troubles, burns, wounds, stomachache, and diarrhea in children, and to ease labor and delivery (Bedigian 2003b, 2004c; Katende et al. 1999; Kokwaro 1993). A root decoction treats cough, and an infusion of powdered roots is drunk to cure diarrhea and other intestinal disorders. Crushed leaves are used as a soap substitute, rubbed into the hair when washing it to give it a glossy look, but also to treat baldness. The slimy crushed leaves trap tsetse flies on cattle, a fresh application giving protection for about 4 hours. The seed oil is used to treat ringworm. Properties While no study has been undertaken to investigate leaf constituents specific to Sesamum spp., Latham (1965) observed: “Traditional use of certain wild green leaves are rich sources of carotene, ascorbic acid, iron and calcium; they contain useful quantities of protein and it is highly desirable that rural peoples continue to eat them.” The seed of Sesamum angustifolium yields about 30% oil, which is pale to dark yellow and odorless. The oil contains 3.7% unsaponifiable matter, of which 16% are lignans (Kamal-Eldin and Appelqvist 1994; Kamal-Eldin et al. 1994). Prospects Sesamum angustifolium is a vegetable appreciated in eastern Africa, both cultivated and widely available from the wild. Its nutritional composition and medicinal properties deserve further research. Chromosome Number 2n = 32 (Nakamura and Sato 1956; Renard et al. 1983). Vernacular Names Mfuta, mlenda mwitu (Swahili); onyulo, anyim (Luo).

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Section under Scrutiny S. radiatum Schumacher and Thonner Botany Erect annual woody herb 30 to 120 cm tall. Stem simple or branched, glandular pubescent, malodorous. Leaves not divided, heteromorphic: the lower petiolate (petioles up to 2.5 cm long), lanceolate to ovate, coarsely serrate, up to 6 x 3.5 cm (Figure 2.24); upper bracts lanceolate or cultrate, mealy glandular on lower surface. Leaves mainly ovate, often coarsely serrate, entire; rugose, pilose, and thick (Figure 2.25), with a deep green color. Flowers axillary and solitary. Corolla 3.5–5 cm long, obliquely campanulate (Figure 2.26), purplish to white; exterior of corolla has a greenish hue, which, when mixed with the purple cyanins contained in other cells, gives it a brownish appearance. Capsules narrowly oblong in lateral view, 2.5–3 x 0.8–1 cm, pubescent and densely glandular, with short broad bifid beak that usually splits upon maturity into two short biapiculate points. Seeds 2.5–3 x 1.7–2 mm, rugose or pitted, with sculptural lines radiating perpendicular to the edge all around the margin of the seed faces, black or brown (Bedigian 2004c, 2004d, 2005, 2006a, 2006b; Dokosi 1969; Ihlenfeldt 1988).

Figure 2.24  S. radiatum. (Reproduced by permission from Wageningen Agric. Univ. Papers, 90–91 (Stevels 1990), drawn by Will Wessel-Brand.)

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Figure 2.25  S. radiatum plant habit. (Photo courtesy Makoto Kawase, Kyaito Township, Mon State, Myanmar, 2004.)

Figure 2.26  S. radiatum flower detail. (Photo courtesy Makoto Kawase, Kyaito Township, Mon State, Myanmar, 2004.)

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Figure 2.27  Photo of Ceratotheca sesamoides, Burkina Faso. (Courtesy Prof. Dr. Ir. L.J.G. van der Maesen, professor of plant taxonomy, Biosystematics Group, and National Herbarium of the Netherlands, Wageningen University.)

Abels (1975) suggested three phenotypes of S. radiatum based on capsule morphology, and indicates relatedness to Ceratotheca. Each variant displays an increasingly bifid beak on the capsule, from absent to 1-mm-long points, to 2–3-mm-long horns. Stevels (1990) endorses the close relationship between S. radiatum and Ceratotheca. Ihlenfeldt and Grabow-Seidensticker (1979) depict their section Aptera as linked to the genus Ceratotheca (Figures 2.27–2.29). Ecology and Geographic Distribution African origin, now found throughout the tropics, in India, Sri Lanka, on the Malaysian peninsula, in Sumatra, and on North Borneo (Stevels 1990). Distributed throughout West Africa (excluding Mauritania and Niger), Central Africa, and limited to Angola in southern Africa; cultivated occasionally in Sudan and Tanzania (Bedigian 2003b, 2004c, 2004d; Stevels 1990). As stated above, Bruce’s assessment of the Pedaliaceae (1953) explicitly states that S. radiatum does not occur in East Africa, undoubtedly conferring with Gillett (1953) about his new species description, Sesamum latifolium. Andrews (1956) listed S. radiatum, albeit imprecisely described, in southern Sudan, its distribution only in Equatoria province. Broun and Massey (1929) had also previously recorded S. radiatum with a similarly ambiguous description, specifying only another southern province, Bahr al Ghazal (Jur). No herbarium specimens record those specimens. Therefore, it is still uncertain whether S. radiatum occurs in South Sudan. It is widespread in neighboring Congo and westward (Bedigian, 2003b, 2004c, 2006); in savannah areas of Nigeria and North Cameroon, it is cultivated (Bedigian 2004d), and grows as a common roadside weed as well. Uses The fresh leaves are often used as spinach, in soup, and in sauces eaten with porridge (Bedigian 2004c, 2004d), the plant mucilage is used for medical purposes (Bedigian 2003b, 2004d), and the

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Figure 2.28  Ceratotheca sesamoides courtesy of PROTA Programme, Wageningen University, the Netherlands. (Reproduced by permission from Wageningen Agric. Univ. Papers, 90–91 (Stevels 1990), drawn by Will Wessel-Brand. http://database.prota.org/PROTAhtml/Photfile%20Images%5CLinedrawing%20 Ceratotheca%20sesamoides.gif)

Figure 2.29  Ceratotheca triloba roadside, Kunene, Namibia, March 2006. (Photo by the author.)

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seeds are consumed whole, toasted, ground into a paste, or extracted for oil. The seeds are occasionally an adulterant of sesame crushed for oil; sometimes it is cultivated for seeds, instead of S. indicum, as reflected in its local African name black beniseed. A cold infusion of macerated fresh young leaves facilitates childbirth (Bedigian 2003b, 2004d; Dokosi 1969). Leaf infusions kill head lice. A filtrate of crushed leaves is drunk and leaf macerate used in bathing to treat metrorrhagia (uterine bleeding at irregular intervals not associated with expected menstrual periods). It is an antidote for scorpion stings, and is applied externally to sprains. Properties The seed contain 32.3% oil (Dalziel 1955, citing Manlove 1932). The seed oil contains the phenylpropanoid lignan sesamin (Bedigian 1988, 2003a, 2003b; Bedigian et al. 1985). Chromosome Number 2n = 64 (John and Rao 1941; Sampath and Ramanathan 1949). Vernacular Names Black beniseed, a name used interchangeably with that of S. indicum; ridin barewa, ridin bareyi, and karkashin bareyi (Hausa)—terms loosely applied to wild species of Sesamum; ěku gogoro, ěkukù gogoro (including any wild form of Sesamum [Yoruba]) (Bedigian 2004d; Dalziel 1955; Irvine 1969). Sesamum latifolium Gillett Botany Gillett’s original description (1953) placed Sesamum latifolium in section Sesamotypus, a section defined by Bentham (1876) as having seeds without wings. Plants become woody as they mature. Erect herb with fetid odor, 60–180 cm tall, stems woody, quadrangular, sulcate, densely pubescent with a few spiky hairs, purplish green. Often many-branched. Leaves heteromorphic, ovate to trilobate, lower ones long-petiolate, ovate-cordate or 3-lobed with dentate margins, 8–13 cm long, 9–18 cm broad, cordate at base. Upper leaves smaller, 0.5–5 cm purplish petiole, leaves ovate to ovate-lanceolate, 2–5 cm long, 0.7–4 cm broad, sub-truncate or cuneate at the base, inconspicuously to coarsely serrate to crenate margins, acuminate at the apex; pubescent. Bracteoles conspicuous, pale brown, narrowly lanceolate, pubescent. Extrafloral nectaries yellow, turning brown as plants mature. Calyx deciduous, lobes narrowly lanceolate, acuminate, 5 mm long. Corolla cylindrical to conical; thinly pubescent and glandular outside, 2.5–2.8 cm long; white to pale pink or mauve, except for yellow flavonoid streak at midpoint of the interior and occasional purple flakes or spots; several deep purple lines on the lower lip (Figure 2.30) and pink shading near the base of the corolla. Filaments glabrous. Ovary pubescent, narrowly oblong, 6 mm, gradually narrowing into the style. Pedicels 1.5–3 mm long. Capsule densely pubescent, oblong-quadrangular, 4-grooved, 2.3–2.6 cm long, 0.5 cm broad, unilaterally gibbous with acute knobby protuberances at the base, rather abruptly narrowed into a short beak at the apex, 5 mm long. Seed 3 mm long, 2 mm broad, face foveolate, structures spread radially to the edge, sides deeply pitted, margins sharply angled. Early in Bedigian’s study, Ihlenfeldt and Grabow-Seidensticker’s (1979) identification of Sesamum latifolium as the progenitor of the crop sparked an interest in a detailed examination of this taxon (Bedigian 1981). Correspondence between Gillett and Bedigian about S. latifolium, and subsequently, following Bedigian’s 1979 fieldwork in Sudan, conversations with Gillett at the Kew herbarium, convinces her beyond any doubt that the specimens she studied in Sudan were those of Sesamum latifolium. The East African Herbarium, Nairobi, retains a copy of Gillett’s letter to Bedigian within the S. latifolium folder. Studies reported in the previous section about domestication by Bedigian (1984, 1988, 2003a; Bedigian et al. 1985; Bedigian et al. 1986), confirmed independently

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Figure 2.30  Sesamum latifolium flower, Nuba Mountains, Sudan. (Photo by the author.)

by others, lead us to reject Ihlenfeldt and Grabow-Seidensticker’s proposal of Sesamum latifolium as the crop’s progenitor. Scientists have referred to Sesamum latifolium incorrectly in much literature (Bedigian 2006a), naming it Sesamum radiatum (Kamal-Eldin 1993; Khidir 1962; Mahmoud et al. 1995). That error is ongoing: e.g., Hiremath et al. 2007. Kamal-Eldin notes the correct identification in Chapter 3, this volume. Ecology and Geographic Distribution Ihlenfeldt and Grabow-Seidensticker’s (1979) distribution record is incomplete. Bedigian observed S. latifolium growing on granitic outcrops in Eastern Sudan south of Gedaref, along the Ethiopian border, in the Nuba Mountains as far as south of Talodi, near El Obeid, west as far as west Zalengei, Darfur, and on heavy clay soils near Agadi in central Sudan (Bedigian 1981, 2004d; Bedigian and Harlan 1983; Bedigian 46, 47, 48, 59, MO). Uses None Properties The seed oil contains the phenylpropanoid lignan sesamin (Bedigian 1988, 2003a, 2003b; Bedigian et al. 1985; Kamal-Eldin 1993; Kamal-Eldin and Appelqvist 1994; Kamal-Eldin et al. 1994). See Kamal-Eldin, Chapter 3 in this volume, for additional details. Chromosome Number 2n = 32 (Grabow-Seidensticker and Ihlenfeldt 1979).

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Vernacular Names Simsim al culb (“dog’s sesame”), simsim al marfayeen (“wolf’s sesame”) (Bedigian and Harlan 1983).

Genetic Relationships Determined by Interspecific Hybridizations After the decades from the 1930s to the 1950s, when records of most chromosome numbers were registered (Bolkhovskikh et al. 1969), there was little work on cytogenetics of Sesamum apart from a few reviews, until the last decade of the 20th century. Many inaccuracies, due to inaccurate transfer of available data, lack of familiarity with the taxa named, and uncritical copying without attribution of sources, appeared in those review articles. S. alatum and S. capense were allied, incorrectly (Nayar and Mehra 1970), and based on published geographic distributions, it appears that the identifications are incorrect; the name S. occidentale is a synonym used for both S. indicum and S. radiatum, rendering putative interspecific hybrids pointless. Here we emphasize the significant support that cytological and hybridization studies by Hiremath and Patil (1999), Kawase (2000), Annapurna Kishore Kumar (2003), and Annapurna Kishore Kumar and Hiremath (2008) lend to Bedigian’s placement of the var. malabaricum in GP-1, with the crop, described fully in the section about domestication, above. Hybridization by drastic methods place S. alatum (Parani et al. 1997; Prabakaran 1996a, 1996b; Rajeswari and Ramaswamy 2004; Tarihal 2003) and S. prostratum (Raghavan and Krishnamurty 1947; Ramanathan 1950; Ramanujam 1942, 1944) in GP-3. Ganesh Ram et al. (2006) repeated those studies with similar findings, but obtained no capsule formation or seed set in hybridization attempts with S. radiatum. Similarly, Mazzani (1961, 1964) and Prabakaran et al. (1992) obtained no seed. Dasharath et al. (2007) used drastic methods to rescue those aborted hybrid embryos, permitting placement in GP-3. Lee et al. (1991) reported capsules but no seed in crosses between the crop and both S. alatum and S. radiatum. Falusi et al. (2001) report interspecific hybrids between Sesamum indicum L. and Ceratotheca sesamoides by drastic measures; this places the latter, too, in GP-3, supporting the views of earlier taxonomists (Abels 1975; Ihlenfeldt and Grabow-Seidensticker 1979; Stevels 1990) about the close relationships between the two genera.

Sesame Genetic Resources in Gene Banks Sesame is rich in genetic variability. The matter of gene bank cooperation and policies varies markedly from place to place. The USDA supplies seeds for research, 50 per accession requested; from Australia, seed is available to clients throughout the world. It is often difficult to get up-to-date information from gene banks. There are sensitivities about data ownership and intellectual property— concerning, for example, how and for what purpose seeds are to be used, and what constitutes adequate credit. Gene banks’ funding is limited, and there are an inadequate communications infrastructure and insufficient staff to handle enquiries in a timely manner. There is a paucity of information available, suggesting that genetic resources of sesame are at risk. All this is more acute for a crop such as sesame, which is neglected overall, and this calls for some action (Bedigian 1981, 2003a; Bedigian, Chapter 1, this volume). PROTA (Mkamilo and Bedigian 2007) reports the following curated collections: the National Bureau of Plant Genetic Resources, New Delhi (India), maintains about 10,000 sesame accessions, including 2500 accessions from outside India; the Institute of Crop Science (CAAS), Beijing (China) with 4100 accessions; the N.I. Vavilov All-Russian Scientific Research Institute of Plant Industry, St. Petersburg (Russian Federation), with 1500 accessions; the National Genebank of Kenya, KARI, Maguga (Kenya), with 1325 accessions; the Centro Nacional de Investigaciones Agropecuarias (CENIAP-INIA), Maracay (Venezuela), with 1250 accessions; the Plant Genetic Resources Conservation Unit, USDA-ARS, Griffin, Georgia (United States), with 1200 accessions.

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The collections contain many duplicates, and smaller core collections of well-identified and wellevaluated material appear appropriate.

Germplasm Resources and Policies: The Example of Ethiopia Teklewold, Amde, and Baye, authors of “Sesame cultivation in Ethiopia,” Chapter 18 of this volume, kindly provided the details included here for illustration. Ethiopia’s Institute of Biodiversity Conservation (IBC) collects, characterizes, and conserves genetic resources in Ethiopia. IBC holds 439 lines of sesame, of which 266 are local accessions while the remaining 173 are exotic, maintained by sesame breeders at the Melka Worer Research Center. To ensure that the country and its community obtain a fair and equitable share from the benefit arising out of the use of genetic resources, Ethiopia recently prepared regulations about access to genetic resources (Proclamation No. 482/2006, 2006). According to this law, for all except members of local communities, collection, acquisition, transfer, or use of genetic resources is possible only with written permission of IBC and after signing an appropriate access agreement. The access holders must meet stated obligations, including that they must prohibit transfer of the genetic resource to a third party, share the benefit that may be obtained from the utilization of the genetic resource, and uphold property rights and bar patent application without written consent of IBC. Even when in compliance with preconditions in the law, germplasm may be exported abroad only when it is impossible to carry out the intended research in Ethiopia. Policy regarding germplasm exchange between countries, institutions, or individuals is not explicit in the proclamation, but a multilateral system of access to germplasm resources to which Ethiopia is a party shall be in acquiescence with prior agreement.

Conclusions A modern taxonomic revision of Sesamum is essential and forthcoming (Bedigian manuscript). Cladistic analysis should move us towards a more definitive account of the genus’s complex taxonomy. The lignans of Sesamum show phytotaxonomic significance. A review of phytochemistry of every species will provide a significant tool for understanding relationships and evolution with in the genus and between genera in Pedaliaceae. Aside from hybrids relating to domestication, interspecific hybrids between the crop and various wild species of Sesamum have thus far been successful only when extreme measures are used. Their value in crop improvement is largely unproven, except for the attempts made with var. malabaricum. Embryo culture techniques that can rescue hybrid embryos may be useful. There is a need to represent the taxa studied in the existing, discordant literature about chromosome numbers and interspecific hybridization attempts with herbarium voucher specimens in order to establish the record conclusively.

Acknowledgments Early studies were funded by the Agronomy Department, University of Illinois, Urbana-Champaign. A Knight Foundation grant and Faculty Development award from Antioch College supported field observations in Kenya during the summer of 1993. The Botany Department and Institute for Advanced Study at Maseno University, Kenya, welcomed this researcher for nine weeks in residence during July–August 1994, allowing field surveys in western Kenya backed by a Faculty Development award from Antioch College. National Geographic Society Research and Exploration Grants #6218-98 and NGS #773204 financed fieldwork and herbarium study in Africa and herbarium study in Europe and India. Deepest thanks to Sudanese breeder Mahmoud Ahmed Mahmoud, who has encouraged my search

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of sesame in Sudan since its inception, offered suggestions about locations, and showed sustained interest in this survey. The Sudan Ministry of Agriculture Khartoum, the sesame research station Gedaref, and many colleagues at the Agricultural Research Corporation centers in El Fasher, El Obeid, Nyala, and Wad Medani set field study in motion. The National Museum of Kenya, Tanzania Commission for Science and Technology, Uganda Council for Science and Technology, and Namibia’s Ministry of Environment and Tourism and its National Botanical Research Institute facilitated parts of this research. Particular thanks to Mary Seely, Desert Research Station, Windhoek, and to Coleen Mannheimer, National Botanical Research Institute, who provided counsel and enthusiasm for the undertaking, and to biologist Keith Leggett, whose generous invitation to visit his Desert Elephants project permitted a survey in remote Kaokoland. Appreciation to each of many herbarium keepers and curators for permission to review their rich collections, used to create my ACCESS database of Sesamum and Ceratotheca spp. Librarians at the Leonard Lief Library, Lehman College, CUNY; Olive Kettering Library, Antioch College, Yellow Springs, Ohio; Greene County Public Library, Xenia, Ohio; Missouri Botanical Garden, St. Louis; and the University of Illinois, Urbana-Champaign, provided assiduous reference support for this study. Many colleagues advanced completion of this chapter: Dan Austin, book review editor, Society for Economic Botany, and Marshall Sundberg, editor, Plant Science Bulletin, serve the botanical community with valuable discussion forums through book reviews, and have processed several hundred book reviews by this researcher, providing new food for thought; Edward Kennelly and students in the Phytochemistry Laboratory, Biology Department, Lehman College, CUNY, supplied stimulating suggestions; Norman Farnsworth, professor of Pharmacognosy, University of Illinois, Chicago, generously granted access to the NAPRALERT database; Henning von Gierke, Clinical Professor Emeritus, Department of Aerospace Medicine, Wright State University School of Medicine, Beavercreek, Ohio, helped to clarify a number of ponderous German phrases; Paul Bordoni, Cary Fowler, and Luigi Guarino, IPGRI, Rome, provided information and insight about gene bank collections; Kazue Okamoto, teaching assistant, Kyoto Seika University, in 2005, and evolutionary/molecular biologist Tomoko Y. Steen, research specialist, Science Reference Division, Library of Congress, in 2009, carefully searched and translated critical passages from several of Kobayashi’s publications in Japanese for clarification; Suzanne Renner, Department of Biology, University of Missouri, St. Louis and director of the Botanische Staatssammlung and the University Herbarium, Munich, and Rachel Meyer, New York Botanical Garden, offered details about phylogeny in Cucumis and Solanum, respectively. I am extremely grateful to Richard Olmstead, professor of biology and herbarium curator, Burke Museum, University of Washington, Seattle, who shared the results of his investigations of Pedaliaceae molecular phylogeny, and to L.J.G. van der Maesen, professor of plant taxonomy, Biosystematics Group and National Herbarium of the Netherlands, Wageningen University, who answered nomenclatural questions, provided type descriptions and illustrations unavailable in U.S. libraries, and appraised the manuscript critically.

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Studies on 3 Chemical the Lignans and Other Minor Constituents of Sesame Seed Oil Afaf Kamal-Eldin Contents Introduction....................................................................................................................................... 79 Sesame Oil Lignans..........................................................................................................................80 Sterols...............................................................................................................................................84 Tocopherols....................................................................................................................................... 85 Hydrocarbons.................................................................................................................................... 85 Flavor Compounds............................................................................................................................ 86 Pigments............................................................................................................................................ 86 Minor Components and Stability of Sesame Oils............................................................................. 86 Minor Components and Chemical and Physiological Effects of Sesame Oils................................. 87 Acknowledgments............................................................................................................................. 88 References......................................................................................................................................... 88

Introduction The oil fraction of most oilseeds is composed mainly of triacylglycerols (95–99%) acting as a dispersing medium for a wide range of lipophilic and amphiphilic secondary metabolites, collectively forming what is known as the unsaponifiable fraction. Sesame (Sesamum indicum L.) oil consists of triacylglycerols (95%), diacylglycerols (2.6%), free fatty acids (0.1%), and other lipids, including phospholipids and unsaponifiables (2.3%). Sesame oil fatty acid composition includes mainly the following acids: oleic (35–50%), linoleic (35–50%), palmitic (2.3–6.8%), and stearic (7.0–16.7%) (Kamal-Eldin et al. 1992 and references cited therein; Kamal-Eldin and Appelqvist 1994a). The unsaponifiable fraction is obtained by extraction in a lipophilic solvent after saponification of acyl lipids (Kamal-Eldin 2005). Oil from the only cultivated species, Sesamum indicum, contains 1.2–1.8% unsaponifiables. Oils from the wild species studied contained higher percentages, e.g., S. alatum Thonn., 4.2–4.9%, S. latifolium Gillett, 2.3– 2.7%, and S. angustifolium Engl., 3.3–3.7% (Kamal-Eldin et al. 1992; Kamal-Eldin and Appelqvist 1994a). Note that in these early publications, we incorrectly named S. latifolium as S. radiatum. In most vegetable oils, the major part of the unsaponifiable fraction contains phytosterols; but sesame seed oil, where lignans are the major components, is an exception (Kamal-Eldin et al. 1991). Scientific interest in the unsaponifiable fraction of sesame oil stems from several aspects: (i) lignans can be used as markers of the authenticity of the oil, its botanical source (chemotaxonomy), and the degree of processing causing losses and transformations, (ii) many of these components, mainly tocopherols and tocotrienols, are important antioxidants responsible for the stability of the oil, and 79

80

Sesame: The Genus Sesamum

(iii) lignans are currently being recognized for having interesting physiological bioactivities with regard to inhibition of chronic diseases, and phytosterols are also being appreciated as cholesterollowering agents. This chapter reviews the main components of the unsaponifiable fraction of sesame seed oil and their unique chemical properties. Physiological effects of the oil appear in Chapters 13, 14, and 15 of this book.

Sesame Oil Lignans Sesame seed oil is especially interesting because of high contents of biologically active furofuran lignans (Budowski and Markley 1951; Budowski 1964; Moazzami and Kamal-Eldin 2006). Most plant lignans are rather polar and several are glycosylated, but sesame seed is unique for its oilsoluble lignans, sesamin and sesamolin (Figure 3.1), which are the main non-acyl constituents of O

OMe

O

HO

O

O H

H

H

H O

O

OH

OH (+)-Pinoresinol OMe 2, 6-bis-(3-methoxy-4-hydroxy phenyl)cis-3, 7-dioxabicyclo[3.3.O]-octane

OMe (+)-Piperitol 2-(3-methoxy-4-hydroxy phenyl)- 6-(3, 4methylenedioxy phenyl)-cis-3, 7dioxabicyclo[3.3.O]-octane

O

O

O

O

O H

O H

O

H O

H O

OH OMe (+)-Sesamolinol 2-(3-methoxy-4-hydroxy phenoxy)- 6-(3, 4methylenedioxy phenyl)-cis-3, 7dioxabicyclo[3.3.O]-octane

O O (+)-Sesamin 2, 6-bis-(3, 4-methylenedioxy phenyl)-cis3, 7-dioxabicyclo[3.3.O]-octane

O O O H

H O

O O

(+)-Sesamolin O 2-(3, 4-methylenedioxy phenoxy)- 6-(3, 4methylenedioxy phenyl)-cis-3, 7dioxabicyclo[3.3.O]-octane

Figure 3.1  Structures and biosynthetic pathway of (+)-sesamin and (+)-sesamolin in sesame seeds (modified from Kato et al. 1998).

81

Chemical Studies on the Lignans and Other Minor Constituents of Sesame Seed Oil O O O

HO

O HO

O

CH2OH O

OH

O

H

CH2OH O O OH OH

OH

O

O

CH2OH

CH2OH HO

H

H

O O

O O

O

(+)-Sesaminol triglucoside Sesaminol 2 -O- -Dglucopyranosyl (1 2)-O-[ -Dglucopyranosyl (1 6)]- -Dglucopyranoside

OH

O

O

O OH

O

H O

HO

O

CH2 HO

(+)-Sesaminol diglucoside Sesaminol 2 -O- -D-glucopyranosyl (1 2)-O- -D-glucopyranoside OH

OH

MeO O

MeO O HO

CH2OH OH

O

HO

O H

H

CH2OH OH

OH

O

CH2 OH

O

H

H O OMe

OH

OMe

O

O

HO

OH

O

HO

CH2OH O O OH

OH

OH

(+)-Pinoresinol diglucoside-1 Pinoresinol 4 -O- -Dglucopyranosyl (1 2)-O- -Dglucopyranoside

(+)-Pinoresinol diglucoside-2 Pinoresinol 4 -O- -D-glucopyranosyl (1 6)-O- -D-glucopyranoside

Figure 3.2  Structures of lignan glucosides in sesame seeds.

its oil (Budowski and Markley 1951; Budowski 1964). These lignans appear in sesame seed oil and are not known to be present in other parts of the plant (Nagabhushanan et al. 1956). Sesame seed lignans are biosynthesized from (+)-pinoresinol, which is formed by stereo selective coupling of two molecules of conferyl alcohol in the presence of a dirigent protein, that is, a protein that dictates the stereochemistry of a compound synthesized by other proteins (Davin et al. 1997; Davin and Lewis 2003; Jiao et al. 1998; Kato et al. 1998; Marchand et al. 1997a, 1997b). In addition to sesamin and sesamolin, high levels of sesaminol tri- and diglucosides and low levels of sesamolinol and pinoresinol diglucosides (Figure 3.2) are present in sesame seed meals (Katsuzaki et al. 1992, 1994; Moazzami et al. 2006a, 2006b), but the variations in levels are not well established. It is also unknown how glucosylated lignans relate biosynthetically to sesamin and sesamolin. There are also significant qualitative and quantitative differences between cultivated and wild Sesamum species. Bedigian (1988; Bedigian et al. 1985), using thin layer chromatography, showed that seed oils of S. angolense Welw., S. angustifolium, and S. calycinum Welw. have both lignans, and that S. latifolium and S. radiatum Schum. and Thonn. contain sesamin but not sesamolin, while S. alatum and S. capense Burm. f. are void of sesamin and sesamolin. Subsequently, we found that S. alatum contains low levels of sesamin and sesamolin when analyzed by high performance liquid chromatography (HPLC), a more sensitive technique (Kamal-Eldin and Appelqvist 1994b; KamalEldin et al. 1994; Moazzami and Kamal-Eldin 2006). Levels of sesamin and sesamolin comparable to those in S. indicum were reported in S. radiatum and S. schinzianum Aschers. (Fukuda et al. 1988; Kamal-Eldin and Appelqvist 1994b; Kamal-Eldin et al. 1994). Other lignans are also present in some wild species. For example, sesangolin (Figure 3.3) is present in the seed oils of S. angolense (Jones et al. 1962) and S. angustifolium (Kamal-Eldin et al. 1994), and 2-epi-sesalatin

82

Sesame: The Genus Sesamum O

O

O

O O

O H OMe

H

HO

O

H

H

OH

O

OH

O O

OH

(+)-Sesangolin 2-(3, 4-methylenedioxy phenoxy-6-methoxy phenyl)- 6-(3, 4-methylenedioxy phenyl)-cis3, 7-dioxabicyclo[3.3.O]-octane

(+)-2-Epi-sesalatin 2-epi-(3, 4, 5-trimethyoxy phenyl)- 6-(3, 4methylenedioxy-5-methyoxy phenyl)-cis-3,7dioxabicyclo[3.3.O]-octane

Figure 3.3  Structures of (+)-sesangolin and (+)-2-episesalatin; lignans present in oils of some wild Sesamum species.

(Figure 3.3) is present in very high levels in S. alatum (Kamal-Eldin and Yousif 1992; Kamal-Eldin and Appelqvist 1994b). Table 3.1 shows wide ranges of variation in the contents of sesamin and sesamolin in Sesamum indicum oils: 1,550–18,600 mg/kg for sesamin and 1,230–10,600 mg/kg for sesamolin (Beroza and Kinman 1955; Fukuda et al. 1988; Hemalatha and Ghafoorunissa 2004; Kamal-Eldin and Appelqvist 1994b; Tashiro et al. 1990). Like other secondary metabolites in plants, lignan levels may vary according to cultivar, cultivation location, and agro-climatic conditions. Beroza and Kinman (1955) studied the effects of strain and location on the levels of sesamin and sesamolin in S. indicum seed oils. In 33 strains, sesamin ranged from 3,400 to 11,300 (7,000 ± 1,800 mg/kg), and sesamolin ranged from 1,400 to 5,900 (4,100 ± 800 mg/kg). Analysis of variance showed that the sesamin levels (coefficient of variation (CV) = 26.3%) were more subject to variation than were the sesamolin levels (CV = 19.4%). Tashiro et al. (1990) studied the effect of seed color types on oil and lignans of 42 Japanese sesame strains. There was a significant difference in the sesamin content of sesame seeds with reference to seed color (P = 0.05) but not for sesamolin. The variations Table 3.1 Levels of Oil-Soluble Furofuran Lignans in Seed of Five Sesamum Species Level (mean ± standard deviation, mg/kg oil) Species S. indicum

S. alatum* S. angustifolium* S. latifolium** S. schinzianum

Sesamin

Sesamolin

Reference

7,000 ± 1,800 5,260 ± 2,090 6,970 ± 4,110 5,500 ± 1,700 3,630 ± 3,110 100 ± 00 3,200 ± 400 24,000 ± 1,000 2,560 5,460

4,100 ± 800 3,040 ± 1,220 5,370 ± 2,310 5,000 ± 800 2,270 ± 1,280 100 ± 00 1,600 ± 100 200 ± 00 350 1,080

Beroza and Kinman 1955 (n = 33) Fukuda et al. 1988 (n = 14) Hemalatha and Ghafoorunissa 2004 (n = 21) Kamal-Eldin and Appelqvist 1994 (n = 7) Moazzami and Kamal-Eldin 2006 (n = 65) Kamal-Eldin and Appelqvist 1994 (n = 3) Kamal-Eldin and Appelqvist 1994 (n = 3) Kamal-Eldin and Appelqvist 1994 (n = 3) Fukuda et al. 1988 (n = 1) Fukuda et al. 1988 (n = 1)

Other lignans; 13,700 ± 2,100 of 2-epi-sesalatin in S. alatum, and 31,500 ± 2,300 of sesangolin in S. angustifolium. ** In the original papers, S. latifolium was mistakenly named S. radiatum *

Chemical Studies on the Lignans and Other Minor Constituents of Sesame Seed Oil

83

in sesamolin content of the white Japanese sesame seeds (CV = 73%) were much greater compared to the variations in sesamin contents (CV = 38%) as well as to sesamolin content in the brown and black seeds (CV = 27–33%). Tashiro et al. (1990) identified two types of white sesame seeds according to sesamolin content and identified an “A type” having a sesamolin content in a range similar to that found in brown and black seeds and a “B type” having a significantly lower sesamolin content. In our previous study on sesame seeds from Sudan (Kamal-Eldin and Appelqvist 1994b), one accession of black and one sample of brown sesame seeds showed a higher sesamolin (0.54% and 0.66%) and a lower sesamin (0.45% and 0.46%) compared to 5 white-seeded samples that contained 0.39–0.51% sesamolin and 0.23–0.72% sesamin. In this study, the variation was greater for sesamin (CV = 33.5%) than for sesamolin (CV = 18.1%), in agreement with Beroza and Kinman (1955). The sample size in these studies is indeed too small to draw a final consensus on the natural variation in sesamin and sesamolin contents in a world collection of sesame seeds. Sesamol, which is present in trace amounts in crude sesame oil, can be set free from sesamolin during acid clay bleaching (Fukuda et al. 1986a), hydrogenation (Budowski et al. 1950), and frying (Fukuda et al. 1986b). Acid clay bleaching, a process that occurs during refining, is also responsible for molecular transformations, including epimerization of sesamin to episesamin and diasesamin as well as molecular rearrangement of sesamolin to sesaminol followed by epimerization of the latter to 2- and 6-episesaminols and diasesaminol (Fukuda et al. 1986c). These transformations appear in Figure 3.4, and their extent depends on the bleaching conditions. Thus, the lignan composition of refined sesame oils is very different from that of the original seed oils. Approximate quantification of total lignans in sesame oil is determined with the absorbance of a solution of the oil in isooctane or other solvent at ca. 235 nm. This method is good for fast screening of a large number of samples or in the case of limited availability of seed material, such as the O

O

O

O

OH O

O H

H

H

O

O

Sesamin

O

O

O

O

O H

H

O

H

O

H+

OH

O

O

O

Sesamol

O

H

H

Sesaminol O

O

6-Episesaminol

H+

H+ O

O O H

H O

Diasesamin O

H

H+

OH

O

O O H

H

OH

O

O O

2-Episesaminol

O

H+

O

O

OH

O

O

Episesamin

H

O

O

O

O

O

H+

O

O H

O

O

Sesamolin

H+ O

H+

H

O

O

Diasesaminol

O

O

Figure 3.4  Chemical transformations of sesamin and sesamolin by acid-clay bleaching during refining of sesame oil.

84

Sesame: The Genus Sesamum

Sesamin Sesamolin γ-Tocopherol

0

5

10 15 Retention Time (min)

20

25

Figure 3.5  A typical normal-phase high performance liquid chromatographic (HPLC) analysis of crude sesame oil using a fluorescence detector (excitation 296 nm and emission 324 nm).

collection of seeds from wild species. Sesame oil lignans are easily analyzed by normal-phase and reversed-phase HPLC and by gas chromatography of the unsaponifiable fraction (Kamal-Eldin et al. 1994). Analysis of lignans by normal-phase HPLC (Figure 3.5) is simple, as an oil solution is injected directly into the column, whereas analysis by reversed-phase HPLC often requires removal of the acyl lipids, such as by solid-phase extraction. Detection of chromatographically separated peaks can be performed by UV (290 nm) or fluorescence (Ex. 296 nm and Em. 324 nm). While much more sensitivity is obtained by the former detector, the use of a fluorescence detector allows co-determination of γ-tocopherol (vide infra).

Sterols Plant sterols, or phytosterols, are related structurally to cholesterol. In vegetable oils, they occur in three classes: desmethyl-, monomethyl-, and dimethyl sterols, which are present in free form or esterified to fatty acids (Kamal-Eldin et al. 1992; Kamal-Eldin and Appelqvist 1994b). Quantitatively, the sterols come next to lignans as components of the unsaponifiable fraction in sesame oils. The desmethyl sterols represent about 85–93% of the total sterols in Sesamum indicum, S. alatum, and S. angustifolium but only about 75% in S. latifolium, which is characterized by a higher percentage of monomethyl sterols (Kamal-Eldin and Appelqvist 1994b). About 65–80% of total sterols exist in free form and 20–35% in esterified forms. Although desmethyl sterols are present in both free and esterified forms, monomethyl- and dimethyl- sterols are present mainly in esterified forms. The relative fatty acid composition of the sterol ester fraction, as compared to that of total fatty acids, is composed mainly of saturated palmitic (24% and 10%) and stearic (12% and 7%) at the expense of oleic (36% and 44%) and linoleic (22% and 37%), respectively (Kamal-Eldin and Appelqvist 1994b). The major sterols in samples of S. indicum and three wild species from Sudan are seen in Table 3.2. The main desmethyl sterols in S. indicum are campesterol (12–17%), stigmasterol (6–9%), sitosterol (57–62%), and δ5-avenasterol (8–11%). Comparable proportions have been found in S. latifolium, but S. alatum contains higher proportions of campesterol (ca. 20%) and δ5-avenasterol (ca. 23%) at the expense of sitosterol (ca. 35%), and S. angustifolium has a slightly higher proportion of δ5-avenasterol (ca. 20%) and a slightly lower proportion of sitosterol (ca. 55%) (Kamal-Eldin and Appelqvist 1994b). The major monomethyl sterols are obtusifoliol, gramisterol, cycloeucalenterol, and citrostadienol, while the major dimethyl sterols are α-amyrin, β-amyrin, cycloartanol, and 24-methylene cycloartanol. As with desmethyl sterols, S. alatum is different from all other species regarding methylated sterol composition. The sterol composition of seed oil from S. indicum is comparable to previous reports (Itoh et al. 1973a, 1973b; Johansson and Croon 1981).

Chemical Studies on the Lignans and Other Minor Constituents of Sesame Seed Oil

85

Table 3.2 The Major Sterols and Their Levels and Proportions in Seed Oils of Cultivated and Wild Sesame Species from Sudan Unsaponifiable (% in oil) Total sterols (% in oil)

S. indicum

S. alatum

1.4–1.8 0.6–0.7

4.8 1.0

Relative Proportions of Sterol Fractions (%) Desmethyl sterols 87 90 Monomethyl sterols 10 5 Dimethyl sterols 3 5

S. latifolium* 2.6 0.5

75 20 5

S. angustifolium 3.6 0.6

90 8 2

Composition of the Sterol Fractions Major Desmethyl Sterols (relative %) Campesterol 15.2 Stigmasterol 6.8 Sitosterol 60.3 10.4 Δ5-Avenasterol

19.6 14.1 34.5 23.0

11.8 5.0 59.9 12.5

10.5 6.1 56.0 19.5

Major Monomethyl Sterols (relative %) Obtusifoiol 23.0 Gramisterol 21.6 Cycloeucalenol 7.9 Citrostadienol 24.5

34.7 26.1 3.2 15.5

19.4 11.7 10.9 47.4

13.6 13.3 8.4 44.5

Major Dimethyl Sterols (relative %) 6.4 α-Amyrin 6.1 β-Amyrin Cycloartenol 44.2 24-Methylenecycloartanol 30.7

3.1 13.0 22.9 27.1

4.0 4.1 51.0 32.9

4.8 5.6 44.1 27.6

*

In the original papers, S. latifolium was mistakenly named S. radiatum.

Tocopherols Sesame oil contains 440–550 mg/kg total tocopherols, of which 95.5–99% are γ-tocopherol, 1–3.1% δ-tocopherol, and 95%), small percentages of diacylglycerols and monoacylglycerols, approximately 1% lignans (mainly sesamin and sesamolin), and trace amounts of sterols (Namiki 1995; Peng and Tzen 1998). The phospholipids found in sesame oil bodies are 41.2% phosphatidylcholine, 15.8% phosphatidylethanolamine, 20.9% phosphatidylinositol, and 22.1% phosphatidylserine (Tzen et al. 1993). Details about sesame-oil-body proteins, namely abundant structural proteins, oleosins of 15-17 kDa, and several minor proteins of higher molecular masses (Chen et al. 1998), follow.

189

Seed Oil Bodies of Sesame and Their Surface Proteins

Sterol B

PL

Sterol A

TAG

Ca

kDa Steroleosin B Steroleosin A

41 39

Caleosin A

27

Caleosin B Oleosin H1

17

Oleosin H2 Oleosin L

Oleosin

6-stranded β-barrel

2 nm Proline knob TAG matrix

Caleosin Proline knob

2 nm

15.5 15

Steroleosin TAG matrix

Proline knob

2 nm

TAG matrix PL

PL PL Cytosol Cytosol

Cytosol Parallel β-barrel

?? ?? ??

Figure 10.2  Structural models of a sesame oil body and three oil-body proteins. Isoforms of oleosin, caleosin, and steroleosin are resolved in a SDS-PAGE gel with their molecular masses indicated on the right. (From Lin, L.J. and J.T.C. Tzen. 2004. Plant Physiology and Biochemistry 42:601–608. With permission.)

Structure of Sesame Oil Bodies Three essential constituents of sesame oil bodies are organized in a unique manner: the abundant oil molecules are assembled in a matrix that is surrounded by a monolayer of phospholipids embedded with proteins (Figure 10.2). The assembly of oil matrix is the result mainly of the hydrophobic interaction of the oil molecules. The monolayer phospholipids are aligned in a half-unit membrane with their acyl moieties facing the oil matrix and head groups exposed to the cytosol. Proteins covering nearly the entire surface of the sesame oil bodies sustain their integrity and stability by providing steric hindrance and electronegative repulsion between these oil storage organelles (Tzen et al. 1997). Therefore, the compressed oil bodies in cells of mature sesame seeds never coalesce or aggregate, even after long-term storage. Purified sesame oil bodies maintain their structural integrity and stability at their physiological conditions of pH 7.5 (Figure  10.3A). Aggregation of sesame oil bodies occurs by an attenuation of electrostatic repulsion, such as by lowering pH of the medium from 7.5 to 6.5 (Figure 10.3B). The aggregated sesame oil bodies do not coalesce, presumably because of the steric hindrance of surface proteins. Trypsin digestion, which destroys surface proteins and eliminates steric hindrance, induces coalescence of sesame oil bodies (Figure 10.3C).

190

Sesame: The Genus Sesamum

A

Sesame Oil Bodies, pH 7.5 B

Sesame Oil Bodies, pH 6.5 C

Sesame Oil Bodies + Trypsin

Figure 10.3  Light microscopy of purified sesame oil bodies after different treatments (Tzen et al. 1997). Sesame oil bodies were suspended in a potassium phosphate buffer pH 7.5 (A) or pH 6.5 (B) and left at 23°C for 6 h. Preparation (A) was digested with trypsin at 23°C for 30 min before taking photos (C). All three photos are of the same magnification. Bar represents 5 µm. (From Tzen, J.T.C. et al. 1997. Journal of Biochemistry (Tokyo) 121:762–768. With permission.)

Three Classes of Proteins in Sesame Oil Bodies To date, three classes of oil-body-associated proteins—oleosin, caleosin, and steroleosin—have been identified in sesame seeds (Figure 10.2), with isoforms present in each of these classes (Chen et al. 1997, 1999; Frandsen et al. 2001; Lin et al. 2002; Lin and Tzen 2004; Tai et al. 2002). Oleosin, the most abundant protein class found in sesame oil bodies, presumably serves as the structural factor that maintains the integrity and stability of these oil storage organelles (Tzen et al. 2003a). Caleosin possesses a calcium-binding motif and several potential phosphorylation sites that may regulate some biological functions related to the synthesis or degradation of oil bodies (Chen and

Seed Oil Bodies of Sesame and Their Surface Proteins

191

Tzen 2001). Steroleosin comprises a sterol-binding dehydrogenase that belongs to a super-family of pre-signal proteins involved in signal transduction after binding to its regulatory sterol (Lin et al. 2002). These three classes of oil-body proteins found in sesame are present in seed oil bodies of diverse species (Lin et al. 2005). Characterization of oil bodies and associated proteins in sesame seed may further an understanding of properties of oil bodies and their proteins in other seed species. Because of the insolubility of sesame-oil-body proteins presumably caused by their hydrophobic oil-body anchoring domains, no three-dimensional structure derived from X-ray or NMR is yet available for oleosin, caleosin, or steroleosin. We predict the secondary structures of the three oil-body proteins based on their sequence analyses.

Proposed Structure of Sesame Oleosin A sesame oleosin molecule comprises three structural domains: an N-terminal amphipathic domain, a central hydrophobic oil-body anchoring domain, and a C-terminal amphipathic α-helical domain (Figure 10.2). The N-terminus of sesame oleosin is blocked with acetylation after the removal of the first methionine, a co-translational modification presumably related to its structural stability against ubiquitinated degradation for fulfilling the biological function of long-term protection of the organelles (Lin et al. 2005). Both N- and C-terminal domains of sesame oleosins reside on the oil body surface and stabilize the organelles via steric hindrance and electronegative repulsion (Tzen et al. 1997). The central hydrophobic anchoring domain of the sesame oleosin is highly homologous to that of oleosins from other plant species, particularly in a relatively hydrophilic proline knot motif at the middle of the sequence. This conservative oil-body anchoring domain comprises approximately 70 amino acid residues, representing the longest hydrophobic segment ever found in natural proteins (Tzen et al. 1992). The central hydrophobic domain of sesame oleosin is proposed to comprise paired β-strands and loop regions that form a six-stranded antiparallel β-barrel (Tzen et al. 2003b).

Sesame Oleosin Isoforms All known oleosins can be classified as one of the two isoforms, H- or L- (high or low molecular weight) oleosins (Tzen et al. 1990), and both coexist at the surface of each oil body (Tzen et al. 1998). The main difference between these two isoforms is an insertion of 18 residues in the C-terminal domain of H-oleosins, accounting for a 2 kDa difference in mass found in many species (Tai et al. 2002). While both classes of oleosin are present in seed oil bodies of diverse angiosperms (with one or more isoforms in each oleosin class of the same species), only L-oleosin occurs in gymnosperms. These findings imply that L-oleosin is the more primitive class, with H-oleosin derived from L-oleosin before the divergence of monocot and dicot species during evolution (Wu et al. 1999). Three oleosin isoforms of 17, 15.5, and 15 kDa are present in sesame oil bodies (Figure 10.2), two H-oleosins and one L-oleosin (Figure 10.4). The physiological significance of the presence of two oleosin isoforms remains to be elucidated.

Proposed Structure of Sesame Caleosin Similar to oleosin, sesame caleosin comprises three structural domains: an N-terminal hydrophilic calcium-binding domain, a central hydrophobic oil-body anchoring domain, and a C-terminal hydrophilic phosphorylation domain (Figure 10.2). The N-terminus of sesame caleosin is also blocked with acetylation after the removal of the first methionine, presumably resulting from the same cotranslational modification found in sesame oleosin (Lin et al. 2005). The N-terminal hydrophilic domain consists of a helix-turn-helix calcium-binding (EF hand) motif of 28 residues including an invariable glycine residue as a structural turning point and five conserved oxygen-containing residues as calcium-binding ligands (Chen et al. 1999). The calcium-binding capacity of caleosin is in accord with the calcium staining of oil bodies under electron microscopy, as reported before the

192

Sesame H1 Sesame H2 Arab. H1 Arab. H2 Arab. H3 Maize H1 Maize H2 Rice H Sesame L Arab. L1 Arab. L2 Arab. L3 Maize L Rice L Pine L

H-form insertion

N-terminal Domain

113 101 127 125 110 122 115 109 98 126 116 100 113 105 87

Central Domain

Proline knot

Sesame H1 Sesame H2 Arab. H1 Arab. H2 Arab. H3 Maize H1 Maize H2 Rice H Sesame L Arab. L1 Arab. L2 Arab. L3 Maize L Rice L Pine L

42 30 56 54 39 51 44 38 27 55 45 29 42 34 16

166 144 199 191 183 187 175 172 145 174 173 141 156 148 140

C-terminal Domain

Sesame H1 Sesame H2 Arab. H1 Arab. H2 Arab. H3 Maize H1 Maize H2 Rice H Sesame L Arab. L1 Arab. L2 Arab. L3 Maize L Rice L Pine L

Sesame: The Genus Sesamum

Figure 10.4  Sequence alignment of oleosin isoforms (Tai et al. 2002). Sequences are aligned according to the three structural domains (N-terminal, central hydrophobic, and C-terminal domains) of oleosins. The location of a putative insert of an 18-residue fragment in the C-terminal domain of H-oleosins is boxed. The four invariable residues in the proline knot motif are enclosed. The accession numbers of the aligned sequences are AF302807, U97700, and AF091840 for sesame H1, H2, and L; S71180, Z54164, AAF01542, AAC42242, S22538, and Z54165 for Arabidopsis (Arab.) H1, H2, H3, L1, L2, and L3; P21641, S52030, and S52029 for maize H1, H2, and L; U 43931 and U43930 for rice H and L. (From Tai, S.S. et al. 2002. Bioscience, Biotechnology, and Biochemistry 66:2146–2153. With permission.)

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discovery of caleosin on the surface of these oil storage organelles (Busch et al. 1993). The central hydrophobic domain comprises an amphipathic α-helix and an anchoring region. The amphipathic α-helix is located in the interface between hydrophobic and hydrophilic environments. The short anchoring region comprises a pair of anti-parallel β-strands connected with a proline knot-like motif. Several phosphorylation sites conservative in all available caleosin sequences occur in the C-terminal hydrophilic domain.

Sesame Caleosin Isoforms Two caleosin isoforms of similar molecular mass (27 kDa) are present in sesame oil bodies (Figure  10.2). In contrast to oleosin isoforms that are unique to oil bodies, caleosin isoforms or caleosin-like proteins are possibly present in other cellular locations, such as endoplasmatic reticulum (Næsted et al. 2000). Moreover, an invariable cysteine residue that is not involved in any intra- or inter-disulfide linkage occurs near the C-termini of caleosin isoform-B in diverse species (Figure 10.5). This conservative cysteine residue is predicted as a potential site for palmitoylation that may be related to the trafficking and assembly of caleosin-B into membrane structure.

Proposed Structure of Sesame Steroleosin Structurally different from oleosin and caleosin, sesame steroleosin comprises an N-terminal oilbody anchoring domain and a soluble sterol-binding dehydrogenase domain (Figure 10.2). The free N-terminus occurs in sesame steroleosin with the translation-initiating methionine determined as the first residue, in contrast to the acetylation-blocked N-termini of oleosin and caleosin (Lin et al. 2005). The N-terminal anchoring segment comprises two amphipathic α-helices (12 residues in each helix) connected by a hydrophobic sequence of 14 residues bordered by 1-2 proline at each end (Lin et al. 2002). The relatively hydrophilic proline residues located in both ends of the 14-residue hydrophobic sequence appear to aggregate in hydrophobic surroundings and form a unique structure, termed the proline knob motif, for the integrity and stability of steroleosin anchorage on the surface of oil bodies. The soluble sterol-binding dehydrogenase domain contains an NADPH-binding subdomain, an active site region, and a sterol-binding sub-domain. The NADPH-binding region, active site, and sterol-binding region are putatively located in the C-terminal ends of a parallel β-sheet. The NADPH-binding region is presumably located in the crevice region, termed the topological switch point, as observed in all similar α/β structures (Brandeen 1980).

Sesame Steroleosin Isoforms Two steroleosin isoforms of 41 and 39 kDa are present in sesame oil bodies (Figure 10.2). Similar to caleosin isoforms, steroleosin isoforms or steroleosin-like proteins are possibly present in other cellular locations besides oil bodies (Lin and Tzen 2004). Homologous proteins of steroleosin are present probably in all kinds of living organisms, including bacteria and humans; they mostly lack the N-terminal hydrophobic anchoring domain, and possess a highly conservative NADPH-binding sub-domain and active site, but a diverse sterol-binding sub-domain (Lin et al. 2002). The apparent distinction of the two steroleosin isoforms in sesame oil bodies, namely having diverse sterol-binding sub-domains (Figure 10.6), implies that they may be regulated by different sterols to conduct two distinct biological functions related to the formation or degradation of seed-oil bodies.

Functions of Oleosin The structural role of oleosin is to prevent, via electronegative repulsion and steric hindrance, coalescence of oil bodies during seed desiccation and to maintain them as discrete and relatively small organelles for long-term storage (Tzen et al. 1992). In contrast, oil drops in the mesocarp of

194 Sesame Cal-A Sesame Cal-B Arab Cal-A Arab Cal-B Barley Cal-A Barley Cal-B Rice Cal-A Rice Cal-B

6 5 3 52 3 5 2 5

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Ca2+ EF-hands binding domain 99 98 96 95 156 100 98 98

α-helix

Proline knot

136 135 133 132 193 137 135 135 192 191 189 188 249 193 191 191

Sesame Cal-A Sesame Cal-B Arab Cal-A Arab Cal-B Barley Cal-A Barley Cal-B Rice Cal-A Rice Cal-B

Sesame Cal-A Sesame Cal-B Arab Cal-A Arab Cal-B Barley Cal-A Barley Cal-B Rice Cal-A Rice Cal-B

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Sesame Cal-A Sesame Cal-B Arab Cal-A Arab Cal-B Barley Cal-A Barley Cal-B Rice Cal-A Rice Cal-B

*

245 244 245 243 301 246 243 244

C-terminal Domain

Sesame Cal-A Sesame Cal-B Arab Cal-A Arab Cal-B Barley Cal-A Barley Cal-B Rice Cal-A Rice Cal-B

Figure 10.5  Sequence alignment of caleosin isoforms. Sequences are aligned according to the three structural domains (N-terminal, central hydrophobic, and C-terminal domains) of caleosins. The positions of a calcium-binding motif, an amphipathic α-helix, and a proline knot-like motif are indicated on top of the sequences. A conserved cysteine residue present in isoform-B is indicated by a star. The accession numbers of the aligned sequences are: AAF13743, AAY87906, NP_194404, NP_200335, AAQ74238, AAQ74240, XP_473140, and XP_473143 for sesame, Arabidopsis (Arab), barley, and rice isoforms A and B.

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Arab STO-B Arab STO-A

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Arab STO-B

362 389 348 349

Figure 10.6  Sequence alignment of steroleosin isoforms (Lin and Tzen 2004). Sequences are aligned according to four proposed structural regions (oil-body anchoring segment, NADP+ binding subdomain, dehydrogenase activity site, and sterol binding subdomain). Predicted secondary structures are indicated on top of the sequences; the locations of α-helices and β-strands are indicated and labeled successively. The accession numbers of the aligned sequences are: AF302806, AF498264, BAA96983, and CAB39626 for sesame and Arabidopsis (Arab) isoforms A and B. (From Lin, L.J. and J.T.C. Tzen. 2004. Plant Physiology and Biochemistry 42:601–608. With permission.)

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olive and avocado containing no oleosin play no role in long-term lipid storage (Ross et al. 1993). In addition to its structural role, Vance and Huang (1987) speculate that oleosin serves as the target site for lipase after germination.

Proposed Functions of Caleosin and Steroleosin While no physiological functions have been characterized for either caleosin or steroleosin isoforms, it is reasonable to hypothesize that these oil-body proteins play certain biological roles during oil-body synthesis or degradation, such as signaling for oil-body formation, assembly, fusion, or mobilization and serving as a receptor for lipase attachment or glyoxysome docking. Caleosin comprises a calcium-binding motif and several potential phosphorylation sites, which are well-known candidates involved in signal transduction (Chen et al. 1999). Steroleosin possesses a sterol-binding dehydrogenase that belongs to a super-family of pre-signal proteins involved in signal transduction via activation of its partner receptor after binding to a regulatory sterol (Lin et al. 2002). Since caleosin and steroleosin are of similar abundance in sesame oil bodies, it will be interesting to see whether caleosin is regulated by a partner pre-signal molecule, presumably the sterol-activated steroleosin, and whether it serves as a receptor or signaling molecule on the surface of oil bodies during seed maturation or germination.

Gene Families of Sesame Oil-Body Proteins So far, cDNA sequences encoding three oleosin isoforms, two caleosin isoforms, and two steroleosin isoforms have been cloned from maturing sesame seeds (accession numbers: AF302807, U97700, and AF091840 for oleosins; AF109921 and DQ088381 for caleosins; AF302806 and AF498264 for steroleosins). In a database search of 3328 EST sequences from maturing sesame seeds (Suh et al. 2003), EST sequences derived from cDNA fragments encoding abundant oleosin-H1 and oleosin-L isoforms are identified. However, no EST sequences derived from cDNA fragments encoding the minor oleosin-H2, caleosin isoforms, and steroleosin isoforms occur in these sesame EST sequences, presumably owing to their low expression levels during seed maturation. Apparently, a random sequencing of three thousand EST clones is insufficient for functional genomics analysis of minor proteins in sesame oil bodies.

Genomic Organization and Expression of Sesame Oil-Body Proteins Introns appear in caleosin and steroleosin genes but not in most known oleosin genes from diverse species (Huang 1992; Murphy 2001; Tzen et al. 2003b). Genes encoding oleosin, caleosin, and steroleosin isoforms are present mostly in single copy in plant genome. All mRNAs coding for sesame oleosin, caleosin, and steroleosin isoforms, specifically, accumulate in maturing seeds when oil bodies are actively assembled, and disappear in mature seeds (Chen et al. 1999; Lin and Tzen 2004; Tai et al. 2002). No mRNA coding for any sesame oil-body protein appears in germinating seeds and seedlings.

Targeting and Assembly of Sesame Oil Body Proteins We have investigated the targeting of oleosin, caleosin, and steroleosin to sesame oil bodies using an in vitro system by constituting artificial oil emulsions to mimic maturing seed oil bodies for integration of translated proteins (Tzen et al. 2003a). The results suggest that steroleosin and caleosin/oleosin may be assembled into maturing oil bodies at different locations of endoplasmic reticulum (ER) membrane: caleosin/oleosin are directly targeted to maturing oil bodies where ER membranes are enlarged with deposited TAG molecules, whereas steroleosin is directed by an

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Ribosome mRNA Cytosol

SRP receptor

Nascent steroleosin SRP

Steroleosin

Steroleosin

Oleosin

Oleosin Rough ER

Oil body TAG

(Budding) Caleosin

Smooth ER

Caleosin

Figure 10.7  Targeting model of oleosin, caleosin, and steroleosin to a maturing sesame oil body.

N-terminal hydrophobic domain and integrated into the PL bilayer of ER membrane via a signal recognition particle (SRP)-dependent pathway prior to its lateral migration to maturing oil bodies (Figure 10.7). The distinct targeting routes of steroleosin and caleosin/oleosin are in agreement with the following two observations. First, steroleosin and caleosin/oleosin target and anchor to oil bodies via different structural organizations. Steroleosin possesses a non-cleavable N-terminal signal sequence putatively responsible for ER targeting via an SRP-dependent pathway, and the anchoring to oil bodies lies mainly in this N-terminal hydrophobic domain; caleosin and oleosin, lacking an N-terminal signal sequence, target/anchor to oil bodies via their central hydrophobic domains. Second, steroleosin possesses a free methionine at its N-terminus while caleosin and oleosin are N-terminally blocked by acetylation, after the removal of the first methionine residue (Lin et al. 2005). Presumably, the N-terminus of steroleosin is protected by an SRP complex and/or embedded in ER membrane during its synthesis and targeting, while the N-termini of caleosin and oleosin are freely exposed to cytocol during their synthesis and targeting to maturing oil bodies via central hydrophobic domains.

Reconstitution of Artificial Sesame Oil Bodies With the same proportions of the three essential constituents (matrix oil, phospholipid, and protein) in native sesame oil bodies, we successfully constituted artificial sesame oil bodies of similar sizes (0.5–2 μm) and stability by sonication (Tai et al. 2002). We could also control sizes of these artificial oil bodies by changing the ratio of matrix oil over oil-body protein, and a normal distribution with an average size proportional to this ratio was displayed (Peng et al. 2003). Both thermo- and structural stability of artificial sesame oil bodies decreased as their size increased, and vice versa. With surface proteins cross-linked by glutaraldehyde or genipin, the maximum temperature that these artificial oil bodies could tolerate was elevated from 50° to 90°C. The reconstituted sesame oil bodies were stabilized by the combination of oleosin isoforms or any oleosin isoform alone, i.e., oleosin-H1, oleosin-H2, or oleosin-L; a slightly better structural stability was observed in artificial oil bodies constituted with oleosin-L than in those constituted with either of the two H-oleosin isoforms (Tai et al. 2002). The stabilizing effect of recombinant oleosin expressed in Escherichia

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coli for these reconstituted oil bodies was comparable to that of native oleosin isolated from sesame seeds (Peng et al. 2004a).

Reconstitution of Smaller Artificial Oil Bodies with Caleosin Stable artificial oil bodies 10 times smaller (50–200 nm) than native sesame oil bodies were successfully constituted with matrix oil, phospholipid, and sesame caleosin (Chen et al. 2004). These small artificial oil bodies stabilized by sesame caleosin possessed higher thermostability (up to 70°C) and were maintained as discrete particles at lower pH surroundings in comparison with those stabilized by sesame oleosin. Artificial oil bodies stabilized by recombinant sesame caleosin expressed in E. coli were comparable in size, topology, and stability to those encapsulated with native sesame caleosin. In contrast, artificial oil emulsions were unstable when sesame caleosin was replaced by an equivalent quantity of sesame steroleosin, in absence of oleosin, under the same reconstitution condition.

Artificial Sesame Oil Bodies as a Protein Expression/Purification System We have developed a bacterial expression/purification system for producing recombinant proteins by using artificial oil bodies constituted with sesame oil, phospholipid, and recombinant sesame oleosin-fused polypeptide (Peng et al. 2004a). In this system, a target protein was first over-expressed as an insoluble oleosin-fused polypeptide, collected from the pellet of cell lysate simply by centrifugation, assembled into artificial sesame oil bodies, and released via a specific proteolytic cleavage, and then harvested by concentrating the ultimate supernatant. This technique offers a powerful and competitive alternative to affinity chromatography conventionally used for protein purification. However, the requirement of a relatively expensive endopeptidase, e.g., factor Xa or thrombin, for specific release of the target protein from its recombinant oleosin-fused polypeptide raises the processing cost substantially, and thus restricts its potential applications (Peng et al. 2004b). Recently, we further improved this bacterial expression/purification system as exemplified by the production of nattokinase in E. coli (Chiang et al. 2005). This revised system involved basically the same procedures as described above, except that the target enzyme was released from the artificial sesame oil bodies via self-splicing of the intein (a self-splicing polypeptide induced by chemical supplement or temperature alteration) linker. Compared to the previous system using an expensive protease for specific cleavage, the release of target protein via intein self-splicing induced by temperature alteration or dithiothreitol supplement reduces the processing cost significantly.

Artificial Sesame Oil Bodies as a Matrix for Enzyme Immobilization We have also developed a new technique of enzyme fixation designed to achieve, in one step, protein refolding and immobilization by linking a target enzyme, e.g., D-hydantoinase, to sesame oleosin on the surface of artificial oil bodies (Chiang et al. 2006). The conversion yield of the immobilized D-hydantoinase, an industrial enzyme, exceeded 80% after 7 cycles of repeated use. Moreover, this immobilized enzyme remained stable for at least 15 days when stored at 4°C. Apparently, the simple and effective system of fixing target proteins on the surface of artificial sesame oil bodies is practical and useful in immobilizing enzymes with low solubility.

Artificial Oil Bodies as a Carrier for Drug Delivery In contrast, smaller artificial oil bodies constituted with sesame oil, phospholipid, and sesame caleosin have been used to develop an oral delivery system for hydrophobic drugs—cyclosporine

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A, for example, a drug commonly utilized as a clinical immunosuppressant to prevent transplant rejection and to treat several autoimmune diseases (Chen et al. 2005). An oral-delivery formulation with cyclosporine A efficiently encapsulated in caleosin-stabilized artificial oil bodies that stayed extremely stable for weeks at 4°C exhibited better bioavailability in an animal test than the commercial formulation Sandimmun Neoral®. Whether this drug delivery system is applicable to intravenous injection remains to be evaluated.

Concluding Remarks In the past decade, we investigated the structure and organization of sesame oil bodies and their associated proteins intensively. Oleosin, caleosin, and steroleosin, the three classes of proteins identified in sesame oil body, have served as model systems for studying the function of pertinent proteins on the surface of these lipid storage organelles that occur universally in oily seeds. Gene families encoding isoforms of these three oil-body proteins have been sequenced from maturing sesame seeds. Oleosin- and caleosin-stabilized artificial oil bodies have been successfully reconstituted and used to develop various systems for biotechnological applications. Further investigation and technical improvement will create novel artificial oil bodies as versatile vehicles to fulfill many other requirements for specialized applications.

References Brandeen, C.I. 1980. Relation between structure and function of alpha/beta-proteins. Quarterly Reviews of Biophysics 13: 317–338. Busch, M.B., K.H. Kortje, H. Rahmann and A. Sievers. 1993. Characteristic and differential calcium signals from cell structures of the root cap detected by energy-filtering electron microscopy (EELS/ESI). European Journal of Cell Biology 60: 88–100. Chen, E.C., S.S. Tai, C.C. Peng and J.T.C. Tzen. 1998. Identification of three novel unique proteins in seed oil bodies of sesame. Plant and Cell Physiology 39: 935–941. Chen, J.C., R.H. Lin, H.C. Huang and J.T.C. Tzen. 1997. Cloning, expression and isoform classification of a minor oleosin in sesame oil bodies. Journal of Biochemistry (Tokyo) 122: 819–824. Chen, J.C., C.C. Tsai and J.T.C. Tzen. 1999. Cloning and secondary structure analysis of caleosin, a unique calcium-binding protein in oil bodies of plant seeds. Plant and Cell Physiology 40: 1079–1086. Chen, J.C. and J.T.C. Tzen. 2001. An in vitro system to examine the effective phospholipids and structural domain for protein targeting to seed oil bodies. Plant and Cell Physiology 42: 1245–1252. Chen, M.C., C.L. Chyan, T.T. Lee, S.H. Huang and J.T.C. Tzen. 2004. Constitution of stable artificial oil bodies with triacylglycerol, phospholipid, and caleosin. Journal of Agricultural and Food Chemistry 52: 3982–3987. Chen, M.C., J.L. Wang and J.T.C.Tzen. 2005. Elevating bioavailability of cyclosporine a via encapsulation in artificial oil bodies stabilized by caleosin. Biotechnology Progress 21: 1297–1301. Chiang, C.J., H.C. Chen, Y.P. Chao and J.T.C. Tzen. 2005. Efficient system of artificial oil bodies for functional expression and purification of recombinant nattokinase in Escherichia coli. Journal of Agricultural and Food Chemistry 53: 4799–4804. Chiang, C.J., H.C. Chen, Y.P. Chao and J.T.C. Tzen. 2006. A simple and effective method to prepare immobilized enzymes using artificial oil bodies. Enzyme and Microbial Technology 9: 1152–1158. Frandsen, G.I., J. Mundy and J.T.C. Tzen. 2001. Oil bodies and their associated proteins, oleosin and caleosin. Physiologia Plantarum 112: 301–307. Huang, A.H.C. 1992. Oil bodies and oleosins in seeds. Annual Review of Plant Physiology 43: 177–200. Lin, L.J., S. S. Tai, C.C. Peng and J.T.C. Tzen. 2002. Steroleosin, a sterol-binding dehydrogenase in seed oil bodies. Plant Physiology 128: 1200–1211. Lin, L.J. and J.T.C. Tzen. 2004. Two distinct steroleosins are present in seed oil bodies. Plant Physiology and Biochemistry 42: 601–608. Lin, L.J., P.C. Liao, H.H. Yang and J.T.C. Tzen. 2005. Determination and analyses of the N-termini of oil-body proteins, steroleosin, caleosin and oleosin. Plant Physiology and Biochemistry 43: 770–776. Murphy, D.J. 2001. The biogenesis and functions of lipid bodies in animals, plants and microorganisms. Progress in Lipid Research 40: 325–438.

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Næsted, H., G.I. Frandsen, G.Y. Jauh, I. Hernandez-Pinzon, H.B. Nielsen, D.J. Murphy, J.C. Rogers and J. Mundy. 2000. Caleosins: Ca2+-binding proteins associated with lipid bodies. Plant Molecular Biology 44: 463–476. Namiki, M. 1995. The chemistry and physiological functions of sesame. Food Research International 11: 281–329. Peng, C.C. and J.T.C. Tzen. 1998. Analyses of the three essential constituents of oil bodies in developing sesame seeds. Plant and Cell Physiology 39: 35–42. Peng, C.C., I.P. Lin, C.K. Lin and J.T.C. Tzen. 2003. Size and stability of reconstituted sesame oil bodies. Biotechnology Progress 19: 1623–1626. Peng, C.C., J. C.F. Chen, D.J.H. Shyu, M.J. Chen and J.T.C. Tzen. 2004a. A system for purification of recombinant proteins in Escherichia coli via artificial oil bodies constituted with their oleosin-fused polypeptides. Journal of Biotechnology 111: 51–57. Peng, C.C., D.J.H. Shyu, W.M. Chou, M.J. Chen and J.T.C. Tzen. 2004b. Method for bacterial expression and purification of sesame cystatin via artificial oil bodies. Journal of Agricultural and Food Chemistry 52: 3115–3119. Ross, J.H.E., J. Sanchez, F. Millan and D.J. Murphy. 1993. Differential presence of oleosins in oleogenic seed and mesocarp tissues in olive (Olea europaea) and avocado (Persea americana). Plant Science 93: 203–210. Suh, M.C., M.J. Kim, C.G. Hur, J.M. Bae, Y.I. Park, C.H. Chung, C.W. Kang and J.B. Ohlrogge. 2003. Comparative analysis of expressed sequence tags from Sesamum indicum and Arabidopsis thaliana developing seeds. Plant Molecular Biology 52: 1107–1123. Tai, S.S., M.C. Chen, C.C. Peng and J.T.C. Tzen. 2002. Gene family of oleosin isoforms and their structural stabilization in sesame seed oil bodies. Bioscience, Biotechnology, and Biochemistry 66: 2146–2153. Tzen, J.T.C.,Y.K. Lai, K.L. Chan and A.H. Huang. 1990. Oleosin isoforms of high and low molecular weights are present in the oil bodies of diverse seed species. Plant Physiology 94: 1282–1289. Tzen, J.T.C., G.C. Lie and A.H. Huang. 1992. Characterization of the charged components and their topology on the surface of plant seed oil bodies. Journal of Biological Chemistry 267: 15626–15634. Tzen, J.T.C.,Y. Cao, P. Laurent, C. Ratnayake and A. Huang. 1993. Lipids, proteins, and structure of seed oil bodies from diverse species. Plant Physiology 101: 267–276. Tzen, J.T.C., C.C. Peng, D.J. Cheng, E.C. Chen and J.M. Chiu. 1997. A new method for seed oil body purification and examination of oil body integrity following germination. Journal of Biochemistry (Tokyo) 121: 762–768. Tzen, J.T.C., R.L. Chuang, J.C. Chen and L.S. Wu. 1998. Coexistence of both oleosin isoforms on the surface of seed oil bodies and their individual stabilization to the organelles. Journal of Biochemistry (Tokyo) 123: 318–323. Tzen, J.T.C., M.M.C. Wang, J.C.F. Chen, L.J. Lin and M.C.M. Chen. 2003a. Seed oil body proteins: oleosin, caleosin, and steroleosin. Current Topics in Biochemistry Research 5: 133–139. Tzen, J.T.C., M.M.C. Wang, S.S.K. Tai, T.T.T. Lee and C.C. Peng. 2003b. The abundant proteins in sesame seed: storage proteins in protein bodies and oleosins in oil bodies. Advances in Plant Physiology 6: 93–105. Vance, V.B. and A.H. Huang. 1987. The major protein from lipid bodies of maize. Characterization and structure based on cDNA cloning. Journal of Biological Chemistry 262: 11275–11279. Wu, L.S.H., G.H.H. Hong, R.F. Hou and J.T.C. Tzen. 1999. Classification of the single oleosin isoform and characterization of seed oil bodies in gymnosperms. Plant and Cell Physiology 40: 326–334.

of Near-Infrared 11 Use Reflectance Spectroscopy for Nondestructive Analyses of Sesame Tetsuo Sato, Aye Aye Maw, and Masumi Katsuta Contents Introduction..................................................................................................................................... 201 Materials and Methods.................................................................................................................... 201 Chemical Measurements.................................................................................................................202 Near Infrared Spectroscopy Methodology......................................................................................202 Results and Discussion...................................................................................................................202 Plural Seed Analysis.......................................................................................................................203 Single Seed Analysis.......................................................................................................................204 Relationship between NIR Spectral Patterns and FA Composition................................................205 References....................................................................................................................................... 210

Introduction The genetic improvement of sesame (Sesamum indicum L.) constituents and their fatty acid (FA) composition are central research subjects (Mosjidis 1984; Tashiro 1989). However, the determination of these constituents by conventional methods is tedious and time-consuming. We need a simple and rapid analytical method for screening sesame varieties and lines. Since the cultivars and lines are very precious in a breeding project, a nondestructive analytical method is desirable so that we can plant the samples after analyses. Near infrared (NIR) spectroscopy is a useful tool in agriculture and nutritional analyses (Barton and Kays 2001; Norris 1987; Osborne and Fearn 1993; Shenk et al. 2001). We have reviewed the feasibility of NIR spectroscopy for the nondestructive estimation of the major constituents and the FA composition in sesame seeds. We describe here single seed analysis and the relationship between NIR spectral patterns and FA composition (Sato et al. 2003, 2004, 2006).

Materials and Methods Thirty sesame samples were collected in Myanmar by the Seed Bank Project of the Japan International Cooperation Agency (Tokyo). Additionally, 52 samples of Japanese varieties and breeder’s lines were received from the National Institute of Crop Science (Tsukuba) in 1997–2001, and were sent to the National Agricultural Research Center for the Kyushu Okinawa Region (Kumamoto) for these analyses (Sato et al. 2003, 2004, 2006). Our tests used samples from 23 yellowish-brown, 15 darkbrown, 18 black, and 26 white seed coats.

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Chemical Measurements Moisture content, oil content, and total nitrogen (N) content were determined using a vacuum oven drying method, the Soxhlet method, and the Dumas method, respectively. The protein content was converted to expression on a moisture-free basis by multiplying the total N percentage obtained by the protein factor: 5.30 (Japanese Society for Food Science and Technology 1996). We also used the extracted oils for gas chromatographic (GC) analysis after methyl-esterification (Sato et al. 2003, 2004, 2006).

Near Infrared Spectroscopy Methodology We used a Bran and Luebbe (B+L) InfraAlyzer 500 (Norderstedt, Germany) to measure the NIR reflectance spectra in the wavelength range between 1100 and 2500 nm at 2-nm intervals. We packed intact sesame seeds tightly into the cavity of a single-grain cup (center hole diameter = 24 mm, (B+L)). We covered the cup with a glass lid to level the sample surface. We placed an intact single sesame seed into the cavity of a modified single-grain cup (center hole diameter = 20 mm (B+L)) (Sato et al. 1998, 2003), which enabled us to obtain clear NIR spectra by optimizing the collection of the reflected light from a small sample. We measured the NIR reflectance spectrum of an individual seed without a glass lid. We divided the samples into two sets: a calibration set composed of 55 samples and a prediction set composed of 27 samples. We carried out multiple linear-regression analysis on the NIR averaged spectral data with the chemical data using the InfraAlyzer data analysis system (IDAS) software (B+L). We calculated the first- and second-derivative NIR spectra using the default parameters. We used glass slides and a syrup cup (Sato et al. 1998, 2003) to measure the NIR transflectance spectra of the extracted oil.

Results and Discussion Figure 11.1 shows the original NIR spectra of a sesame cultivar with a yellowish-brown seed coat (‘Masekin’) and a cultivar with a black seed coat (‘Iwateguro’). The overall spectra for sesame with yellowish-brown, dark-brown, and white seed coats were similar. In contrast, those with black seeds show a different spectrum. These variable NIR spectra typically showed different patterns at 1100 1.2 1

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Figure 11.1  Original NIR spectra of plural seeds and a single seed of sesame (‘Masekin’: yellowishbrown coat; ‘Iwateguro’: black coat). (From Sato, T. et al. 2006. Plant Production Science 9:161–164. With permission.)

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203

to 1400 nm (Figure 11.1). We carried out multiple linear-regression analyses combining these two NIR spectra.

Plural Seed Analysis Table 11.1 describes the results of the calibration process for plural seeds. According to Osborne and Fearn (1993), moisture has an absorption band around 1940 nm, oil has absorption bands at 1700–1800 nm, 2100–2200 nm, and 2300–2400 nm, and protein has absorption bands at 1980 nm, 2050 nm, and 2180 nm. The absorption at 1710 nm provides information about the degree of unsaturation. The selected wavelengths were reflections of the chemical structures of the constituents, and were influenced by them, or were used to correct or reverse correlations: wavelengths of 1867 nm, 2019 nm, and 2411 nm for the absorption band of moisture, 1828 nm for that of oil, and 1966 nm and 2122 nm for that of protein. Figure 11.2 shows the regressions of the values estimated by the NIR method with those determined chemically. For the major constituents, the NIR method works well. For FA composition, the NIR method works well for oleic and linoleic acids, but poorly for palmitic and stearic acids, because the variation of the palmitic acid proportion was too narrow to calculate and did not allow us to select the proper calibration equations. The standard error of calibration for stearic acid was almost as great as the standard deviation of the stearic acid proportions for the prediction sample set. Overall, the results indicate that we can apply NIR spectroscopy successfully as a simple, rapid, and nondestructive screening method for the selection of sesame seeds in the breeding programs, regardless of sesame seed coat color. Katsuta et al. (2006) used the same instrumentation and these calibrations to examine 650 sesame accessions from the National Institute of Agrobiological Science Genebank (Tsukuba). They Table 11.1 Calibration Results Developed for Plural Seeds Based on Plural Seeds Data Calibration

Moisture

Oil Protein Palmitic acid proportion Stearic acid proportion Oleic acid proportion

Linoleic acid proportion

Wavelengths Used

r

SEC

6.663 + 49.262 × d1L(1427) + 587.702 × d1L(1555) − 875.456 × d1L(1583) − 263.708 × d1L(1867) + 114.664 × d1L(2019) − 352.631 × d1L(2091) + 233.480 × d1L(2411) 39.391 − 397.525 × L(1200) + 399.210 × L(1216) + 145.163 × L(1400) − 318.613 × L(1516) + 186.207 × L(1828) 23.672 − 852.020 × d2L(1590) − 338.677 × d2L(1746) + 316.458 × d2L(1966) + 721.942 × d2L(2122) 7.604 + 40.506 × L(1436) − 45.916 × L(1476) + 132.248 × L(1912) − 140.292 × L(1924) + 19.780 × L (1952) 6.618 − 67.482 × d2L(1358) − 37.980 × d2L(1410) + 139.014 × d2L(1686) − 814.339 × d2L(1810) − 85.129 × d2L(2166) + 96.323 × d2L(2322) 40.927 + 438.761 × d1L(1479) − 3391.399 × d1L(1719) − 2461.745 × d1L(1747) + 2412.552 × d1L(1755) + 633.051 × d1L(1879) + 1061.221 × d1L(2003) − 469.015 × d1L(2279) 42.372 − 1957.603 × d1L(1707) + 3783.052 × d1L(1715) − 2951.203 × d1L(1847) − 2705.246 × d1L(2059) + 2266.029 × d1L(2067)

0.979

0.236

0.931

1.248

0.939

0.618

0.593

0.509

0.869

0.305

0.898

1.105

0.942

0.917

Source: Sato, T. et al. 2004. Plant Production Science 7:363–366. With permission. Note: r: Correlation coefficient between chemical method and NIR method; SEC: Standard error of calibration; L(1200): Raw spectral data at 1200 nm; d1L(1427): First derivative spectral data at 1427 nm; and d2L(1358): Second derivative spectral data at 1358 nm.

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7

Palmitic acid proportion r = 0.699 SEP = 0.616

11 10

6

9

5.5

8

5 mcSEP = 0.580 bias = 0.236

7 6

6

7

8

9

10

11

12

NTR Method (%)

39

8 NTR Method (%)

7

5

45

30 30

35

6

26 24 22

5.5 mcSEP = 0.324 bias = –0.010

4.5 4

3

4 5 6 7 8 Vacuum Drying Method (%)

6.5

7

45

50

Protein r = 0.916 SEP = 0.830 mcSEP = 0.836 bias = 0.125

20

40 35 9 35

6

40

Oil r = 0.913 50 SEP = 1.431 mcSEP = 1.395 bias = –0.416 45

6.5

5

5.5

55

Moisture r = 0.958 SEP = 0.318

7.5

4.5

35

mcSEP = 1.063 bias = 0.126 39 41 43 GC Method (%)

4

Linoleic acid proportion r = 0.959 45 SEP = 0.826 mcSEP = 0.799 bias = 0.259 40

41

37

4

50

Oleic acid proportion r = 0.889 43 SEP = 1.051

35 35

mcSEP = 0.331 bias = –0.126

4.5

45

37

Stearic acid proportion r = 0.849 SEP = 0.348

6.5

18 40 45 50 Soxhlet Method (%)

55

18

20 22 24 Dumas Method (%)

26

Figure 11.2  Predicted results with the calibration equations developed for plural seeds on plural seeds. (Data from Sato, T. et al. 2004. Plant Production Science 7:363–366; and Sato, T. et al. 2003. Journal of the American Oil Chemists’ Society 80:1157–1161. With permission.)

confirmed our estimates by NIR analyses with chemical measurements of 50 representative samples, and obtained the correlation coefficient (r) of 0.866 for oil content, and r = 0.879 for protein content.

Single Seed Analysis When we adopted the calibration equations shown in Table 11.1 developed for plural seed analysis, we obtained the predicted results, as shown in Figure 11.3. These compare well with the spectral values of a single seed. Figure 11.3 shows that the regression lines were biased and skewed in this case. We were able to obtain rough estimates of all constituents aside from the palmitic and the stearic acid fractions, because those variation ranges were as small as the standard error of prediction (SEP). For that reason, we developed a single seed analysis. Table 11.2 describes the calibration process developed for a single seed analysis. The wavelengths selected for moisture were used for the correction or reverse correlation: 1694, 1786, and 2354 nm, the oil absorption bands. Those for oil were

205

Use of Near-Infrared Reflectance Spectroscopy for Nondestructive Analyses of Sesame 14

7

Palmitic acid proportion

13

6.5

12

6

11

5.5 r = 0.296 SEP = 3.396 mcSEP = 0.745 bias = 3.316

10 9

Measurements by NIR Method (%)

8

NIR Method (%)

9 8

Stearic acid proportion r = 0.724

6

7

8

9

5 4.5 10

11

12

44 Oleic acid proportion r = 0.719 SEP = 1.747 42

4

4 48

SEP = 0.523 mcSEP = 0.456 bias = 0.270 4.5

5

5.5

6

6.5

7

Linoleic acid proportion 46 r = 0.794 SEP = 1.913 44 42

40

40

38

38

mcSEP = 1.710 36 bias = 0.487

36 mcSEP = 1.859 bias = –0.577 34 34 36 38 40 42 44 46 48

Moisture

36 38 40 42 44 Measurements by GC Method (%) 52 Oil 50 48

7

46

6

44

28 26

Protein

24 22

r = 0.821 20 r = 0.863 SEP = 2.085 SEP = 4.620 18 mcSEP = 1.409 4 40 mcSEP = 2.371 bias = 1.560 bias = 3.992 16 3 38 3 4 5 6 7 8 9 36 38 40 42 44 46 48 50 16 18 20 22 24 26 Dumas Method (%) Vacuum Drying Method (%) Soxhlet Method (%) 5

r = 0.870 SEP = 1.093 mcSEP = 0.809 bias = 0.752

42

28

Figure 11.3  Predicted results with the calibration equations developed for plural seeds on a single seed. (From Sato, T. et al. 2006. Plant Production Science 9:161–164. With permission.)

used for the correction or reverse correlation: 1910 and 2014 nm are the moisture or protein absorption bands. Those for protein reflect the chemical structures of the constituents: 2130 nm; to correct or reverse the correlation: 1658, 1770, and 2442 nm for oil. Figure 11.4 shows the results estimated by this NIR method developed for single seed analysis, as described in Table  11.2. The bias and the skew are drastically improved. The SEPs are also improved. In each contribution, the square of the correlation coefficient was greater than 60% for all but the palmitic acid proportion. Therefore, we may estimate the constituents accurately with the exception of the palmitic acid portion.

Relationship between NIR Spectral Patterns and FA Composition An NIR analysis is viewed as a statistical method, specifically, a multiple linear-regression analysis. We took another approach in this section. NIR spectral patterns reflect FA composition because they are affected by unsaturation and the carbon chain lengths of the FA, especially in the 1600–1800 nm range (Sato 1994, 1995, 2002; Sato et al. 1990, 1991, 1995, 1998, 2002). However, we cannot

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Table 11.2 Calibration Results Developed for a Single Seed Based on Single Seed Data Calibration

Moisture Oil Protein Palmitic acid Stearic acid

Oleic acid Linoleic acid

Wavelengths Used

r

SEC

5.456 + 140.604 × d2L(1358) + 122.372 × d2L(1694) – 208.897 × d2L(1786) – 612.431 × d2L(2354) 47.936 + 2206.146 × d2L(1286) + 8077.092 × d2L(1582) – 1429.898 × d2L(1806) + 502.12 × d2L(1910) + 1057.239 × d2L(2014) 19.988 + 363.749 × d2L(1658) + 1310.065 × d2L(1770) + 1090.023 × d2L(2130) + 1246.508 × d2L(2442) – 0.581 + 1535.238 × L(1556) – 1811.068 × L(1568) + 291.426 × L(1640) 7.06 – 178.501 × L(1700) + 358.891 × L(1868) – 320.288 × L(1888) + 1363.675 × L(1996) – 1242.712 × L(2000) – 541.866 × L(2364) + 732.221 × L(2372) – 174.33 × L(2424) 12.85 + 4922.612 × L(1700) – 6833.522 × L(1704) – 7029.406 × L(1716) + 9182.861 × L(1720) – 195.613 × L(1944) 57.434—1994.11 × L(1700) + 10446.434 × L(1712)—8667.844 × L(1720) + 186.063 × L(2076)

0.922

0.489

0.924

1.302

0.892

0.810

0.492 0.885

0.540 0.294

0.847

1.306

0.866

1.349

Source: Data from Sato, T. et al. 2006. Plant Production Science 9:161–164; and Sato, T. et al. 2003. Journal of the American Oil Chemists’ Society 80:1157–1161. With permission. Note: r: Correlation coefficient between chemical method and NIR method; SEC: Standard error of calibration; L(1200): Raw spectral data at 1200 nm; d1L(1427): First derivative spectral data at 1427 nm; and d2L(1358): Second derivative spectral data at 1358 nm.

detect spectral differences related to FA composition in the original NIR spectra. Furthermore, we cannot detect any differences in the second-derivative NIR spectra, which we calculated using the default parameters. Therefore, in order to examine the relationship between NIR spectral patterns and FA composition, we adopted the following parameters for calculating the second-derivative spectra: the size of the moving average was 4 nm, the size of the derivative segments was 12 nm, and the gap between the derivative segments was 12 nm. To compare the spectra easily and to obtain a wider difference, we standardized these NIR spectra, setting the spectral value of 1600 nm to 0.0 and that for 1724 nm to –1.0. Figure 11.5a reveals that as the percentage of linoleic acid increases in sesame oil, the absorption band around 1708 nm moves sharply downward in the second-derivative NIR spectra, because the spectral phase is reversed in the second-derivative spectra. Figure 11.5b shows the plural seeds study, whose pattern is similar to the single seed test. Typically, when the absorption band near 1660 nm is solidly downward in the second-derivative spectra, the band near 1708 nm is also sharply downward, as shown by the solid line. However, in the case of some samples with black seed coats, we observe a different pattern. The dotted line in Figure 11.5b shows that the absorption band near 1660 nm is shifted to the longer wavelength region, and that it moves sharply downward in the second-derivative spectra. However, the band near 1708 nm moves just weakly downward, different from the case shown by a solid line. In tests of the extracted oil, there are no exceptions, even in the oil from seeds with black coats. The narrow range of the FA composition in sesame accounts for the spectral differences smaller than those noted with other oilseeds (Sato et al. 1991, 1995, 1998, 2002). In the case of intact seeds, the spectral differences are greater, owing to the heterogeneity of the samples, whereas in the case of extracted oil, the samples are more homogeneous. Based on these observations, we selected the standardized reading at 1708 nm for the prediction of the linoleic acid portion of total FA composition. Figure 11.6 shows the correlation between

Use of Near-Infrared Reflectance Spectroscopy for Nondestructive Analyses of Sesame 12 11 10

8

5 mcSEP = 0.732 bias = 0.266

Measurements by NIR Method (%)

6

44 42

7

8

9

10

11

4.5 12

Oleic acid proportion r = 0.836 SEP = 1.270

4

bias = –0.129 4

4.5

5

5.5

6

6.5

7

48

Linoleic acid proportion 46 r = 0.853 SEP = 1.455 44 42

40

40

38

38 mcSEP = 1.266 bias = –0.263

36

36 38 40 42 44 Measurements by GC Method (%)

9 NIR Method (%)

6 5.5

6

Stearic acid proportion r = 0.789 SEP = 0.391 mcSEP = 0.376

6.5

9

7

Moisture 8 r = 0.931 SEP = 0.415 7 mcSEP = 0.420 bias = 0.049 6 5

52

Oil 48 r = 0.906 SEP = 1.486 46 44 42 40

4 3

7

Palmitic acid proportion r = 0.348 SEP = 0.766

207

36

mcSEP = 1.482 bias = 0.039

34 34 36 38 40 42 44 46

48

28 Protein 26 r = 0.885 SEP = 0.972 24 mcSEP = 0.972 bias = 0.190 22 20

18 mcSEP = 1.441 bias = –0.455 16 36 16 36 38 40 42 44 46 48 50 Soxhlet Method (%) 38

3

4 5 6 7 8 9 Vacuum Drying Method (%)

18 20 22 24 26 Dumas Method (%)

28

Figure 11.4  Predicted results with the calibration equations developed for a single seed on a single seed. (From Sato, T. et al. 2006. Plant Production Science 9:161–164. With permission.)

the linoleic acid portion and the standardized reading at 1708 nm. The scatter plots show that the more sharply downward the band at 1708 nm is, the higher the linoleic acid portion of total FA. The shaded triangles were derived from the spectra represented by the dotted curve in Figure 11.5b and were excluded as outliers in the calculation of the correlation coefficients. In the case of oil samples, there were no outliers (Figure 11.6a). The correlation coefficient was –0.925 for extracted oil (Figure 11.6a), –0.786 for sesame seeds (Figure 11.6b), and –0.830 in the case of a single sesame seed (Figure 11.6c). The second-derivative NIR reading at 1708 nm provides an index of the ratio of linoleic acid to total FA composition. These results show that a rough estimation of the percentage of linoleic acid (C18:2) is possible using this method. On the other hand, the oleic acid (C18:1) fraction of total FA composition shows an inverse association to the standardized readings at 1708 nm. We obtain a rough estimation of the linoleic acid portion of total FA composition in sesame seeds using a single sesame seed, except for cultivars with a black coat.

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Sesame: The Genus Sesamum

C18:1 33.78 44.12

1

C18:2 47.70% 38.05

0.5 0 –0.5 –1 1600

1650

1700

1750

1800

(a) Extracted Sesame Oil C18:1 36.93 44.15

Corrected-d2log (1/R)

1

C18:2 43.08% 35.96

0.5 0 –0.5 –1 1600

1650

1700 1750 Wavelength (nm)

1800

(b) Sesame Seeds

Figure 11.5  Standardized second-derivative NIR spectra in the 1600–1800 nm region using modified parameters. (From Sato, T. et al. 2003. Journal of the American Oil Chemists’ Society 80:1157–1161. With permission.)

Use of Near-Infrared Reflectance Spectroscopy for Nondestructive Analyses of Sesame –0.46

209

r = –0.9250

–0.48 –0.5 –0.52 –0.54 –0.56 –0.58 –0.6 38

40

42

44

46

48

(a) Extracted Seasame Oil Ones from normal spectral patterns Ones from different spectral patterns –0.7 –0.75 –0.8 –0.85 –0.9 –0.95 –1 34

36

38

40

42

44

46

48

38 40 42 44 Linoleic Acid Ratio (%)

46

48

(b) Sesame Seeds

Corrected-d2log(1/R) at 1708 nm

–0.75 –0.8 –0.85 –0.9 –0.95 –1 –1.05 34

36

(c) A Single Sesame Seed

Figure 11.6  Correlation between the linoleic acid proportion of the total FA composition and the standardized NIR spectral readings at 1708 nm: a) extracted sesame oil, b) sesame seeds, and c) a single sesame seed. (From Sato, T. et al. 2003. Journal of the American Oil Chemists’ Society 80:1157–1161. With permission.)

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Sesame: The Genus Sesamum

This method does not require empirical calibration equations. We can adopt this nondestructive method to screen cultivars by FA content and other useful properties related to FA composition.

References Barton, F.E. and S.E.E. Kays. 2001. Analytical application to fibrous foods and commodities. In P. Williams and K.H. Norris, eds., Near-Infrared Technology in the Agricultural and Food Industries. 215–231. American Association of Cereal Chemists, St. Paul, Minnesota. Japanese Society for Food Science and Technology. 1996. New Food Analysis Methods. 30. Kohrin Publishing Co., Tokyo. Katsuta, M., S. Yasumoto and T. Sato. 2006. Evaluation of the seed constituents of sesame germplasm accessions revealed by the simplified analysis methods. Proceedings of 10th International Congress of the Society for the Advancement of Breeding Research in Asia and Oceania (SABRAO). Poster C-20. SABRAO conference proceedings were issued in CD-ROM format. Mosjidis, J.A. and D.M. Yermanos. 1984. Maternal effects and cytoplasmic inheritance of oleic and linoleic acid contents in sesame. Euphytica 33: 427–432. Norris, K.H. 1987. Near–infrared reflectance spectroscopy: The present and future. In Y. Pomeranz, ed., Cereal ‘78: Better Nutrition for the World’s Millions. 245–251. American Association of Cereal Chemists, St. Paul, Minnesota. Osborne, B.G. and T. Fearn. 1993. Applications of near-infrared spectroscopy in food analysis. In B.G. Osborne, T. Fearn and P.H. Hindle eds., Near-Infrared Spectroscopy in Food Analysis: Longman Science and Technical. 2nd ed. 145–191. John Wiley & Sons, New York. Sato, T. 1994. Application of principal-component analysis on near infrared spectroscopic data of vegetable oils for their classification. Journal of the American Oil Chemists’ Society 71: 293–298. Sato, T. 1995. Sesame oil is very low in linoleic acid: A reply. Journal of the American Oil Chemists’ Society 72: 1089. Sato, T. 2002. New estimation method for fatty acid composition in oil using near infrared spectroscopy. Bioscience, Biotechnology, and Biochemistry 66: 2453–2458. Sato, T., S. Kawano and M. Iwamoto. 1990. Detection of foreign fat adulteration of milk fat by near infrared spectroscopic method. Journal of Dairy Science 73: 3408–3413. Sato, T., S. Kawano and M. Iwamoto. 1991. Near infrared spectral patterns of fatty acid analysis from fats and oils. Journal of the American Oil Chemists’ Society 68: 827–833. Sato, T., Y. Takahata, T. Noda, T. Yanagisawa, T. Morishita and S. Sakai. 1995. Nondestructive determination of fatty acid composition of husked sunflower (Helianthus annua L.) seeds by near infrared spectroscopy. Journal of the American Oil Chemists’ Society 72: 1177–1183. Sato, T., I. Uezono, T. Morishita and T. Tetsuka. 1998. Nondestructive estimation of fatty acid composition in seeds of Brassica napus L. by near infrared spectroscopy. Journal of the American Oil Chemists’ Society 75: 1877–1881. Sato, T., M. Takahashi and R. Matsunaga. 2002. Use of NIR spectroscopy for estimation of FA composition of soy flour. Journal of the American Oil Chemists’ Society 79: 535–537. Sato, T., A.A. Maw and M. Katsuta. 2003. NIR reflectance spectroscopic analysis of FA composition in sesame (Sesamum indicum L.) seeds. Journal of the American Oil Chemists’ Society 80: 1157–1161. Sato, T., A.A. Maw and M. Katsuta. 2004. Nondestructive near-infrared reflectance spectroscopic analyses of the major constituents in sesame (Sesamum indicum L.) whole seeds with different coat color. Plant Production Science 7: 363–366. Sato, T., A.A. Maw and M. Katsuta. 2006. Nondestructive near-infrared reflectance spectroscopy of sesame (Sesamum indicum L.) components by single seed analysis. Plant Production Science 9: 161–164. Shenk, J.S., J.J. Workman and M.O. Westerhaus. 2001. Application of NIR spectroscopy to agricultural products. In D. A. Burns and E. W. Ciurczak, eds., Handbook of Near-Infrared Analysis. 419–474. Marcel Dekker, NY. Tashiro, T. 1989. Goma no hinshu to seibunkagaku. In M. Namiki and T. Kobayashi, eds., Goma no Kagaku. 59–65. Asakurashoten, Tokyo.

Protective Role in 12 Sesame’s Crop Nematode Control Gamal Abdalla Elbadri and Abdelmageed Mohammad Yassin Contents Introduction..................................................................................................................................... 211 Associations between Sesame and Nematodes............................................................................... 211 Current Methods Used for Controlling Plant Parasitic Nematodes................................................ 213 Value of Sesame in Crop Rotation.................................................................................................. 214 Commercial Nematicides Derived from Sesame............................................................................ 215 Neo-Tec® S.O............................................................................................................................. 215 Dragonfire-CPP™ 100% Organic Nematicide.......................................................................... 215 Barmac Neotrol.......................................................................................................................... 215 Nemagard (Natural Organic Products International)................................................................. 215 Conclusion...................................................................................................................................... 216 Acknowledgment............................................................................................................................ 216 References....................................................................................................................................... 216

Introduction Nematodes are multicelluar, nonsegmented, true roundworms that can be pathogenic to specific agricultural crops. Scant investigation has been undertaken associating plant parasitic nematodes with sesame. We observe in Sudan, a major world producer, that sesame (Sesamum indicum L.) is nematode resistant, at least to Meloidogyne incognita, M. javanica, and Pratylenchus spp., and worldwide some root-knot nematodes attack some sesame varieties with only a few nematode galls (Starr and Black 1995; Varma et al. 1978; Walker et al. 1998). Sesame suppresses plant parasitic nematodes, and we suggest it is of enormous value in designing a rotation with a susceptible crop.

Associations between Sesame and Nematodes Plants with nematicidal properties can effectively reduce soil populations of nematodes and improve yields when grown with susceptible crops or as a cover crop (Bridge 1987). Despite the wide host ranges of the root-knot nematode Meloidogyne javanica Kofoid and White 1919, it can sometimes be controlled by a suitable cover crop or with crop rotation. Crops that include sesame, Crotalaria juncea L., Dolichas lablab L., or Elymus glaucus Buckl. reduce root-knot nematode numbers in the soil (Araya and Caswell-Chen 1994a; 1994b). Cover crops, both annual and biennial, also manage nematodes. However, little information is available about their effects on M. javanica and the mode of action by which they reduce Meloidogyne spp. Sesame has been successful in management of Meloidogyne arenaria, M. incognita, and M. javanica (McSorley et al. 1994, McSorley and Dickson 1995; Sipes and Arakaki 1997; Tanda and Atwal 1988).

211

212

Sesame: The Genus Sesamum

Environmental concerns, health hazards, and the high cost of nematicides have stimulated research on alternative nematode management practices for plant parasitic nematodes (Araya and Caswell-Chen 1994a; Ferris et al. 1992; McKerny 1987). In recent studies, the reproduction of Meloidogyne arenaria race 1, M. incognita races 1 and 3, and M. javanica on 10 cultivars of sesame was examined in greenhouse tests (Guerena 2006; Starr and Black 1995). Sesame was a poor host for M. incognita race 1 and race 3. No sesame genotype supported more than 70 eggs/root. Reproduction of M. arenaria race 1 on sesame varied from 20 eggs/g roots for cultivar ‘Sesaco 7CB’ to 1,570 egg/g roots for ‘Sesaco 10’ in the greenhouse (Starr and Black 1995). Limited reproduction of M. incognita and M. arenaria occurred on four sesame cultivars (Rodriguez-Kabana et al. 1988). Sesame appears to be a suitable rotational crop for management of populations of M. arenaria and M. incognita on peanut and cotton, respectively (Starr and Black 1995). Green manure plants such as Sudan grass, ‘Sordan 79’ (Sudan grass x sorghum cv ‘Sordan 79’), Sorghum sudanense variety ‘Trudan 8,’ sesame, and velvet bean (Mucuna deeringiana (Bort) Merr.) reduced soil populations of M. hapla in strawberry plantings, below fallow levels (Northeastern Regional Association of State Agricultural Experiment Stations 1999). In Pakistan, five oil cake amendments, linseed, sesame, cotton, caster, and mustard (13 g/pot), with wheat straw and sawdust (8 g/pot) with NPK, controlled root-knot nematodes (Gul and Shah 1990; Gul and Zulfiqar 1990; Zulfiqar and Gul 1990). All of the amendments depressed the nematode populations compared to the control, resulting in only a few galls per plant. A suppressive soil is defined as one that could have a nematode problem but does not. It is thought that one or more biological organisms in the soil suppress nematode populations. Trying to document that a soil is suppressive is no easy task. Growing a nematode-suppressive crop will not eliminate plant parasitic nematodes from the soil. However, it may reduce nematode numbers enough to allow production of nematode-susceptible plants in a nematode-infested field, bed, or garden. If nematode populations are high, cropping several successive suppressive or non-host crops will be required before a susceptible crop may be grown without the protection of a nematicide. Nematode populations can often rebound to pretreatment levels on a susceptible vegetable or field crop grown after the production of a nematode-suppressive crop. Nevertheless, suppression of nematodes with nematode-suppressive crops has been similar to or somewhat better than suppression of nematodes obtained with a weed-free summer fallow (Hagan et al. 1998). The addition of organic amendments to soil is a common feature of subsistence farming, mainly as a means of improving soil fertility and structure (Bridge 1987). Many organic soil amendments have been tested to control plant parasitic nematodes. Sesame is commonly used (Table 12.1). Nematode-infested fields have high rates of nematode infestation for several years. These levels then fall and remain at low levels. It is thought that some biological organisms in the soil are functioning to maintain nematode populations at a low level. For example, in the U.K., it has been reported that populations of Heterodera avenea that infested some cereal crops in the first five years after planting decreased thereafter through the action of Nematophothora gynophila and Verticillium chlamydosporium (Kerry 1987). Likewise, Dacytlella oviparsitica effectively controlled the population of Meloidogyne spp. on peaches in California (Stirling and Mankau 1978). Sesame has a deep taproot that produces a natural biocide that suppresses most nematodes, and growers have noted a suppression of nematode populations in rotation crops such as cotton and peanuts, and in other crops. However, note that observers’ views vary. Starr and Black (1995) documented the suppression of several genera of root-knot nematodes (Meloidogyne spp.) in soil where sesame grows, but Smith et al. (2000) report that most sesame varieties are not resistant to root-knot nematodes. Soil amendments tested for their ability to reduce problems from parasitic nematodes include waste products (e.g., coffee grinds) from manufacturing processes, crops grown specifically for this role (e.g., marigolds, vetch, and sesame), and microbial organisms (Table 12.2) or mixtures of microbials (e.g., Microplex, Microlife, and Farewell) selected and increased via fermentation.

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Sesame’s Protective Role in Crop Nematode Control

Table 12.1 Reaction of Nematode Suppressive Crops to Common Nematode Pests Common Root-knot Species Suppressive Crop French Marigold (Tagetes patula) ‘Tangerine’ ‘Happy Days’ ‘Lemondrop’ ‘French Dwarf Double’ Chrysanthemum (C. morifolium) ‘Escapade’ Castor Bean (Ricinus communis) ‘Bronze King’ ‘Hale’ Partridge Pea (Cassia fasciculata Michx.) Showy Crotalaria (C. spectabilis) Florida Velvetbean (Mucuna deeringiana) Common Vetch (Vicia sativa) ‘Cahaba White’ ‘Vantage,’ ‘Nova II,’ ‘Vanguard’ and ‘Warrior’ Rapeseed (Brassica napus) ‘Juniter,’ ‘Cascade,’ ‘Elena,’ ‘Indore,’ ‘Humas,’ ‘Bridger’ and ‘Dwarf Essex’ Sesame (Sesame indicum L.)

Southern

Peanut

Northern

Javanese

** — ** —

** — — —

** — — —

— ** — —

**

—

—

—

** — — ** **

— ** ** ** **

— — — — —

— — — ** **

** —

** **

— —

** —

**

—

—

**

—

**

—

—

Source: Hagan et al. 1998, Nematode Suppressive Crops. Auburn University, Alabama. Note: ** indicates a high level of suppression; — indicates no suppression or no available data.

Current Methods Used for Controlling Plant Parasitic Nematodes In practical terms, “control” of plant parasitic nematodes refers here to the suppression of the target species population density to an acceptable level, and “acceptable” refers to the economics of applying the control measure in relation to the financial return from the resultant increased yield (Weischer and Brown 2000). Nematicides must be toxic in order to poison the nematodes they are intended to control. However, they are environmentally unacceptable because they are potentially hazardous to humans and animals. An elegant form of control is through host plant resistance or tolerance. This is an area of research worthy of attention. The use of nematode-resistant crop cultivars appears to provide the most realistic method for the control of plant parasitic nematodes (Bridge 1987; Cook and Evans 1987). Cultivars resistant to plant parasitic nematodes are already widely used for specific crops in the United States, particularly in California and Florida. No fruit or vegetable nematode-resistant cultivar is resistant to all nematodes; however, many have resistance to the most common nematodes, often in combination with resistance to one or more other pathogens (EPA 2006). Many cowpea cultivars, such as ‘California Blackage #5,’ were found to be a poor host to Meloidogyne incognita (McSorley and Gallaher 1992), while other cowpea cultivars, such as ‘Elite,’ were found to be good hosts against M. incognita race 3 (Kirkpatrick and Morelock 1987). Many low-tech control measures can be applied to protect crop plants, such as phytosanitary measures, fallowing, flooding, using direct sunrays, and heating. Other species contain, or produce,

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Table 12.2 Organic Soil Amendments Tested for Nematode Control Oil Cakes Peanut Mustard Sesame Castor Maragosa (Neem) Mahuva Cotton seed Soybean Linseed Plant Crop Residues Grass hay Alfalfa (Lucerne) Oat straw Tree bark Green Manure Alfalfa Crotalaria Pineapple Cabbage leaves Margosa Neem (leaves) Apple leaves Pumpkin Water hyacinth Seaweed

Agroindusterial Wastes Tea waste (decaffeinated) Cotton waste Cassava flour waste Sugarcane bagasse Sugarcane molasses Rice husks Coffee husks Cocoa pods Cassava peelings Cellulose waste (paper-making) Sawdust Wood ash Mycelium waste Animal Waste Chicken manure Farmyard manure Fish gut Bone meal Crab chitin Urban Waste Sewage Refuse

Source: After Muller and Gooch 1982, Nematropica 12: 319–326.

substances toxic to phytonematodes, e.g., marigold (Tagetes spp.), castor bean (Ricinus communis L.), neem (Azadirachta indica A. Juss.), and Crotalaria spp. (Huang 1984). An inexpensive and effective method of phytonematode control is the incorporation into the soil of soil cakes infested with antagonistic organisms. Organisms with an antagonistic effect on phytonematodes are present in many groups, including bacteria, fungi, and nematodes. The fungi Paecilomyces lilacinus and Verticillium chlamydosporium and the bacterium Pasteuria penetrans gave successful results in controlling plant parasitic nematodes (Elbadri 1991; Jatala et al. 1980; Kerry 1987).

Value of Sesame in Crop Rotation Farmers in Alabama have added sesame into the rotation with cotton, peanut, and soybean (Guerena 2006). Nematodes levels are reduced and crop yields significantly increased in fields previously planted in sesame (Guerena 2006). Sesame is found to contain high levels of at least three compounds (aldehydes, ketones, and linolenic acids) toxic to nematodes yet nontoxic to animals and human (Castisano 2005; Poulenger 2002). When sesame stalks and roots are incorporated into the soil and activated with water, they slowly disintegrate, releasing the active compounds. Sesame has suppressive activity against the peanut root-knot nematode Meloidogyne spp. When grown as a summer annual, sesame proves to be equally or more effective than bahiagrass (Paspalum notatum Flugge) and cotton in reducing the carryover of peanut root-knot nematode

Sesame’s Protective Role in Crop Nematode Control

215

juveniles in the soil in a peanut or soybean production system. Sesame may be rotated with peanut, soybean, and possibly cotton. However, a single crop of sesame in a field heavily infested with the peanut root-knot nematode will not suppress nematode populations sufficiently to eliminate the need for a nematicide treatment on the following year’s peanut crop (Hagan et al. 1998).

Commercial Nematicides Derived from Sesame Numerous plant-based nematicides have been developed. They are currently being marketed for nematode management; some of these, such as sesame and mustard, are processed from dry plant material, and others are oil derived from plants such as sesame. A high amount of some nematicides from these products must be applied to control plant parasitic nematodes properly. However, it is also recommended that botanical pesticides must be used in conjunction with a biorational pest management program, and cannot be the primary method of pest control in the Farm Plan (Certified Organic Associations of British Columbia 2005). Some commercial nematicides that derive from sesame oil and sesame stalks are listed below.

Neo-Tec® S.O. Neo-Tec S.O. is a naturally derived nematicide for the control of plant parasitic nematodes on fine turfgrasses and ornamental crops. It is originally based on patented development work as a naturally derived control for plant parasitic nematodes. Neo-Tec S.O. and its granular partner Neo-Tec G.S.O. are derived from extracts of specific cultivars of hybrid sesame plants. The modes of action of Neo-Tec S.O. include allelochemics (with a nematoxic or nemastatic effect), anoxic rhizospheres, disruption of nematode to root, and disruption of male taxis to females (Parkway 2006).

Dragonfire-CPP™ 100% Organic Nematicide According to promotional information, Dragonfire-CPP is derived from sesame oil (100%) from an unspecific cultivar of “wild sesame.” Additional details about which line were not forthcoming, despite several requests for more information. It is suitable for fine turf, sports fields, and lawns at an application rate of 2.5–5 g per acre, depending on the nematode infestation in the area (Poulenger USA 2002). This product has not been registered by the EPA. Rather, Poulenger USA, Inc. represents this product as qualifying for exemption from registration under FIFRA 25(b).

Barmac Neotrol Neotrol is a product composed entirely of pelletized sesame plant stalks. It was imported into Australia originally as an oil conditioner and organic fertilizer and is currently sold for this purpose. Barmac Industries’ Material Data Safety Sheet (2003) indicates that the variety of sesame used to produce Neotrol has three naturally occurring chemicals that kill nematodes and make the product a viable and effective alternative to synthetic nematicides, thus overcoming a number of environmental and safety issues associated with using highly toxic synthetic nematicides. Neotrol may become a viable way of solving the current accelerated biodegradation problems occurring with Nemacur.

Nemagard (Natural Organic Products International) Nemagard, a nematicide made from ground sesame stalks, is used to control various plant nematode types such as root-knot, root-lesion, citrus, stubby-root, and dagger. This product is exempt from registration and reporting under Federal and California EPA standards (Guerena 2006; Peaceful Valley 2007). Nemagard may be used before planting annuals as well as on perennials, shrubs, and

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trees. For best results, apply before each growing season or crop; it works best as preventive maintenance. Incorporate below the soil surface and water thoroughly. Under optimum conditions, results will be observed within 5 weeks, and the effects will last the entire growing season. It is labeled for most crops, including vegetables, fruit trees, lawns, and ornamentals. Broadcast at 230 lb/acre, or 1/2 lb per 100 sq ft. Side dress Nemagard 4 to 6 inches on each side of a row and incorporate into the top 3 inches.

Conclusion The nematicidal effect of sesame in suppressing plant parasitic nematodes is of monumental value with a minimum of effort, as it is simply grown in rotation with susceptible crop species. This enterprise is becoming increasingly significant as ecological concerns demand reduction of the use of chemical pesticides and a replacement of them with botanical agents.

Acknowledgment The authors thank Dorothea Bedigian for substantial revision and bibliographic assistance for this chapter.

References Araya, M. and E.P. Caswell-Chen. 1994a. Penetration of Crotalaria juncea, Dolichas lablab, and Sesamum indicum roots by Meloidogyne javanica. Journal of Nematology 26: 238–240. Araya, M. and E.P. Caswell-Chen. 1994b. Host status of Crotalaria juncea, Sesamum indicum, Dolichas lablab and Elymus glaucus to Meloidogyne javanica. Journal of Nematology 26: 492–497. Barmac Industries. 2003. Material Safety Data Sheet. Box Flate Estate, Swanbank Rd., Swanbank Queensland 4306, Australia. www.barmac.com.au/pdf/msdsneot.pdf Bennett, M. 1996. Sesame Seed: A Handbook for Farmers and Investors, 361. Rural Industries Research and Development Corporation, Government of Australia. http://www.rirdc.gov.au/pub/handbook/sesame.pdf Bridge, J. 1987. Control strategies in subsistence agriculture. In R.H. Brown and B.R. Kerry, eds., Principles and Practice of Nematode Control in Crops. 389-420. Academic Press, New York. Castisano, A. 2005. Organic nematode management. Rural Connections 11(4). Hawaii Organic Farmers Association Hilo, HI. http://hawaiiorganicfarmers.org/newsletter12_05.htm#ORGANIC%20 NEMATODE%20MANAGEMENTBy:%20Amigo%20Cantisano Certified Organic Associations of British Columbia. 2005. Crop production materials list. Principles of organic farming. http://www.certifiedorganic.bc.ca/Standards/b2v7sec13.5.htm. Cook, R. and K. Evans. 1987. Resistance and Tolerance. In R.H. Brown and B.R. Kerry, eds., Principles and Practice of Nematode Control in Crops. 179–231. Academic Press, New York. Elbadri, G.A.A. 1991. Biological control of root-knot nematodes (Meloidogyne spp.) using nemtophagous fungi Paecilomyces lilacinus integrated with a nematicide. M.Sc. Thesis, Newcastle University, Newcastle upon Tyne, UK. EPA (Environmental Protection Agency). 2006. Using nematode resistant cultivars as an alternative to methyl bromide for selected crops. Ozone Depletion Rules and Regulations. http://www.epa.gov/Ozone/mbr/ casestudies/volume2/nema2.html. Ferris, H., C. Castro, E.P. Caswell, P.A Jaffee, P.A. Roberts, B.B. Westerdahl and V.M. Williamson. 1992. Biological approaches to the management of plant-parasitic nematodes. In M.L. Flint et al., eds., Beyond Pesticides: Biological Approaches to Pest Management in California. 68–101. University of California Division of Agricultural and Natural Resources. Publication 3354. Oakland, Cal. Guerena, M. 2006. Nematodes: Alternative Controls. National Sustainable Agriculture Information Service, Publication IP287. National Center for Appropriate Technology, USDA. http://attra.ncat.org/attra-pub/ nematode.html Gul, A.S. and S.F.A. Shah. 1990. Control of root-knot nematodes in tomato through organic amendments and NPK. Sarhad Journal of Agriculture 6: 95–97. Gul, A.S. and M. Zulfiqar. 1990. Promising control of root-knot nematodes (Meloidogyne) of tomato through organic amendments. Sarhad Journal of Agriculture 6: 417–420.

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Hagan, A., W. Gazaway and E. Sikora. 1998. Nematode Suppressive Crops. Auburn University, Auburn, Alabama. www.aces.edu/pubs/docs/A/ANR-0856/ANR-0856.pdf Huang, S.P. 1984. Cropping effects of marigolds, corn, and okra on population levels of Meloidogyne javanica and on carrot yields. Journal of Nematology 16: 396–398. Jatala, P., R. Kaltenback, M. Bocangel, A.J. Deraux and R. Campos. 1980. Field application of Paecilomyces lilacinus for controlling Meloidogyne incognita on potatoes. Journal of Nematology 12: 226–227. Kerry, B.R. 1987. Biological Control. In R.H. Brown and B.R. Kerry, eds., Principles and Practice of Nematode Control in Crops. 233–263. Academic Press, New York. Kirkpatrick, T.L. and T.E. Morelock. 1987. Response of cowpea breeding lines and cultivars to Meloidogyne incognita. Annals of Applied Nematology 1: 46–49. McKerny, M.V. 1987. Control strategies in high value crops. In R.H. Brown and B.R. Kerry, eds., Principles and Practice of Nematode Control in Crops. 329–349. Academic Press, New York. McSorley, R., D.W., Dickson, J.A., De Brito, T.E., Hewlett and J.J. Frederick. 1994. Effect of tropical rotation crops on Meloidogyne arenaria population densities and vegetable yields in micro plots. Journal of Nematology 26: 175–181. McSorley, R. and D.W. Dickson 1995. Effect of tropical crop rotation on Meloidogyne incognita and other plant parasitic nematodes. Journal of Nematology 27: 535–544. McSorley, R. and R.N. Gallaher. 1992. Comparison of nematode population densities on six summer crops at seven sites in North Florida. Supplement to the Journal of Nematology 24: 699–706. Muller, R. and P.S. Gooch. 1982. Organic amendments in nematode control. An examination of the literature. Nematropica 12: 319–326. Northeastern Regional Association of State Agricultural Experiment Station. 1999. Project NE-171: Biological and Cultural Management of Plant-Parasitic Nematodes. Annual Report. http://www.caes.state.ct.us/ CoopRegeionalResearchProject/NE-17/ProjectNE.htm Parkway Research. 2006. What’s New: NEO-TEC S.O. Naturally Derived Parasitic Nematode Control. Parkway Research, Springfield, Illinois. http:/www.parkwayresearch.com/whatsnew.html Peaceful Valley. 2007. Grow Organic Nemagard (50 lb). Peaceful Valley Farm and Garden Supply, Grass Valley, California. http://www.groworganic.com/item_PBT965_Nemagard_50_Lb.html?welcome=T Poulenger USA. 2002. DRAGONFIRE-CPP™ 100% Organic Nematicide. NaEx Corp-Poulenger USA. Stafford, Texas; Lakeland, Florida. http://www.poulengerusa.com/DragonfireCpp/dragonfirecpp.htm Rodriguez-Kabana, R., P.S. King, D.G. Roberts and C.F. Weaver. 1988. Potential of crops uncommon to Alabama for management of root-knot and soybean nematodes. Journal of Nematology 20: 116–120. Sipes, B.S. and A.S. Arakaki. 1997. Root-knot nematodes in dry land taro with tropical cover crops. Journal of Nematology 29: 721–724. Smith, D.T.W., J. Grichar and A.A. McCallum. 2000. Crop Profile for Sesame in United States. Crop Profiles. http://cipm.ncsu.edu/cropprofiles/docs/ussesame.html Starr, J.L. and M.G. Black. 1995. Reproduction of Meloidogyne arenaria, M. incognita, M. javanica on sesame. Journal of Nematology 27: 624–627. Stirling, G.R. and R. Mankau. 1978. Dactylella oviparasitica, a new fungal parasite of Meloidogyne eggs. Mycologia 70: 774–784. Tanda, A.S. and A.S. Atwal. 1988. Effects of sesame intercropping against root-knot nematode (Meloidogyne incognita) in okra. Nematologica 43: 484–492. Varma, M.K., H.C. Sharma and V.N. Pathak. 1978. Efficacy of Tagetes patula and Sesamum orientale against root-knot of egg plant. Plant Disease Reporter 62: 274–275. Walker, J.T., J.B. Melin and J. Davis. 1998. Response of Sesamum indicum and S. radiatum accessions to rootknot nematodes Meloidogyne incognita. Journal of Nematology 30: 611–615. Weischer, B. and D.J.F. Brown. 2000. An introduction to nematodes. In General Nematology. 159–175. Pensoft, Sofia, Moscow. Zulfiqar, M. and A.S. Gul. 1990. Organic amendments as control of root-knot nematodes. International Nematology Network 7: 22–24.

Biotechnology 13 Molecular of Sesame Mi Chung Suh, Nam-In Hyung, and Chung-Han Chung Contents Introduction..................................................................................................................................... 219 Molecular Strategy for Genetic Improvement of Lipid Composition in Sesame Oil..................... 220 Enhancing α-Linolenic Acid Content Using ω-3 Desaturase......................................................... 220 Enhancing γ-Linolenic Acid Content Using Δ-6 Desaturase..........................................................224 Molecular Strategy for Genetic Improvement of Tocochromanols in Sesame Seeds..................... 226 Enhancing α-Tocopherol Content in Sesame Using γ-Tocopherol Methyltransferase (γ-Tmt)..... 227 Enhancing Tocochromanol Content of Sesame Seeds.................................................................... 228 Molecular Strategy for Genetic Improvement of Sesame Storage Proteins................................... 229 Molecular Manipulation of Phytic Acid in Sesame: Role of Myoinositol 1-Phosphate Synthase.......................................................................................................................................... 229 Potential for Biotechnological Modification of Lignan Content in Sesame Seeds......................... 230 Development of Non-Shattering Sesame Varieties......................................................................... 231 Seed-Specific Promoters for Sesame Biotechnology...................................................................... 232 Potential for Molecular Pharming/Farming by Sesame Hairy Root Cultures................................ 232 Progress in Transgenic Technology of Sesame............................................................................... 233 Summary......................................................................................................................................... 236 References....................................................................................................................................... 237

Introduction Recent advances in plant biotechnology have revealed many novel and practical applications for genetic modification of various crop plants. Such applications include mediating resistance to various pathogens, herbicide resistance, tolerance to various stresses (drought, flooding, salt, frost, or high temperature), improved nutritional quality, high yield, longer storage life, optimized food processing, and molecular pharming/farming for therapeutic purposes (Slater et al. 2003). To improve oil quality, biotechnologists have reported genetically engineering oilseeds using molecular breeding technology, but such reports have focused largely on soybean, rapeseed, cottonseed, and sunflower seed (Chapman 2001; Damude and Kinney 2007, 2008; Drexler et al. 2003; Dyer and Mullen 2005, 2008; Murphy 2006; Napier et al. 2006; Napier 2007; Opsahl-Ferstad 2003; Scarth and Tang 2006; Stoll et al. 2005). In contrast, there is little information concerning biotechnological approaches to genetically improve sesame (Sesamum indicum L.) oilseeds. Despite the long cultivation history of the sesame seed (Bedigian 2000), its importance as a plant source for high quality vegetable oil (Chung et al. 1995), and its usefulness in Oriental folk medicine (Izawa 1980), sesame biotechnology has received little attention, presumably because of its geographically narrow use. Recently, studies have begun to accumulate more information about sesame biotechnology (Ali et al. 2007; Chun et al. 2003, 2007; Jin et al. 2001; Kim et al. 2006, 2007; Laurentin and Karlovsky 2006; Suh et al. 2003).

219

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Sesame: The Genus Sesamum

There are two primary biotechnological interests in sesame seeds, based on their two most significant functional constituents. One of these constituents is the oil; vegetable oils are an essential human nutrient implicated in a number of metabolic processes, such as biosynthesis of membrane lipids and signal substances. The other primary interest is the anti-oxidative compounds such as lignans, and other seed substances that have some medicinal activities, such as in anti-aging and hypocholesterolemia (Namiki 2007). Here we discuss some of the current molecular strategies to developing value-added sesame varieties, with the focus centering on these biotechnological targets within sesame seeds. In addition, we present other important biotechnological applications geared toward modulating important sesame seed byproducts, such as seed storage proteins, tocochromanols, and phytic acid. Finally, we will assess the current state of transgenic sesame plant technology.

Molecular Strategy for Genetic Improvement of Lipid Composition in Sesame Oil Sesame produces an edible oilseed indispensable to Asian cuisine. Its oil is superior in quantity and quality to that of any other (Bedigian 2000; Chung et al. 1995; Izawa 1980: 109), hence sesame is emerging as one of the most promising candidates as a seed oil food resource. Recent molecular investigation of lipid biosynthesis provides us with basic knowledge of molecular mechanisms involved in lipid biosynthesis in oilseeds. This can now be applied to molecular breeding for genetic improvement of the sesame crop (Alonso and Maroto 2000; Damude and Kinney 2008; Lung and Weselake 2006; Murphy 2006; Opsahl-Ferstad et al. 2003; Qi et al. 2004). Biotechnological applications frequently target key enzymes in the lipid biosynthetic pathways, and these genes have been cloned from a variety of other oil crops (Drexler et al. 2003; Napier 2007; Thelen and Ohlrogge 2002). De novo fatty acid synthesis begins in plastids by a condensation reaction of acetyl-CoA and malonyl-CoA as precursor materials with catalytic reactions of the fatty acid synthase complex. These plastid fatty acids synthesized are then terminated by acyl-ACP (acyl carrier protein) thioesterases, which release free fatty acids and are then reesterified to acyl-CoA esters at the plastid membrane (Figure 13.1a). Subsequently, the acyl-CoA (coenzyme A) esters are then further modified and unsaturated or elongated in the endoplasmic reticulum (ER) to synthesize triacylglycerol, polyunsaturated fatty acids, the membrane lipids, and other long-chain fatty acids by the catalytic reactions of the enzymes involved in each pathway. These enzymes are the key molecular targets for biotechnological applications in sesame seed oils. Most seed storage oils are deposited in membrane-bound organelles, termed lipid bodies, in the form of triacylglycerols synthesized through several reaction steps in the ER (Figure 13.1b). Sesame seeds consist of 45–60% lipid and 18–20% proteins (Chung et al. 1995; Izawa 1980: 109). Although sesame seeds synthesize high amounts of several major fatty acid species, their lipid composition is nutritionally deficient because of the low levels of α-linolenic acid, an essential fatty acid (Chung et al. 1995). Genetic modification of sesame using molecular breeding technology might restore this deficit. Initiating or increasing the production of specific fatty acids with higher functional values, such as α-linolenic or γ-linolenic acid, is an important goal of sesame growers and the vegetable oil industry alike (Chung 2004). Accordingly, we present several biotechnological modification strategies for enhancement of these two fatty acids in sesame seed oils.

Enhancing α-Linolenic Acid Content using ω-3 Desaturase Alpha-linolenic acid (C18:3Δ9,12,15) is a polyunsaturated fatty acid with three double bonds, at the 9th, 12th, and 15th carbon from the carboxylic end of the hydrocarbon chain (C9, C12 and C15; Figure  13.2). Alpha-linolenic acid is a fatty acid essential for human growth and development (Bjerve et al. 1992; Cunnane 1992; Okuyama 1992) in that it plays a metabolically important role in

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Molecular Biotechnology of Sesame

Plastid

(a): In plastid Acetyl-CoA + HCO3–

ACCase

FA synthase complex

Malonyl-CoA (MCA) FA synthase complex

+Acetyl-CoA

SAD

CO2

C18:0

C16:0 MCA

CO2 MCA

C14:0

CO2 MCA

CO2

C12:0

C10:0 MCA

Free FA released from acyl-ACP by thioesterases are activated to acyl-CoA esters by acyl-CoA synthase and exported into the ER

C8:0

CO2 MCA

C6:0

C16:0-CoA C18:0-CoA C18:1(∆9)-CoA

Cytosol (b): In ER

CO2

CO2 MCA

C4:0 MCA

Acyl carrier protein (ACP), β-Ketoacyl-ACP synthase, Acetyl-CoA-ACP transacetylase, Enoyl-ACP reductase, β-Hydroxyacyl-ACP dehydratase, β-Ketoacyl-ACP reductase, Malnoyl-CoA-ACP transferase

C18:1(∆9)

CO2

ER Acyl-CoA pool

+

G3-pool Acyl transferases

Glycerolipids

Formation of TAG by DGAT or PDAT Lipid body TAG

C18:2(∆9,12) by ω-6 desaturase C18:3(∆9,12,15) by ω-3 desaturase LCPUFA by ω-6, ω-3, desaturases and elongases

Figure 13.1  Simplified lipid biosynthetic pathways in plant seeds. (a): De novo fatty acid synthesis in plastids begins with three compounds—a two-carbon compound (acetyl-CoA), bicarbonate (HCO3−), and a threecarbon intermediate (malonyl-CoA)—using the catalytic reactions of ACCase and the FA synthase complex. Eight subsequent cycles of reactions synthesize fatty acids with 18 carbon units, which are released from acylACP by thioesterases, reesterified to acyl-CoA esters by acyl-CoA synthase, and exported into the ER. (b): In the ER, the exported acyl-CoA esters react with G 3-P, as mediated by acyl transferases, to produce glycerolipids. Different pathways then use glycerolipids to synthesize TAG and LCPUFA. The seed storage lipids, TAG, are then deposited in lipid bodies. Acetyl-CoA, acetyl-coenzyme A; ACCase, acetyl-CoA carboxylase; MCA, malonyl-CoA; FA, fatty acid; ACP, acyl carrier protein. In all instances, C means “carbon,” the number after the C denotes the total number of carbons in the aliphatic chain, and the number after the colon indicates the number of double bonds in the chain; for example, C4:0 is a fatty acid composed of four carbon units with no double bonds, and C18:1 (Δ9) is a fatty acid (oleic acid) containing 18 carbon units with one double bond at the 9th carbon unit. SAD, stearoyl-ACP Δ9 desaturase; G 3-P, glycerol 3-phosphate; TAG, triacylglycerol; DGAT, diacylglycerol acyltransferase; PDAT, phospholipid diacylglycerol acyltransferase; and LCPUFA, long-chain polyunsaturated fatty acid.

222

Sesame: The Genus Sesamum Linoleic acid (C18:2∆9,12) Carboxylic end Methyl end HO-CHO-CH2-(CH2)6-CH=CH-CH2-CH=CH-CH2-CH2-CH2-CH2-CH3 1 9 12 ω-3 desaturase α-Linolenic acid (C18:3∆9,12,15) Carboxylic end Methyl end HO-CHO-CH2(CH2)6-CH=CH-CH2-CH=CH-CH2-CH2=CH2-CH2-CH3 1 9 12 15

Figure 13.2  The chemical structures of linoleic acid (C18:2Δ9,12) and α-linolenic acid (C18:3Δ9,12,15). The formation of α-linolenic acid is catalyzed by ω-3 desaturase.

most living organisms, but it cannot be synthesized de novo by human metabolic processes. Alphalinolenic acid can be utilized biochemically in two ways. It is converted into longer fatty acids in the n-3 fatty acid family, such as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) (Figure 13.3), which are associated with human health benefits (Pawlosky and Salem 1992; Poulos et al. 1992; Salem and Niebylski 1992; Tamura et al. 1992). Alternatively, it enters the β-oxidation pathway in mitochondria and is used as an energy source (Barceló-Coblijn 2007; Pawlosky and Salem, Jr. 1992). Sesame lipids are composed of four major fatty acids: linoleic, oleic, palmitic, and stearic acid. Of these, about 80% are composed of oleic acid and linoleic acid. In contrast, only 0.4–0.5% of the total fatty acids are composed of α-linolenic acid (Figure 13.4), demonstrating the very low content α-Linolenic acid (C18:3∆9,12,15) Desaturase Elongase

all-cis-5,8,11,14-Eicosatetraenoic acid (C20:4∆5,8,11,14)

Desaturase

EPA(C20:5∆5,8,11,14,17)

• Antiatherogenic effects • Anti-ainflammatory effects • Reduction of cholesterol • Possible anticancer

Desaturase Elongase

DHA(C22:6∆4,7,10,13,16,129)

• Various medical roles such as antiarrhythmic effects and vascular protection • Cell growth and development • Brain and retinal function • Reduce high blood pressure and platelet-activating factor

Figure 13.3  The formation of n-3 fatty acids and their beneficial effects on human health.

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Molecular Biotechnology of Sesame 300

mg/g Dry Seed

250 200

C16:0 C18:0 C18:1 C18:2 C18:3(∆9,12,15) C18:3(∆6,9,12)

150 100 50 0

15

20

25

30 DAF

35

40

D

Figure 13.4  Histogram showing the biosynthesis and accumulation of six major fatty acids at different developing stages in sesame seeds. DAF, days after flowering.

of α-linolenic acid in sesame. Increasing the α-linolenic acid content in sesame would enhance its nutritional value, and is thus an important biotechnological target. The enzyme essential for α-linolenic acid biosynthesis is ω-3 desaturase (Figures 13.1a and 13.2), which converts linoleic acid (C18:2Δ9,12) to α-linolenic acid by introducing one double bond at the C3 position (Figure 13.2). The exact catalytic mechanism behind this fatty acid desaturation reaction is only partially understood, because this enzyme is membrane-bound and not easily isolated. However, recent molecular technology has facilitated biochemical and molecular study of this desaturase. Since ω-3 desaturase was first cloned from Arabidopsis thaliana using a map-based technology (Arondel et al. 1992), corresponding isoforms have been reported from many plant species and other organisms (Alonso and Maroto 2000; Damude and Kinney 2007). Two general types of ω-3 desaturase occur in higher plants: one in the microsomal membrane, the other in the plastid envelope, and thus are named microsomal and plastid ω-3 desaturases (Mazliak 1994). Both desaturases catalyze the same reactions, although a certain fungal ω-3 desaturase converts arachidonic acid (C20:4 Δ5,8,11,14) to eicosapentaenoic acid (EPA). The genes encoding these two desaturases, which are very similar at the nucleotide and amino acid sequence levels, have been cloned from many higher plant sources and have already been used to enhance the α-linolenic acid content of several plants: soybean (Bilyeu et al. 2003), flax (Vrinten et al. 2005), rice (Anai et al. 2003), tobacco (Hamada et al. 1998), and Arabidopsis (Shah et al. 1997). Since the microsomal ω-3 desaturases are more effective than plastid desaturases at increasing α-linolenic acid content in seeds (Browse et al. 1993), the genes encoding the microsomal desaturases present a promising target for enhancing the α-linolenic acid content in sesame seed oils. Rice seeds transformed with a microsomal ω-3 desaturase gene from soybeans (Anai et al. 2003) displayed α-linolenic acid levels that were 10-fold greater than in untransformed seeds, and stable phenotypic inheritance persisted in subsequent generations. This observation suggests that introduction of ω-3 desaturase genes could be useful in increasing α-linolenic acid in sesame oil. To create a transgenic sesame variety with high α-linolenic acid content, we isolated a microsomal ω-3 desaturase cDNA from developing Perilla frutescens (L.) Britton seeds that showed a seedspecific expression pattern (Chung et al. 1999). Using this cDNA, we constructed four different expression cassettes that drove expression of the Perilla microsomal ω-3 desaturase with a sesame-

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Table 13.1 Comparison of the Content of α-linolenic Acid between ω-3 Mutant and Transgenic Arabidopsis Seeds (mol %) Mutant

T1

T2

T3

T4

T5

T6

5.3

21.3

22.6

20.8

22.5

23.2

18.9

(a) HindIII

PstI

SeFAD2-P(660 bp)

(b)

M

T1

T2

XbaI

PrFAD3 rbs

T3

T4

T5

BamHI PrFAD3 ORF (1.25 kb)

T6

EcoRI

SeFAD2-Ter

C

2 kb

Figure 13.5  α-Linolenic acid expression cassette transformed into mutant Arabidopsis (deficient in the ω-3 desaturase gene) and the resulting transformant lines. (a) The components of the expression cassette. SeFAD2-P, sesame FAD2 promoter, which shows a seed-specific expression pattern; PrFAD3 rbs, perilla FAD3 gene ribosome binding sequence; ORF, open reading frame; and SeFAD2-Ter, sesame FAD2 terminator. (b) Confirmation of introduction of the PrFAD3 ORF into the transformant lines (T1 to T6 and C, control) by Southern analysis (upper). Northern blot data (lower) show successful expression of the PrFAD3 gene in the transgenic Arabidopsis seeds.

seed-specific promoter and other regulatory elements. To evaluate the expression capability of these ω-3 desaturase cassettes, we introduced them into a mutant Arabidopsis deficient in α-linolenic acid synthesis (Table 13.1). We subsequently identified several transgenic Arabidopsis lines whose α-linolenic acid production was driven by the expression cassette (Figure 13.5). We are currently evaluating the ω-3 desaturase expression of the resulting sesame transformants, generated by transforming cotyledon explants with a soil bacterium (Agrobacterium tumefaciens) that harbored the ω-3 desaturase expression cassette.

Enhancing γ-Linolenic Acid Content using Δ-6 Desaturase Gamma-linolenic acid is synthesized by an enzyme of Δ-6 desaturase (Figure 13.6) and is the common precursor to the synthesis of the n-6 family of polyunsaturated fatty acids, such as arachidonic acid (Figure 13.7). In particular, the beneficial pharmaceutical effects of γ-linolenic acid, such as skin conditioning, reduction of general inflammation, prevention of certain cancers, and other benefits, have attracted many researchers to biotechnological Δ-6 desaturase applications that might increase the γ-linolenic acid content in oilseeds (Das et al. 2001). Biosynthesis of plant γ-linolenic acid by Δ-6 desaturase (Figure 13.6) was first reported in common borage (Borago officinalis L.) by Stymne and Stobart (1986). Since then, many others have examined the biochemical mechanisms and nutritional functions of γ-linolenic acid (Galle et al. 1997; Horrobin 1993; Lee et al. 1998; Sayanova et al. 2001). Recently, several groups have made

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Molecular Biotechnology of Sesame C18:0 Stearic acid Stearoyl-ACP desaturase C18:1(∆9) Oleic acid

ω-6 desaturase

ω-3 desaturase

C18:3(∆9,12,15) α-Linolenic acid

∆-6 desaturase

∆-6 desaturase C18:2(∆6,9) Unusual fatty acid

C18:2(∆9,12) Linoleic acid

ω-6 desaturase

C18:3(∆6,9,12) γ-Linolenic acid

Figure 13.6  Representative pathways of polyunsaturated fatty acid biosynthesis by fatty acid desaturases.

attempts to metabolically engineer the fatty acid composition of oil crops using desaturases (Kinney et al. 2002; Thelen and Ohlrogge 2002). To date, a number of genes encoding Δ-6 desaturases have been deposited into gene libraries and manipulated in order to genetically enhance nutritional or industrial value in oilseed crops such as soybean and rapeseed (Damude and Kinney 2008; Dyer and Mullen 2008; Napier 2007). Expression of Δ-6 desaturase genes effectively enhanced the content of γ-linolenic acid in tobacco (Reddy and Thomas 1996; Sayanova et al. 1997; Garcia-Maroto et al. 2002; Zhou et al. 2006), Brassica juncea L. (Hong et al. 2002; Qiu et al. 2002), soybean (Sato et al. 2004), and other plant species (Chen et al. 2005). Introducing two desaturases (Δ-6 and Δ-12 desaturase) into transgenic canola increased the γ-linolenic acid content by as much as 43% compared to wild-type canola (Flider 2005). This result indicates that co-expression approaches may be much more efficient in enhancing γ-linolenic acid than expression of a single gene. γ-Linolenic acid (C18:3∆6,9,12)

∆6 Elongase Dihomo-γ-Linolenic acid (C20:3∆8,11,14)

∆5 Desaturase Arachidonic acid (C20:4∆5,8,11,14)

• Infant nutrition • Anti-inflammatory effects • Improvement of atopic eczema • Hypotensive effect • Potential mediator of various health and diseases

Figure 13.7  The biosynthetic pathway and nutritional and medical benefits of arachidonic acid.

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RB

SeFAD2 promotor

∆-6 ORF

Nos-T

LB

pCAMBIA3301 (11307 bp)

Figure 13.8  The expression cassette of Δ-6 desaturase for production of γ-linolenic acid in sesame oilseeds. This construct was inserted into a plant vector, pCAMBIA 3301, with the bar gene as a selectable marker. RB, right border; SeFAD2, sesame FAD2 gene; Δ-6 ORF, Δ-6 desaturase (Figure 13.7) open reading frame.

Figure 13.4 illustrates the fact that sesame produces no γ-linolenic acid. This limits its nutritional quality. Therefore, the expression of Δ-6 desaturase has been one of our key genetic targets (Chung 2004). In our laboratory, we constructed an expression cassette consisting of a borage Δ-6 desaturase gene under control of a sesame-seed-specific promoter (Figure  13.8). We then transformed sesame cotyledon explants using Agrobacterium tumefaciens harboring the cassette. The expression vector successfully integrated into the sesame tissues, as demonstrated by a positive signal for borage Δ-6 desaturase by PCR (polymerase chain reaction) analysis, and the transformants are currently under investigation.

Molecular Strategy for Genetic Improvement of Tocochromanols in Sesame Seeds Oilseeds are the main dietary source for vitamin E, but most seed oils contain a biased composition of toco-isomers (8 toco-isomers: α-, β-, γ- and δ-tocopherol plus α-, β-, γ- and δ-tocotrienol), collectively termed tocochromanols, which have a strong vitamin E activity, expressing proportionally more of some than of others (Bramley et al. 2000). Much attention has been paid to tocochromanols recently, as they induce important physiological responses in humans and plants (Figure  13.9). Supplemental tocochromanol reduces membrane lipid peroxidation and electrolytic leakage in plants, two common symptoms of oxidative stress. These responses are due to the strong antioxidant activity of vitamin E through the action of tocochromanols (Abbasi et al. 2007; Dörmann 2007). Vitamin E is an essential nutrient with multi-functional effects on human growth, development, general health, and disease prevention (Bramley et al. 2000; Schneider 2005). Sesame seeds are richest in γ-tocopherol among the 8 toco-isomers (Table 13.2), which suggests that increasing the production of other toco-isomers in sesame might not only enhance its nutritional functionality in humans, but also protect against oxidative stress in the sesame plant itself. Recent advances in molecular and transgenic technology allow us to modify the tocochromanol composition in oilseed crops by metabolically engineering their biosynthetic pathways (Bramley et al. 2000; Schneider 2005). A prerequisite for metabolic tocochromanol engineering in oilseeds is the identification and cloning of the key enzymes in the tocochromanol biosynthetic pathways, such as vitamin E 1-4 and other relevant enzymes (Figure 13.10). Many genes encoding these enzymes have now been isolated from various organisms and applied to metabolically augment or to modify the tocochromanol content and composition of oilseeds. Since the eight tocochromanol isomers each have distinct physiological effects as biological mediators (Sen et al. 2006), engineering a balanced tocochromanol composition in oilseeds could be a useful molecular target for enhanced vitamin E activity.

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R3

R1 O

CH3

CH3 CH3

HO

Tocopherol

R2 R3

CH3

CH3

R1 O

CH3

CH3

CH3

CH3 CH3

HO R2

Tocotrienol

R1

R2

R3

α-tocopherol β-tocopherol γ-tocopherol δ-tocopherol

–CH3 –CH3 –CH3 –CH3

–CH3 –CH3 –H –H

–CH3 –H –CH3 –H

α-tocotrienol β-tocotrienol γ-tocotrienol δ-tocotrienol

–CH3 –CH3 –CH3 –CH3

–CH3 –CH3 –H –H

–CH3 –H –CH3 –H

Figure 13.9  The chemical structures of the 8 toco-isomers: α-tocopherol, β-tocopherol, γ-tocopherol, δ-tocopherol, α-tocotrienol, β-tocotrienol, γ-tocotrienol, and δ-tocotrienol.

Table 13.2 Contents of Tocochromanols in Sesame Oils (mg/kg) Toco-isomers

Content

α-tocopherol β-tocopherol γ-tocopherol δ-tocopherol α-tocotrienol β-tocotrienol γ-tocotrienol δ-tocotrienol

  12.6 trace 312.7 trace — — — —

Enhancing α-Tocopherol Content in Sesame using γ-Tocopherol Methyltransferase (γ-Tmt) Sesame seeds synthesize high amounts of γ-tocopherol but not α-tocopherol (Table  13.2), possibly because of low activity or deficiency of the γ-TMT gene. Thus enhancement of α-tocopherol in sesame seeds is an important genetic target because of its high nutritional value for human health. Gamma-tocopherol methyltransferase (γ-TMT) catalyzes the conversion of γ-tocopherol into α-tocopherol. It transfers a methyl group from S-adenosylmethionine to γ-tocopherol, and is the key enzyme target for metabolic manipulation of the α-tocopherol content of crop plants (Figure 13.10). The biochemical properties of γ-TMT have been characterized in Capsicum annum L., Arabidopsis thaliana, and Euglena gracilis (d’Harlingue and Camara 1985; Koch et al. 2003; Shigeoka et al. 1992). Subsequently, Shintani and DellaPenna mediated the first successful genetic manipulation of α-tocopherol expression using γ-TMT from Arabidopsis (Shintani and DellaPenna 1998); they reported a >80-fold increase in α-tocopherol levels in transgenic Arabidopsis seeds without changing the total amount of tocopherols in the seeds. More recent findings regarding the molecular manipulation of γ-TMT genes provide some important insight into using biotechnological strategies to enhance the α-tocopherol content in transgenic oilseeds. Transforming soybean and Perilla with γ-TMT genes under the control of seed-specific promoters mediated dramatic increases in α-tocopherol levels in the transgenic seeds (Lee et al. 2008; Tavva et al. 2007). In particular, co-expression of γ-TMT and 2-methyl-6-phytylbenzoquinol

228

Sesame: The Genus Sesamum HGA (from shikimate pathway and tyrosine catabolism)

HGGT

HPT

MGGBQ

MPBQ

Cyclization reaction by TC

γ-Tocotrienol and δ-Tocotrienol γ-TMT α-tocotrienol

γ-TMT β-tocotrienol

γ-tocopherol and δ-Tocopherol γ-TMT α-Tocopherol

γ-TMT β-Tocopherol

Figure 13.10  Key tocopherol and tocotrienol biosynthetic pathways. The bold-lettered enzymes are the major biotechnological targets for molecular modification to enhance the tocochromanol content in sesame oilseeds. HGA, homogentisic acid; HGGT, homogentisate geranylgeranyltransferase; HPT (VTE2), homogentisate phytyltransferase; MGGBQ, 2-methyl-6-geranylgeranyl-1,4-benzoquinol; MPBQ, 2-methyl-6-phytyl1,4-benzoquinol; TC, tocopherol cyclase (VTE1); and γ-TMT, γ-tocopherol methyltransferase (VTE4).

(MPBQ) methyltransferase from Arabidopsis greatly increased the α-tocopherol content in transgenic soybean seeds (Van Eenennaam et al. 2003). We are currently transforming sesame with a γ-TMT cDNA isolated from developing sunflower seeds (GenBank accession number: EF495160) to promote the conversion of the richly abundant γ-tocopherol to α-tocopherol. This higher α-tocopherol content in transgenic sesame seeds should improve the functionality of sesame by conveying a higher nutritional value.

Enhancing Tocochromanol Content of Sesame Seeds Aside from γ-tocopherol, other tocochromanols are undetectable or present only in trace amounts in sesame seeds (Table 13.2), indicating the need of genetic improvement to enhance their nutritional value. To boost production of these toco-isomers in other oil crops, many researchers have focused on key enzymes in their biosynthetic pathways (Figure  13.10). These enzymes include tocopherol cyclase, homogentisate phytyltransferase (HPT1), homogentisate prenyltransferase (HPT2), 2-methyl-6-phytylbenzoquinol (MPBQ) methyltransferase, and homogentisate geranylgeranyltransferase (HGGT). Because these enzymes are essential for catalyzing the committed steps in several of the tocochromanol biosynthetic pathways, their genes have been molecular targets for genetically improving tocochromanol production in many crop plants (DellaPenna and Last 2006; Sen et al. 2006; Valentin and Qi 2005). Generally, the metabolic engineering strategy used to enhance the tocochromanol contents in oilseeds consists of overexpressing their biosynthesis genes in transgenic plants using single- or double-transgene expression systems (DellaPenna and Last 2006; Karunanandaa et al. 2005). In transgenic Brassica oilseeds, overexpression of tocopherol cyclase, alone or with co-expression of homogentisate phytyltransferase or other key enzymes, increased the tocochromanol content by 20–50% (Kumar et al. 2005; Raclaru et al. 2006). In a transgenic soybean expressing Arabidopsis

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MPBQ methyltransferase, the contents of α- and γ-tocopherol increased (Van Eenennaam et al. 2003). Other research groups (Sadre et al. 2006; Savidge et al. 2002) also mediated 1.5- to 2-fold increases in total tocopherol levels within transgenic Arabidopsis seeds by overexpressing homogentisate phytyltransferase or homogentisate prenyltransferase. In the case of metabolic tocotrienol engineering, homogentisate geranylgeranyltransferases, the primary enzymatic contributors to tocotrienol formation, were cloned from barley, wheat, and rice seeds. When one of these genes was overexpressed in corn seeds, both the tocotrienol and tocopherol contents increased by as much as 6-fold (Cahoon et al. 2003). These results provide us with important information concerning tocochromanol engineering in sesame. To begin, we started with tocochromanol-rich plants and cloned several of their genes encoding key tocochromanol biosynthesis enzymes, and we have characterized their recombinant products (our unpublished data). We expect that reports of transgenic sesame producing high tocochromanols may emerge quickly as a result of this work.

Molecular Strategy for Genetic Improvement of Sesame Storage Proteins Seed storage proteins of grain crops are a major part of the human diet, but sesame seed proteins are often used as poultry and livestock feed after the seed oil has been extracted. The proteins make up approximately 18–20% of sesame seed dry weight. Two major storage proteins, 11S and 2S albumin, are 60–70% and 15–25% of the total sesame proteins, respectively (Hsiao et al. 2006; Tai et al. 1999). Using expressed sequence tags (ESTs) from developing sesame seeds, researchers have isolated four 11S globulin and three 2S albumin isoforms and identified their corresponding proteins by MALDI-MS (matrix-assisted laser desorption-ionization mass spectrometry) analyses. However, genetic information concerning the 7S globulin has not emerged (Hsiao et al. 2006; Suh et al. 2003). Although the sesame seed storage proteins identified contain amino acid compositions rich in methionine, cysteine, arginine, and leucine, which are essential amino acids in human and animal diets (Hasegawa et al. 1978), some storage proteins of sesame seeds such as 11S globulin, 7S globulin, and 12S albumin have been reported as the major sesame seed allergens (Beyer et al. 2002, 2007; Wolff et al. 2003). In addition, oleosins, which are present in oil bodies, are also recognized as a new class of allergens in sesame seeds (Leduc et al. 2006). As a result, food products containing sesame are among the most allergenic foods (Gangur et al. 2005). Using transgenic sesame plant technology, therefore, it might be possible to remove or alter the allergenic epitopes in sesame seed storage proteins and oleosins using protein engineering, thereby generating transgenic sesame seeds with reduced allergenicity.

Molecular Manipulation of Phytic Acid in Sesame: Role of Myoinositol 1-Phosphate Synthase Phytic acid (myoinositol 1,2,3,4,5,6-hexakis phosphoric acid) is generally stored as a salt (phytate) and functions as a storage phosphate in various plant seeds. Phytic acid is composed of six phosphate groups in a myoinositol ring (Figure 13.11). The functions of phytic acid are diverse (Oatway et al. 2001), but most notably it is a strong chelating agent for divalent minerals such as copper, calcium, magnesium, zinc, and iron. This chelating ability has raised concerns regarding phytic acid levels in animal and human nutrition, presumably because excess phytic acid might result in low mineral bioavailability (Weaver and Kannan 2002). In contrast, phytate does have some positive properties, including anticancer activity, a cholesterol-lowering effect, and other medical benefits that could mediate protection against cardiovascular and other human diseases (Oatway et al. 2001; Urbano et al. 2000). For a comprehensive review of the biological effects and applications of phytate, see Reddy and Sathe (2002). In the livestock and fishery industries, the presence of phytate in feed

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OPO3H2 OPO3H2

H2PO3O

OPO3H2 OPO3H2

Figure 13.11  Chemical structure of phytic acid.

Table 13.3 Contents of Phytic Acid in Dry Seeds of Various Crops Source Sesame Flax Cotton Canola Castor bean Soybean Peas

Content (%) 4.71 3.69 2.94 2.50 2.16 1.55 1.00

Source: Data were selected from a review paper by Lott et al. 2000, Seed Science Research 10: 11–33.

presents a major problem for monogastric animals (poultry, swine, and fish), because they do not digest phytate. They instead excrete the phytate contained in their feed without degrading it, leading to phosphorus pollution and eutrophication of surface waters (Raboy et al. 2002). Accordingly, this problem has generated interest in molecular approaches to lowering the phytic acid in seed crops used in livestock feed (Feng and Yoshida 2004; Guttieri et al. 2004; Raboy 2002). Sesame seed pomace (the residue after extraction of oil by crushing toasted sesame seeds) is used as feed for monogastric livestock. This practice may contribute to a toxicity problem because of the high content of phytic acid in sesame seeds (Table 13.3). One biotechnological approach to solving this problem is to create sesame seeds with lower phytic acid expression using molecular technologies that suppress gene expression, such as antisense or RNAi (RNA interference). It is possible with these techniques to target and down-regulate the expression of genes involved in the biosynthesis of phytic acid (Feng and Yoshida 2004; Nunes et al. 2006; Tang and Galili 2004). One candidate enzyme is myoinositol 1-phosphate synthase, the enzyme that catalyzes the committed step in phytic acid biosynthesis (Loewus and Murthy 2000; Raboy et al. 2002). Recently, we isolated and characterized the gene encoding myoinositol 1-phosphate synthase in developing sesame seeds (Chun et al. 2003). Using this gene, we constructed an antisense expression cassette in order to generate transgenic sesame seeds with lower phytate expression. We are currently applying this construct to sesame and other feed crops.

Potential for Biotechnological Modification of Lignan Content in Sesame Seeds Sesamin has long been an interesting candidate as a dietary supplement because of its potent antioxidant effects and its ability to enhance the anti-inflammatory effects of essential fatty acids (Armour

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and Sambasiva 1995). It has also lowered total cholesterol and low-density lipoprotein (LDL) levels, elevated plasma γ-tocopherol, increased the activity of vitamin E, and reduced inflammatory processes known to promote cancer and aging (Coonev 2001; Miyahara et al. 2001; Shimizu et al. 1991). Sesame seeds contain between 0.5% and 1.0% sesame lignans by dry weight, primarily sesamin, sesamolin, sesaminol, and sesamolinol. The biosynthetic pathway of lignans in developing sesame seeds was unraveled by administration of radio-labeled and stable-isotope-labeled precursor molecules (Jiao et al. 1998; Kato et al. 1998). [1-14C]tyrosine is converted into coniferyl alcohol by the phenylpropanoid pathway. Two coniferyl alcohol molecules are subsequently coupled to pinoresinol; then pinoresinols are converted into “oxygen-inserted” lignans (sesamolin or sesamin) via a piperitol molecule containing a single methylenedioxy bridge. Recently, EST candidates corresponding to each enzyme in the sesame lignan biosynthetic pathway were isolated from 3328 developing sesame seed ESTs (Suh et al. 2003). For the biosynthetic pathway that converts tyrosine to coniferyl alcohol, this study revealed ESTs corresponding to all but one of the enzymatic steps (cinnamate-4-hydroxylase, flavonoid-3-hydroxylase, coumaric acid hydroxylase, caffeic acid O-methyltransferase, caffeoyl-CoA O-methyltransferase, CoA ligase, cinnamoyl-CoA reductase, and cinnamyl-alcohol dehydrogenase; tyrosine ammonia-lyase was the lone exception). In addition, this study identified several ESTs encoding a dirigent protein that is involved in the formation of pinoresinol from coniferyl alcohol using bimolecular phenoxy radicals. The study also isolated a cytochrome P450-dependent enzyme, which uses O2/NADPH to form a methylenedioxy bridge and insert one oxygen atom during the synthesis of sesamin and sesamolin from pinoresinol. Despite progress in identifying the biosynthetic lignan pathway genes in sesame, most of the enzymes in these pathways are not yet characterized, owing to difficulties in protein purification. Further elucidation of the biosynthetic mechanism of sesame lignan production will probably enable us to produce high quality sesamin as a dietary supplement.

Development of Non-Shattering Sesame Varieties Shattering is one of the most serious hindrances to sesame seed yield: as much as 50% of sesame seeds are lost through shattering, which makes mechanical harvesting problematic. The expense of the necessary manual harvest constitutes about 70% of the total production cost of sesame cultivation (Khidir 1972). For this reason, genetic development of a non-shattering sesame variety is a desirable objective. Recently, shattering-resistant sesame mutants, without the undesirable properties (semi-sterility, cupped leaves, twisted stems, short capsules, or low yields) of previously developed indehiscent sesame mutants, were developed by extensive breeding programs (Langham and Wiemers 2002). Therefore, concomitant development of mechanical seed harvesting and non-shattering sesame varieties could not only reduce labor costs but also increase seed yields. In support of conventional breeding techniques used to develop non-shattering sesame cultivars, researchers have made great progress in identifying the molecular mechanisms underlying fruit dehiscence in Arabidopsis (A. thaliana) and rice (Oryza sativa). Recent studies have isolated the MADS (MCM1, AGAMOUS, DEFICIENS and SRF) box genes SHATTER-PROOF1 (SHP1), SHATTER-PROOF2 (SHP2), and FRUITFULL (FUL), which regulate dehiscence zone (DZ) formation (Liljegren et al. 2000; Ferrandiz et al. 2000). The shp1 shp2 double mutant siliques cannot shatter after fruit desiccation (Liljegren et al. 2000). Conversely, fruits from transgenic plants overexpressing the FUL gene are indehiscent owing to a complete lack of DZ differentiation (Ferrandiz et al. 2000). When the FUL gene was transformed into Brassica juncea, the pods from the transgenic plants were resistant to shattering (Ostergaard et al. 2006). The qSH1 gene in rice encodes a BEL1type homeobox gene that is a major quantitative trait locus of seed shattering. This gene was isolated by a QTL (quantitative trait locus) analysis between a shattering-type indica cultivar, ‘Kasalath,’ and a non-shattering type japonica cultivar, ‘Nipponbare.’ Subsequent investigation revealed that a

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single-nucleotide polymorphism (SNP) in the 5′ regulatory region of the qSH1 gene mediated resistance to seed shattering, owing to a defect in abscission layer formation (Konishi et al. 2006). The lessons learned from this transcriptional mechanism that controls fruit dehiscence in model plants has the potential to support the genetic engineering of a non-shattering sesame variety.

Seed-Specific Promoters for Sesame Biotechnology Current goals of sesame biotechnology include generating transgenic seeds with improved nutritional and/or functional qualities, such as a modified seed oil composition or decreased allergenicity. To achieve such goals, seed-specific promoters show promise in that they drive expression of the target gene exclusively in the seeds of transgenic plants. Previous studies have extensively employed the napin storage protein promoter from Brassica napus to genetically modify dicotyledonous plants (Poirier et al. 1999; Rezzonico et al. 2004). Paine et al. (2005) introduced the rice glutelin promoter in monocotyledons. The promoter of the Arabidopsis fatty acid elongase gene (FAE-1), which is involved in the biosynthesis of very-long-chain fatty acid (VLCFA), was isolated and reported to be useful for genetically engineering seed oil composition (Rossak et al. 2001). During our previous studies in sesame, we isolated the promoter driving the expression of the seedspecific microsomal ∆-12 desaturase gene (SeFAD2), whose gene product inserts a double bond between C12 and C13 of the sn-1 and sn-2 oleic acids in phosphatidylcholine (Jin et al. 2001; Kim et al. 2006). When we introduced a β-glucuronidase (GUS) reporter gene under the control of this seed-specific promoter into Arabidopsis plants, GUS expression was restricted to the mid- and late developmental phases of the seeds, corresponding to the onset of storage lipid accumulation (Kim et al. 2006). In Arabidopsis, ectopic expression of a perilla linoleic acid desaturase under control of the seed-specific SeFAD2 promoter increased the oleic acid and linoleic acid contents and reduced the linolenic acid content of the seed oils (our unpublished data). We also confirmed that microprojectile bombardment successfully mediated transient expression of the GUS gene under the seed-specific SeFAD2 promoter in developing sesame, soybean, and corn seeds (Kim et al. 2008).

Potential for Molecular Pharming/Farming by Sesame Hairy Root Cultures The industrial importance of molecular pharming/farming, a molecular technology for biotechnological application for the synthesis of commercial products such as pharmaceuticals, specialty chemicals, and other bio-products, has been emphasized in plant-based production systems (Shadwick and Doran 2004; Slater et al. 2003). One of the more efficient plant-based production systems, the hairy root culture system has some advantages over other systems, including easy acquisition of roots genetically transformed by Agrobacterium rhizogenes, relatively fast growth rates of the hairy roots, growth of the hairy roots with no addition of growth regulators to their cultures, a relatively easy recovery and purification from their culture medium, and stable products produced in their culture medium (Giri and Narasu 2000; Guillon et al. 2006). The general strategy for producing foreign proteins in the hairy root system is three-fold. First, the desired gene expression vector is transformed in Agrobacterium rhizogenes. Next, the plant tissue is inoculated with Agrobacterium harboring the expression vector. Finally, the tissue forms hairy roots that express the foreign proteins, and these hairy roots are subsequently established as a stable culture system. Previously, some foreign proteins have been produced by hairy root bioreactor systems (Shadwick and Doran 2004). However, the hairy root system has a major limitation in the production of recombinant proteins: proteins expressed in the hairy roots are not secreted readily into the culture medium, but remain within the root tissues. This aspect of the system necessitates a sometimes problematic recovery step, resulting in lower protein yields from the cultures. Of course this recovery process adds to the cost of the product.

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This problem can be minimized by manipulating the gene expression vector or by optimizing the hairy root culture conditions—by increasing the dissolved oxygen tension or changing the oxygen transfer rates in the culture reactor, for example (Shadwick and Doran 2004; Sharp and Doran 2001). Jin et al. (2005) described a model system for producing a commercially valuable enzyme, a recombinant fungal phytase that catalyzes the removal of phosphorus from the phytic acid molecule (Figure 13.11), using an efficient sesame hairy root culture system. To promote release of the recombinant phytase enzyme into the liquid medium of the sesame hairy root cultures, a secretionsignaling peptide was engineered into the phytase expression vector. As a consequence, approximately 70–80% of the recombinant phytase was released into the liquid medium, greatly facilitating its recovery (Jin et al. 2004). Furthermore, the study evaluated various culture parameters to identify the conditions that maximized productivity of the recombinant fungal phytase. Specifically, the study applied several abiotic elicitors (polyethylene glycol [PEG], silver nitrate, and potassium phosphate) and determined their optimal concentrations for combination therapy (Figure  13.12). This hairy root culture system might be applicable to molecular pharming/farming for production of such valuable substances as antibodies, vaccines, and other pharmaceutically related proteins (Chun et al. 2007). However, the hairy root culture technology is still in its infancy, and extensive further development is necessary prior to any attempts to scale up applications.

Progress in Transgenic Technology of Sesame Traditional breeding techniques are constrained by limited genetic variability within germplasm. Further development of new sesame cultivars with biotic/abiotic resistance and specific functional characteristics require approaches that extend beyond breeding techniques, and emerging biotechnological methods present some promising alternatives. For these technologies to be applicable, sesame must lend itself to one or more of the prerequisite techniques, such as regeneration, genetic transformation by Agrobacterium, or direct delivery of genes into plant cells. Unfortunately, to date there have been no reports of the successful production of a transgenic sesame plant, largely because of the limited information concerning the sesame regeneration system. Although sesame has been very recalcitrant to in vitro regeneration thus far, several studies have mediated regeneration through somatic embryogenesis (Mary and Jayabalan 1997; Xu et al. 1997) and organogenesis (Seo et al. 2007; Were et al. 2006). As a rule, in somatic embryogenesis the embryogenic callus is produced from explants, and the somatic embryos are subsequently formed from the callus. A research group (George et al. 1987) obtained a callus from sesame explants, but they were able to produce only embryo-like structures from a hypocotyl-derived callus. Some years later, other groups (Mary and Jayabalan 1997; Xu et al. 1997) yielded somatic sesame embryos from hypocotyl- and cotyledon-derived calli. The calli were induced on Murashige and Skoog (1962) medium containing 2 mg/L 2,4-D (2,4-dichlorophenoxyacetic acid). Embryos appeared on the callus surface when the calli were cultured on a B5 medium containing 0.5 mg/L 2,4-D or NAA (α-naphthaleneacetic acid), 0.5 mg/L BA (N6-benzyladenine) and 0.5 % casein hydrolysate. For plantlet conversion, the embryos were cultured on B5 medium with 0.5% activated charcoal, followed by transfer to half-strength MS medium with 0.1 mg/L zeatin. However, the conversion rate from somatic embryos was very low. Alternatively, recent reports document plant regeneration in sesame via direct and indirect adventitious shoot organogenesis. One study documented direct shoot organogenesis from deembryonated cotyledon explants derived from sesame seeds (Seo et al. 2007). Other researchers (Moon 2004; Were et al. 2007) established an in vitro regeneration system using seedling cotyledon and hypocotyls explants. Other studies achieved low-frequency indirect adventitious shoot regeneration from hypocotyl and/or cotyledon explants (Kwon et al. 1993; Rao and Vaidyanath 1997; Taşkin and Turgut 1997). In these reports, shoot regeneration frequency in sesame organogenesis is influenced by genotype, explant source, medium composition, and the presence of plant growth regulators.

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Figure 13.12  Effects of abiotic factors on sesame hairy root growth and recombinant fungal phytase production. P170 and P340 denote phosphate concentrations of 170 mg/L and 340 mg/L, respectively, in the culture medium.

Regarding the effect of explant source, the deembryonated cotyledon explants from mature seeds mediated direct shoot organogenesis with higher frequency than those from immature seeds and 1- to 2-week-old seedlings (Seo et al. 2007). Some workers (Moon 2004; Seo et al. 2007) achieved direct adventitious shoot formation from sesame cotyledon explants in MS medium by adding relatively high concentrations of plant growth regulators, such as BA (5–10 mg/L), IAA (indole-3-acetic acid) or IBA (indole-3-butyric acid) (0.3–1.0 mg/L), and ABA (1.0–2.0 mg/L). Composition of the basal medium was also important for adventitious shoot formation in sesame. Half-strength MS medium or N6 medium (Chu et al. 1974) supplemented with a combination of IBA and either BA or TDZ (thidiazuron) was optimal for direct shoot formation in sesame (Were et al.

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Figure 13.13  Plant regeneration procedures using adventitious shoot organogenesis from cotyledon and sesame seedling hypocotyl explants.

2007). Interestingly, Seo et al. (2007) demonstrated that pre-culturing cotyledon explants in a high sucrose concentration (6% or 9%) for 2 weeks enhanced the shoot regeneration frequency. The sesame genotype also influenced the formation of adventitious shoots; cultivars 8 and 15 formed adventitious shoots with frequencies of 39% to 63% (Were et al. 2007) and 3.3% to 80.6% (Moon 2004), respectively. Our group developed an efficient direct organogenesis protocol using hypocotyl and cotyledon explants from 15 sesame cultivars (Figure  13.13). When we cultured explants obtained from 6- to 7-day-old seedlings on shoot regeneration medium, direct adventitious shoots formed at the cut regions after 4 to 6 weeks. We subsequently elongated and multiplied the regenerated shoots, successfully rooted them, and acclimatized the plantlets to artificial soil (our unpublished data). Using an indirect shoot organogenesis process, a research group (Kwon et al. 1993) initially induced the callus from the explants, and then generated adventitious shoots from the callus. They efficiently obtained callus formation from hypocotyl explants on medium containing 0.2–0.6 mg/L BA and 1–2 mg/L NAA. Adding 1–2% casein hydrolysate to the regeneration medium with 1–4 mg/L BA and 0.1 mg/L NAA effectively increased the rate of adventitious shoot formation from hypocotyl-derived calli, and the resulting shoots were rooted on half-strength MS medium with 0.5 mg/L NAA. To date, no one has reported producing transgenic sesame plants using genetic transformation with Agrobacterium tumefaciens. However, we and other researchers have used Agrobacterium rhizogenes to produce transformed sesame hairy roots from explants (Chun et al. 2007; Jin et al. 2005; Ogasawara et al. 1993), although the roots failed to regenerate a complete plant. Previous work has demonstrated that sesame is susceptible to Agrobacterium tumefaciens infection, and cotyledon explants infected with wild-type A. tumefaciens A281 and other strains produced some tumor tissues (Taşkin et al. 1999). Kanamycin is the antibiotic used to select transformed cells and tissues harboring the neomycin phosphotransferase II (NPTII) gene. In this system, 50 mg/L kanamycin was optimal for the selection of sesame-transformed cells obtained by inoculation with a disarmed A. tumefaciens strain LBA4404 harboring pBI121. The transformed cotyledon explants produced calli but failed to form any adventitious shoots. Thus far in our laboratory, we produced GFP-expressing transgenic sesame plants using an Agrobacterium tumefaciens–mediated transformation system. In this system, we inoculated

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Seeding & Germination 7 days, GM (germination medium) Inoculation with Agrobacterium 20 min, SM (shoot induction medium) Cocultivation 3 days, SM with 100 µMAS Selection (Callus & Shoot formation) 4–8 months, TSM (selection medium) Shoot elongation & rooting 1–2 months, TRM (rooting medium) Assay GFP, PCR, and Southern analysis Transgenic plant

Figure 13.14  Procedures for Agrobacterium-mediated transformation and production of transgenic plants via indirect adventitious shoot organogenesis in sesame.

cotyledon and hypocotyl explants with an A. tumefaciens strain LBA4404 that harbored pBINmGFP5-ER, a cassette containing a nptII gene, and a modified jellyfish green fluorescent protein (GFP) gene fused to an ER (endoplasmic reticulum)-targeting sequence (mGFP5-ER).Following co-cultivation of the explants and bacteria for 2 to 3 days, we cultured the explants on a selection and shoot regeneration medium (MS medium with 5–10 mg/L BA, 0.3–0.5 mg/L IBA, 1.0 mg/L ABA, 2.5–5.0 mg/L AgNO3, 30 mg/L kanamycin, and 500 mg/L cefotaxime or sulbenicillin). After 2 to 4 months of culture in the selection medium, calli formed in the cut regions of the transformed explants. After successive transfers of the calli to fresh selection medium, some adventitious shoots formed from the calli, and these putatively transformed shoots were successfully rooted and acclimatized to soil. They are currently being cultivated in the greenhouse for production of their progeny (Figure 13.14). We subsequently confirmed the introduction and expression of both the nptII and gfp genes in the putative transgenic plants using PCR (polymerase chain reaction) and GFP fluorescence analysis. In the PCR analysis of transformed plants, we identified bands of predicted size (Figure 13.15). In addition, we have also successfully used this technique to produce transgenic plants with a high α-linolenic acid content in their seeds. Specifically, we regenerated several FAD3-expressing transgenic plants using A. tumefaciens EHA105 harboring an expression cassette designed to boost production of α-linolenic acid (Figure 13.6). We have multiplied and acclimatized the FAD3 transgenic lines, but the transformation efficiency in sesame is insufficient to fully analyze the transgenic lines and develop new cultivars. This hurdle can be overcome only by further efforts to increase transformation efficiency in sesame.

Summary Sesame is a promising target oil crop for future biotechnological applications, in that sesame contains a number of substances that are important for human health and nutrition, such as quality vegetable oils and strong antioxidants. Nonetheless, there are also some disadvantages of these sesame constituents. We describe several biotechnological goals and several possible strategies for

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Figure 13.15  Confirmation of nptII and gfp gene introduction and expression in putative sesame transformants. (A) Agarose gel electrophoretic analysis of PCR products from nptII and gfp genes. Lane markers: M, 1-kb ladder (Gibco BRL Co.); C, control (non-transformed shoots); P, amplified product from plasmid; 1–4, putative transformants 1–4. (B) GFP fluorescence analysis of calli and shoots produced from transformed explants.

their genetic manipulation to develop new sesame varieties with higher nutritional and/or functional values. These include the genetic improvement of seed shattering and the production of transgenic sesame for molecular pharming/farming purposes using a sesame hairy root culture system. Several efforts currently focus on establishing transgenic sesame lines expressing foreign genes to improve the composition of sesame seed oils. We expect that biotechnologically improved sesame varieties will emerge in the near future. We also anticipate that before long, sesame hairy root technology may be universally available for generating industrially beneficial substances.

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of Sesame to 14 Responses Plant Growth Regulators, Micronutrients, and Salinity M. Prakash Contents Introduction..................................................................................................................................... 245 Effect of Plant Growth Regulators and Micronutrients on Germination........................................246 Effect of Plant Growth Regulators and Micronutrients on Growth Attributes................................246 Effect of Plant Growth Regulators and Micronutrients on Biochemical Parameters..................... 247 Effect of Plant Growth Regulators and Micronutrients on Yield and Yield Attributes................... 249 Effect of Plant Growth Regulators and Micronutrients on Sesame Tissue Culture........................ 250 Response of Sesame to Salinity and Modulating Impact of Growth Regulators............................ 250 Conclusions and Prospects.............................................................................................................. 251 Acknowledgments........................................................................................................................... 252 References....................................................................................................................................... 252

Introduction Sesame (Sesamum indicum L.) is an important oilseed crop of semiarid regions. It is distinctly superior to other oilseed crops because of its high degree of drought tolerance and wide adaptability to varied agro-climatic conditions. Some constraints to sesame cultivation are excessive vegetative growth, lodging, improper flower production, and poor capsule set. The main hindrances to increasing sesame productivity are flower drop and poor seed filling, which seem to be associated with nutrient deficiency and hormonal imbalance, leading ultimately to reduction in translocation of photosynthates to the sink. Plant growth regulators are known to modify crop growth and development patterns by exerting profound effects on many physiological processes, thereby increasing the productivity of crops. Plant growth promoters may prove beneficial by decreasing flower drop, increasing fruit set, and enhancing partitioning to the sink, whereas growth retardants may prove effective in arresting excessive vegetative growth, thereby increasing the number of capsules and increasing translocation of assimilates to the sink. Day (2000) found that plant growth regulator treatment did not influence sesame’s capsule anatomy, reduce capsule dehiscence, or improve seed retention. Although a number of factors may be responsible for low yield in sesame, soil fertility, particularly the availability of micronutrients, may be a major limiting factor affecting the yield. Sesame productivity is often limited by one or more micronutrients, because in India sesame generally succeeds rice or groundnut in rotation, and these crops are heavy feeders (Balamurugan and Venkatesan 1988; Muthuvel et al. 1985). In this chapter, we examine the effect of plant growth regulators, micronutrients, and salinity on germination, growth attributes, biochemical parameters, yield and yield attributes, and biotechnological aspects of sesame.

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Effect of Plant Growth Regulators and Micronutrients on Germination Plant growth regulators and micronutrients increase sesame germination (Srimathi et al. 2006; Suma et al. 2006). Seed soaked with indole-3-acetic acid (IAA) at 20 ppm for one hour and gibberellic acid (GA) at 10 ppm for four hours enhanced germination, whereas soaking for 16 hours decreased germination (Sahoo et al. 1989). Kyauk et al. (1995) studied the effect of temperature and presoaking on sesame germination and seedling attributes. Seed soaked for 12 hours in 500 mg L-1 GA3 enhanced germination and root shoot ratio of seedlings grown at 15°C. Azospirillum brasilense (Doberenier) is a growth-promoting rhizobacterium. Sukanthi et al. (2001) conducted an experiment with sesame grown in homobrassinolide (a brassinosteroid with growth-promoting activity) and Azospirillum brasilense, alone and in combination. Homobrassinolides alone at 0.5 ppm and 1.0 ppm gave 62% and 72% germination, respectively, whereas Azospirillum brasilense treatment resulted in 81% and 89% germination. Therefore, biological fertilizers such as Azospirillum brasilense may be useful in enhancing growth-promoting activity of hormones. An experiment conducted with two sesame varieties, ‘CO1’ and ‘Annamalai1,’ and four treatments, namely T1–control (seed without any treatment), T2–water soaking, T3–IAA at 100 ppm, and T4 –GA3 at 100 ppm, revealed that all treatments increased germination percentage, shoot length, root length, dry matter production, and vigor index (germination percentage times dry matter production) compared to the control. ‘Annamalai1’ performed better than ‘CO1’ under moisture stress (Prakash et al. 1995). This study reveals the suitability of Annamalai1 for cultivation under limited moisture conditions.

Effect of Plant Growth Regulators and Micronutrients on Growth Attributes Plant growth regulators and micronutrients influence growth parameters—plant height, number of branches, number of leaves, and leaf area—which in turn increase dry matter production and harvest index, resulting in increased seed yield. Application of naphthalene acetic acid (NAA) increased plant height, number of branches, and number of leaves, whereas CycocelTM (CCC) application reduced plant height and increased number of branches and leaves. NAA application also increased leaf area, leaf area index, crop growth rate, net assimilation rate, specific leaf weight, shoot root ratio, dry matter production, and harvest index, whereas CCC application decreased leaf area, leaf area index, shoot root ratio and increased crop growth rate, net assimilation rate, specific leaf weight, and harvest index (Ravichandran 1989). Li et al. (1987) obtained a similar increase in leaf area index and dry matter with mepiquat chloride and CCC application. Foliar sprays of 20 ppm NAA and IAA dispensed 25 and 45 days after sowing significantly increased plant height, leaf area index, and dry matter production (Sahoo et al. 1989). These studies confirm growth-promoting activity of NAA and IAA, and growth-retarding activity of CCC. Application of CCC at 200 mg L-1 increased shoot-root ratio, leaf protein content, and seed yield. The highest seed yield was obtained with irrigation supplied at branching, peak flowering, and capsule development stages, and with CCC treatment at 200 mg L-1 (Garai and Dalta 2002). Application of mepiquat chloride at 125 ppm at 0+1 leaf stage, at 0+2 leaf stage, and at both 0+1 and 0+2 leaf stages decreased plant height and the number of primary branches per plant, and increased the number of secondary and tertiary branches per plant, capsules per plant, seeds per capsule, 1000-seed weight, and test weight (Imayavaramban et al. 2004). Application of Ethrel at the rates of 50, 100, 150, and 200 ppm increased plant height, number of branches, number of capsules per plant, 1000seed weight, and seed yield (Kathiresan et al. 1997). Prakash (1998) conducted field experiments to study the influence of four plant growth regulators and three micronutrients in sesame. The treatments included 1) CytozymeTM, 2) Planofix®TM,

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Table 14.1 Details of Plant Growth Regulators Plant Growth Regulator Cytozyme™

Planofix®™ Chamatkar™ Cycocel™

Composition A plant growth regulator of biologically derived protein hydrolysate containing plant growth promoting substances, enzyme precursors, and activated micronutrients. A plant hormone spray containing alpha naphthyl acetic acid (4.5%. a. i.) Contains mepiquat chloride, 5.0 % solution Contains 11.8 % chlormequat, (2-chloroethyl) trimethyl ammonium chloride

Manufacturer MAC Industries Ltd., Chennai

Bhopal Pesticides Pvt. Ltd., Bhopal Gharda Chemicals Ltd., Mumbai BASF, Mumbai

3) ChamatkarTM, 4) Cycocel, and three micronutrients: zinc sulfate (ZnSO4), manganese sulfate (MnSO4) and borax (Na2B4O7.10H2O), along with a control. The details of plant growth regulators are summarized in Table  14.1, and the responses of sesame to Cytozyme, Planofix, Chamatkar, Cycocel, and micronutrients are discussed below. Prakash (1998) observed that of the plant growth regulators used, Planofix and to a lesser degree Cytozyme resulted in taller plants, whereas Chamatkar and Cycocel reduced height to levels below that of the control (Table 14.2). Increased plant height with Planofix and Cytozyme could be due to increased activity of roots and uptake of more nutrients. Decreased plant height with Chamatkar and Cycocel may be due to their inhibitory effect on GA, resulting in dwarfism. Ravichandran (1999) reported similar results in sesame: increased plant height with NAA application and decreased plant height with Cycocel application. Exogenous application of Chamatkar produced more branches and leaves than Cycocel, Planofix, and Cytozyme. This might be the result of its negative influence on plant height. The nutrients might be being diverted to produce more branches and leaves. Among micronutrients, ZnSO4 induced greater plant height, followed by MnSO4 and B. Their availability might have helped the development of side shoots from axillary buds, leading to increased number of branches and leaves. Balamurugan and Venkatesan (1988) reported a similar observation. The effect of micronutrients on growth parameters is summarized in Table 14.3. Leaf area is considered to be one of the fundamental determinants of photosynthetic rate in crop plants. Usually, high-yielding crop varieties have a higher leaf area than low-yielding varieties. Prakash (1998) also observed that Planofix stimulated leaf area, followed by Cytozyme and micronutrients Zn, Mn, and B, whereas Chamatkar and Cycocel induced lower values than the control. Ravichandran (1989) also reported an increase in leaf area with Planofix and a decrease in leaf area with Cycocel application.

Effect of Plant Growth Regulators and Micronutrients on Biochemical Parameters Biochemical parameters such as leaf chlorophyll content, soluble protein, and nitrate reductase activity play a vital role in influencing plant metabolism and thereby enhance growth and development of crop plants. Chlorophyll, the pigment responsible for photosynthetic processes, is one of the basic determinants of photosynthetic efficiency. Prakash (1998) observed that treatment with Chamatkar and Cycocel resulted in higher chlorophyll content, with decreasing stimulation by Planofix and Cytozyme (Table 14.2). Enhanced levels of chlorophyll content with plant growth regulator application may be attributed to an increased rate of chlorophyll synthesis or inhibition of the enzyme chlorophyllase, which is responsible for chlorophyll breakdown. Ravichandran (1989)

97.4 101.6 102.5 89.2 90.7 99.5 98.8 98.5 10.1

5.3 7.9 8.1 9.2 9 7.1 7.4 7.3 2.11

Numberof Branches

114.1 121.5 123.1 130.4 128.3 119.2 117.7 117.6 20.3

Number of Leaves 1119.7 1161.2 1179.6 1099.8 1109.3 1157.4 1149.4 1134.7 133.3

Leaf Area (cm2 plant–1) 1.174 1.266 1.277 1.308 1.299 1.224 1.209 1.193 0.148

Total Chlorophyll Content (mg g–1fr.wt) 9.23 11.93 12.54 11.22 11.03 10.39 10.08 9.93 0.31

Soluble Protein (mg g–1fr.wt) 6.34 7.18 7.36 6.98 6.88 6.72 6.55 6.5 0.21

Nitrate Reductase Activity (mg NO2 g–1 m–1) 62.93 77.65 83.3 80.73 76 73.27 70.23 66.93 43.25

No. of Capsules per Plant

36.3 38.6 39.1 38.8 38.1 37.5 37.2 37.9 1.97

No. of Seeds per Capsule

2.91 2.99 3.02 3 2.97 2.96 2.94 2.93 0.16

1000Seed Weight (g)

4.86 6.04 6.51 6.32 5.9 5.68 5.45 5.16 0.3

Seed Yield per Plant (g)

Note: T0 – Water spray; T1 – Cytozyme (500 ppm); T2 – Planofix (30 ppm); T3 – Chamatkar (125 ppm); T4 – Cycocel (1000 ppm); T5 – ZnSO4 (0.5%); T6 – MnSO4 (0.3%); and T7 – Borax (0.1%).

T0 T1 T2 T3 T4 T5 T6 T7 C.D (5%)

Treatment

Plant Height (cm plant–1)

Table 14.2 Effect of Plant Growth Regulators and Micronutrients on Growth, Biochemical, and Yield Parameters

248 Sesame: The Genus Sesamum

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Table 14.3 Effect of Micronutrients on Growth and Yield Parameters Manganese

Zinc

Iron

Increased shoot, root weight and dry matter production, number of capsules, yield and oil content. Increased total nitrogen and protein content. Increased leaf area index and dry matter production. Increased number of capsules Increased number of capsules and seed yield. Increased plant height, number of branches, leaves, leaf area index, dry matter production and yield. Enhanced plant height, number of branches, leaves, capsules and seed yield. Increased number of capsules and seed yield. Enhanced plant height, number of branches, leaf area index, dry matter production, leaf chlorophyll and soluble protein, yield and yield attributes. Increased seed yield, oil content.

Veerannah (1970) Veerannah and Rao (1974) Vadivel (1980) Balamurugan (1982) Balamurugan and Venkatesan (1988) Tiwari et al. (1995) Shanker et al. (1999) Jagannathan et al. (1990) Balasubramanian et al. (1993) Prakash (1998) Thiruppathi (2000) Muralidharudu and Mev Singh (1990)

was also of the opinion that increased chlorophyll induced with growth promoters increases the rate of synthesis of chlorophyll rather than the rate of degradation of chlorophyll. Similar observations of increased chlorophyll content with Cycocel application were reported by Bashist (1990) and Pain and Nayek (1981). Soluble protein is a measure of RUBP carboxylase activity (Ku et al. 1979), which can serve as an index for photosynthetic efficiency of crop plants. Similarly, nitrate reductase activity reduces NO3 to N, which in turn helps increase yield. All plant growth regulators and micronutrients examined increased soluble protein content and nitrate reductase activity (Prakash 1998). Ravichandran (1989) previously reported a similar observation of increased soluble protein and nitrate reductase activity with Planofix application.

Effect of Plant Growth Regulators and Micronutrients on Yield and Yield Attributes Sesame seed yield can be enhanced by increasing the number of branches and number of capsules per plant (Ghosh and Sen 1980). Application of growth hormones increased the number of capsules per plant, number of seeds per capsule, and seed yield (Sontakey et al. 1991). NAA application increased the number of capsules, 1000-seed weight, number of seeds per capsule, and seed yield. CCC application increased the number of capsules and 1000-seed weight (Pain and Nayek 1981) and decreased oil content (Li et al. 1987). An increased number of capsules and oil content was also reported by Li et al. (1987) with mepiquat chloride application. Spraying 20 ppm NAA increased the number of capsules per plant, number of seeds per capsule, and seed and oil yield (Garai et al. 1990). Increased seed yield of 16.7% was recorded with NAA at 20 ppm at flowering stage (Tripathy et al. 1996). A study conducted with the objective of maximizing productivity in sesame tested NAA at 50 ppm, Ethrel at 100 ppm, and mepiquat chloride at 125 ppm. Plants treated with Ethrel had significantly higher yields with more pods per plant and higher harvest index (Rajendran et al. 2000). Application of NAA at 30 ppm applied 35 and 50 days after sowing increased yield by 26% and enhanced flower production 7.7% and flower retention 15.5% over the control (Meyyappan and Vaiyapuri 2001). Application of NAA at 20 ppm increased total dry matter by 21.4%, reduced flower drop to 54.0%, and increased seed yield 40% over controls (Prakasa Rao 2002).

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Two growth regulators (CCC at 1000 ppm, Ethrel at 200 ppm) were studied during two seasons, summer and kharif. Yield during summer was higher than that during kharif, and application of Ethrel at 200 ppm at 25 days after sowing produced 1282 kg ha-1 (Kathiresan et al. 2001). Prakash (1998) observed that Planofix treatment results in more capsules. Chamatkar, Cytozyme, and Cycocel treatment induced fewer (Table 14.2). Planofix also increased the number of seeds per capsule and 1000-seed weight better than did Chamatkar, Cytozyme, and Cycocel. Treatment with Planofix and Cytozyme increased capsule number by reducing flower drop. This may be attributed to the presence of auxin in Planofix and growth promoter enhanced with nutrients in Cytozyme. The increased number of capsules on plants treated with Chamatkar and Cycocel was due to growth retardant suppressing vegetative growth while promoting initiation of flower buds, leading to more capsules. Li et al. (1987) reported increased number of capsules with mepiquat chloride treatment, and Pain and Nayek (1981) with CCC application. Ravichandran (1989) reported increased number of seeds per capsule and 1000-seed weight with NAA and Cycocel application. Prakash (1998) reported increased number of capsules per plant, with more capsules resulting from ZnSO4 than from MnSO4 and B. An increase in capsule number was reported by Balamurugan (1982) and Balamurugan and Venkatesan (1988). Mala et al. (2001) conducted field experiments with two plant growth regulators (GA and NAA) and three micronutrients (ZnSO4, MnSO4, and FeSO4) and revealed the combined effect of seed soaking with GA at 20 ppm for four hours and foliar spray of 0.5% MnSO4 twice (at 25 and 40 days) after sowing significantly increased fruit set to 74%, whereas control plants set 47.5%. Field experiments conducted to study the effect of three growth regulators—NAA (40 ppm), salicylic acid (100 ppm), and brassinolides (0.3 ppm)—and sulfur levels; their split application on yield and quality revealed that application of salicylic acid (100 ppm) and 40 kg sulfur in two splits recorded a maximum yield of 1395 kg ha-1. Growth regulators and sulfur application also influence protein content and oil yield (Thangaraj et al. 2005). Prakash (1998) recorded seed yields ranging from 520 to 590 kg ha-1 with foliar application of plant growth regulators, and 447 to 492 kg ha-1 with foliar application of micronutrients, whereas control (unsprayed) plants yielded only 413 kg ha-1. Ravichandran (1989) and Meyyappan and Vaiyapuri (2001) made similar observations with growth regulators.

Effect of Plant Growth Regulators and Micronutrients on Sesame Tissue Culture Plant growth regulators and micronutrients play a fundamental role in tissue culture growth. Cytokinin (in the form of benzyl amino purine or 2ip) induced axillary bud proliferation in sesame (George et al. 1987; Jeyamary and Jayabalan 1995). Benzyl amino purine (mg L-1) with NAA (0.5 mg L-1) produced the maximum number of multiple shoot buds in sesame (Gangopadhyay et al. 1998). Simma et al. (2001) studied the nutritional, hormonal, and environmental factors affecting callus induction and proliferation with somatic calli from seeds, hypocotyls, and cotyledons of sesame. They found that the best medium for callus initiation, proliferation, and maintenance was Murashige-Skoog containing 1.0 mg of 2,4-D and 0.1 mg L-1 of kinetin. Shoot tip organogenesis was evaluated in sesame cotyledon explants grown in Murashige-Skoog medium supplemented with 0.5–10 mg L-1 6-benzyl amino purine, 0.5–2.5 mg L-1 kinetin, and 0.5–5.0 mg L-1 adenine di-sulfate. Initiation of multiple shoots started from the 10th day. After eight weeks, a higher frequency of multiple shoots was observed (Baskaran and Jayabalan 2003).

Response of Sesame to Salinity and Modulating Impact of Growth Regulators Sesame is susceptible to alkali, and yields begin to decline at ESP 15 (Yousif et al. 1972). Presowing seed treatment with 20% coconut water improves establishment under salt stress condition

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(Jagadeesan et al. 2001). Sesame cultivar CO1 soaked in 1.5% solution of SakthiminTM, a micronutrient mixture, showed enhanced germination percentage, root length, shoot length, dry matter production, and vigor index under induced saline (50 mM and 100 mM) conditions (Saravanan et al. 2001). Triadimefon, a triazole derivative, protects plants from abiotic stresses such as salinity, drought, and temperature extremes (Asare-Boamah et al. 1986; Muthukumarasamy and Panneerselvam 1997). Sunil Kumar et al. (2001) studied the effect of triadimefon on growth and metabolism of salt-stressed sesame seedlings, and observed that sodium chloride stress (50 mM) decreased germination percentage, shoot length, and root length, and increased α-amylase and ATPase activity, whereas saline-treated seedlings with triadimefon (1.0 µ mL-1) showed increased germination percentage, shoot length, and root length, and decreased amylase and ATPase activities. Priming with NaCl (0.5 M and 1.0 M) increased germination percentage and vigor index under saline conditions (Prakash et al. 1998). Prasanth et al. (2001) reported that seed treatment with GA3 at 100 ppm increased germination percentage, shoot length, root length, dry matter production, and vigor index under normal and induced stress in 100 mM NaCl. According to Yousif et al. (1972), the sesame cultivar ‘Margo’ can tolerate moderately saline soils. Sesame can be grown better in vermiculite wetted with solution of mixture of salts rather than a single salt (Nassery et al. 1979). Defoliation experiments revealed that phloem transport did not limit leaf growth of salt-stressed plants (Nassery et al. 1978). Studies on mean performance of the genotypes revealed that genotypes IVTS-2006-16, KKS-5, and IS-366 gave higher yield under saline-stress conditions than normal conditions (Thirugnana Kumar 2002). Salt tolerance of four sesame cultivars, ‘Faisalbad Black,’ ‘Pb-90-93,’ ‘Pb-T-90,’ and ‘T-S-3,’ was assessed at germination and later growth stages (Mahmood et al. 2003). A considerable degree of variability was found between cultivars for quantitative and qualitative traits. In general, the responses of ‘Pb-T-90’ and ‘Pb-90-93’ were intermediate while ‘T-S-3’ appeared to be more susceptible to salinity for yield attributes. ‘Faisalbad Black’ sustained growth, yield, and qualitative traits under varying salt regimes and revealed a consistent degree of salt tolerance. The study affirms that individual seedlings that withstand stress at early growth stages could produce tolerant adult plants. Sesame is more sensitive to a single salt than to a mixture of salts. Cultivar differences exist in their sensitivity to salinity during germination and growth. Gehlot et al. (2005) evaluated recently released cultivars for their relative tolerance to sodium chloride. Salinity-induced alterations in electrophoretic patterns of proteins and other metabolites were recorded in seeds grown in the presence of different concentrations of sodium chloride (0, 30, 50, and 70 mM), and it was found that the salt-sensitive cultivar ‘RT 125’ accumulated higher concentrations of malondialdehyde (MDA) and proline, whereas salt-tolerant cultivars ‘RT 54’, ‘RT 46’, and ‘RT 127’ had higher activities of superoxide dismutase (SOD) and low MDA content compared with ‘RT 125.’ They reported that high activity of SOD may contribute to better salinity adaptations in ‘RT 127,’ which is also supported by low MDA content, suggesting that ‘RT 127’ has higher salt tolerance than other cultivars studied.

Conclusions and prospects The major constraints in sesame cultivation are excessive vegetative growth, flower drop, and poor seed fill, conditions that are associated with nutritional and hormonal imbalance. Insufficient study has been made of nutrients and plant growth regulators to enhance yield. Attention should be given to developing a plant growth regulator that will arrest excessive vegetative growth, but enhance assimilate translocation to the sink at later stages of crop maturity. It is essential to remember that most experiments conducted with micronutrients are location-specific. Insufficient attention has been given to increasing sesame oil content. Though some specific information on responses of particular cultivars of sesame to environment and effect of treatments are available, much more research will be needed to enable scientists to understand the response of sesame to environment and its management.

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Few scientists work on sesame improvement with plant growth regulators and micronutrients, compared to other oilseed crops such as soybean and groundnut. More linkage and interaction between sesame scientists is essential.

Acknowledgments The author thanks B. Sunil Kumar, G. Sathiyanarayanan, and S. Suganthi for their help in manuscript preparation, and Dorothea Bedigian for extensive rewriting.

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Genetics in Relation 15 Seed to Yield in Sesame S. Thirugnana Kumar Contents Introduction..................................................................................................................................... 255 Studies on Sesame Seed Genetics................................................................................................... 255 Correlation Studies Regarding Seed Size and Yield in Sesame...................................................... 256 Studies on Genetic Divergence in Sesame...................................................................................... 257 Studies on Stability Analysis in Sesame......................................................................................... 257 Studies on Combining Ability......................................................................................................... 258 Heterosis in Sesame........................................................................................................................ 258 Studies on Gene Action Unique to Sesame..................................................................................... 259 Studies on Maternal Effects and Cytoplasmic Influence................................................................260 Conclusions..................................................................................................................................... 261 Acknowledgments........................................................................................................................... 261 References....................................................................................................................................... 261

Introduction Sesame (Sesamum indicum L.) is an important, traditional oilseed crop grown in tropical and temperate zones. In India it is grown on an area of 1.85 million hectares (ha), and India’s production is about 628,000 metric tons (T) (FAOstat 2006). There is an urgent need to increase oilseed production to meet the needs of an increasing Indian population, to assure food and nutritional security (Hegde 1998; Swaminathan 1989). It is projected that India’s total edible oil consumption will increase 5.5% to 6.0% per annum. Assuming India’s population to be 1300 million and per capita oil consumption 16 kg per annum by 2020, the edible oil requirement will be 20.8 million metric tons (T), equal to 60 million T oilseeds (Lavanya 2005). Groundnut, rapeseed-mustard, soybean, and sesame rank highest, in that order, in India’s domestic edible oilseed production. The dramatic transformation of the Indian oilseed economy from net importer status in the 1980s to self-sufficient and net exporter during the early 1990s was heralded a “yellow revolution” (Kiresur 1999). However, India became a net importer of edible oils again in the late 1990s. Average productivity in India is 332 kg per ha, in contrast to the potential yield of 1000 kg per ha (Ganesan 2005) under optimal fertility and moisture. Therefore, there is an urgent need to augment sesame productivity through the integration of wide adaptability and high yield potential. Information on the genetics of seed size, seed yield, and their components is a prerequisite for selecting suitable parents for a successful breeding program. Evaluation of sesame genotypes should facilitate their use as gene donors.

Studies on Sesame Seed Genetics In many crop species, seed size increases in domestication. It is not only an important primary component of grain yield but also a valuable parameter for seedling establishment and crop 255

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growth. During the past four to five decades, seed size studies examined physiological parameters. Observations of a positive relationship between size and seed yield are seen in groundnut (Borate et al. 1993) and soybean (Saka et al. 1996). Osman Khidir and El-Gizouli Osman (1970) suggested that seed size is one of the best criteria for selection of yield improvement in sesame. Saga and Bhargawa (1980) recommended higher number of seeds per plant. Gangrade et al. (1973), Lee et al. (1986), and Mosjidis and Yermanos (1985) examined variation in oil and protein content. They opined that selection for oil and protein content is possible. Thirugnana Kumar (1991) claimed that one cannot select, in early generations, for capsule volume, number of seeds per capsule, seed length, seed breadth, 1000-seed volume, 1000-seed weight, seed density, and oil content because these are controlled by non-fixable gene effects.

Correlation Studies Regarding Seed Size and Yield in Sesame Many complex processes influence seed yield. Most component characters are under the control of genes, which environment influences greatly (Thirugnana Kumar 1991). One cannot separate the direct contribution of each component to seed yield and the indirect effect it has through its association with other components by mere correlation studies. Thus, it is necessary for a plant breeder to have information about the direct and indirect effects of these components on yield to identify the key characters for improvement. Sewell Wright (1921) developed the path-coefficient analysis, a technique that is an effective biometrical tool for understanding the direct and indirect effects of component characters on seed yield. It also permits critical examination of specific factors that produce a given correlation. Correlation and path-coefficient analysis assume special importance in deciding the basis for selection of desired characters and the directional focus through which to improve seed yield. Efforts to understand the association between seed yield and its component characters in sesame reveal that seed yield is positively and significantly associated with plant height, number of branches per plant, number of capsules per plant, and 1000-seed weight (Bhele et al. 1987; Krishnadoss and Kadambavanasundaram 1986; Osman Khidir and El-Gizouli Osman 1970; Paramasivam and Prasad 1980; Sikka and Gupta 1947; Thirugnana Kumar 1991). Other studies (El-Gizouli Osman and Osman Khidir 1974; Omar Sheik 1989; Saravanan 1999; Thirugnana Kumar 1991) found the association between days to maturity and seed yield to be positive. Many found correlation of these characters to be both positive and significant. It added a scope for breeding for earliness in sesame without sacrificing yield. Thirugnana Kumar (1991) observed a neutral association between seed yield and capsule volume. He found significant positive association of seed length with seed yield, 1000-seed weight, oil content, and harvest index. The volume of 1000 seeds exhibited a constant negative significant association with seed density and a rarely seen, significant negative association with number of capsules. There is an unusual positive significant association between plant height and weight of 1000 seeds (Thirugnana Kumar 1991). Ibrahim et al. (1983) found that oil content was negatively associated with seed yield to a significant degree, although Thirugnana Kumar (1991) found neutral association between seed yield and oil content. These results indicate that seed yield and oil content are improved simultaneously in the genotypes of the study, because the relationship is genotype-specific. A critical analysis of the direct and indirect effects of the component characters gives additional information showing which specific factors produce a given correlation. Studies of path analysis in sesame indicate that plant height, number of branches, number of capsules, and 1000-seed weight show positive direct effects upon seed yield (Ananda Kumar and Sivasamy 1996; Chandrasekhara and Ramana Reddy 1993; Praveen S. Kumar 2003; Thirugnana Kumar 1991; Tomar et al. 1999). Thirugnana Kumar (1991) found that plant height, number of branches, flowers and capsules, 1000seed weight, seed density, total dry matter production, and harvest index are the major yield components affecting seed yield, as overall their effects were positive and consistent over three seasons. Of these traits, the total dry matter production and the harvest index (harvest index was determined by

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adding the weight of senesced leaves [collected daily], dried stems [during harvest], empty capsules, and seeds) exerted consistent positive direct effects towards seed yield, equal to their genetic correlation coefficients. Moreover, through these traits alone, other positively correlated traits exerted indirect positive effects. Thus, total dry matter production and harvest index assume special importance in the choice of characters in sesame breeding. However, as total dry matter production and harvest index are negatively correlated, selection may be practiced on seed yield.

Studies on Genetic Divergence in Sesame Having genetically diverse parents in hybridization trials often brings success. Crosses between divergent parents usually produce greater heterosis (increased vigor of F1 progeny) than between closely related ones, and show transgressive segregation (progenies exceeding parental limits) (Moll and Stuber 1971). Genetic divergence studies are vital tools for the evaluation of germplasm lines and selection of parents for a breeding program (Arunachalam 1981). The genetic architecture of a population is the result of prolonged natural selection. Populations that occur in diverse environments are frequently immensely diversified genetically. Thus, it is necessary to understand the extent and rates of genetic divergence between diversified forms. Genetic diversity must be sufficient to justify breeding efforts. Genetic diversity may be available both in improved germplasm and in genetically inferior stocks. The availability of statistical tools to quantitatively measure the genetic divergence between two or more populations and the relative contribution of individual characters to the total divergence permit us to trace evolutionary patterns in crops and select the parents for hybridization in crop plants. Among several statistical methods developed for measuring the divergence between populations, multivariate analysis (D2 statistic), developed by Mahalanobis (1936), is a potent tool. It is effective in quantifying the degree of divergence at the genetic level and provides a quantitative measure of the association between geographic and genetic diversity based on generalized distance. Griffing and Lindstorm (1954) observed a parallelism between genetic diversity and geographical distribution in maize. However, absence of such parallelism and presence of forces other than geographical origin are responsible for genetic divergence in sesame, as shown by Bedigian et al. (1986), Dhamu et al. (1983), Rathinaswamy and Jagathesan (1984), Solanki and Gupta (2001), Swain and Dikshit (1997), Trehan et al. (1974), Thangavelu and Rajasekaran (1983), and Thirugnana Kumar (1991). Studies conducted by these workers indicate that geographic diversity does not necessarily imply genetic diversity, because genotypes from different eco-geographic regions formed one group. Likewise, genotypes from the same eco-geographic regions scattered in different clusters. Many workers have reported that days to maturity, plant height, number of capsules per plant, oil content, and 1000-seed weight contribute most towards genetic diversity. Thirugnana Kumar (1991) found that volume of 1000 seeds followed by oil content contributed maximally towards genetic diversity over three seasons.

Studies on Stability Analysis in Sesame Sesame is primarily a rainfed low-input crop; hence, fluctuations in yield levels closely follow changes in the environment and seasons. Many methods of analysis for stability exist; Eberhart and Russel’s (1966) method has been used extensively in crop breeding programs. No stability analysis studies on sesame are reported yet. Farrokhi and Ahamadi (1998), Henry and Daulay (1987), Kandaswamy (1985), Rathinaswamy and Jagathesan (1982), Thirugnana Kumar (1991), and Thirugnana Kumar et al. (2004) found significant genotype × environment or season interaction for seed yield. Thirugnana Kumar (1991) stated that the prediction of performance for the characters days to maturity, plant height at maturity, number of branches, number of flowers, number of capsules, number of seeds per capsule, seed length, seed breadth, 1000-seed weight, 1000-seed volume, seed density, oil content, seed yield, and harvest index was possible, whereas the prediction

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of performance for capsule volume and total dry matter production was not possible. Thirugnana Kumar (1991) concluded that mean productivity, production response (regression of genotypes to seasonal variation), and production stability are relatively independent.

Studies on Combining Ability A parent chosen for hybridization should have high general combining ability (GCA), so that when pooled, the hybrids produce superior recombinants with better yield and other desirable traits. Sprague and Tatum (1942) first proposed the combining ability’s impact on genetic variations. Combining ability consists of general combining ability (GCA) and specific combining ability (SCA). General combining ability is the “average performance of a line in hybrid combinations.” Specific combining ability as defined is “those cases in which certain combinations do relatively better or worse than would be expected on the basis of the average performance of the lines involved.” Sprague and Tatum (1942) attributed the GCA effects to the additive effects of genes and SCA effects upon dominance and epistatic interactions. Lonnquist (1951) stated that lines high in combining ability are high presumably because of a larger proportion of favorable yield genes. High GCA and SCA effects have been reported for days to maturity, plant height at maturity, number of branches, capsule volume, number of seeds per capsule, seed length, seed breadth, 1000-seed weight, 1000seed volume, seed density, oil content, seed yield, total dry matter production, and harvest index (Bhagawan Dora and Kamala 1987; Khorgade et al. 1988; Krishnadoss et al. 1987; Omar Sheikh 1989; Thirugnana Kumar 1991). The combining ability of the parents is a better index for selection of parents for hybridization than their mean performance, but the estimation of combining ability involves hybridization and analysis of data based on a mating design. This involves a lot of time and work. If it is possible to know the relationship between the mean values and GCA effects in sesame, it may help the breeder to choose parents based on the mean values, at least for such characters in which the relationship between combining ability and mean values are established. Alternatively an index may be formulated between mean values and combining ability. This would enable breeders to use different types of variations. Sesame breeders have indicated that reliance on mean performance can determine choice of parents (Krishna Devi et al. 2000a; Saravanan et al. 2000a; Thirugnana Kumar 1991). Parental performance is a good indicator of GCA effects, since ranking of parental genotypes for their GCA effects is similar to the parental performance per se.

Heterosis in Sesame Most approaches to crop improvement in sesame involving selection or hybridization followed by selection have thus far experienced only marginal improvement. Therefore, to boost yield, exploitation of heterosis breeding (the increased performance of F1 progenies over the parents) is gaining importance. It is necessary to reshuffle the genes by crossing and to study the heterotic effects in the F1 generation to enhance the yield potential of hybrids. In plant breeding, three biometric genetic techniques, namely diallele, partial diallele, and line × tester analysis, are common in the selection of parents for hybridization. A diallele cross refers to mating of selected parents in all possible combinations, and the evaluation of a set of diallele crosses is known as diallele analysis. In a partial diallele design, each parent is matched with some, but not all, of the other parents. In the line × tester mating design, the genotypes or cultivars undergoing evaluation are selected from a germplasm collection of genotypes. Some of the selected genotypes are designated males (testers) and others as females (lines). Each male parent is paired with each female parent, but male parents are not crossed with each other, and female parents are not crossed with each other. Each male is paired with the same set of females. Heterosis breeding in sesame began in British India in 1935 (Pal 1945). A high level of heterosis occurred with certain combinations. Even though sesame is predominantly a self-pollinated

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crop, honeybees increase cross pollination (Uzo and Ojiake 1981). Therefore, hybrid seed production is economically feasible. Moreover, the discovery of stable genetic male sterility (Osman and Yermanos 1982) intensified research. Heterosis, representing deviation of F1’s from the mid-parent, better parental stock and standard check varieties, was computed in diallele and line × tester mating designs. Some of the studies related to generation mean analysis (generation mean analysis involves six consecutive generations: parents (P1, P2) and their F1, F2 and back crosses (B1, B2); the analysis is based on the mean values over replications) also report the extent of heterosis. Pal (1945) reported the phenomenon of heterobeltiosis (performance of F1 hybrids over the better parent of that cross) for seed yield up to 121.4%. High standard heterosis for seed yield was reported at these escalating rates: 52.28% (Ramanathan 1998); 53.49% (Saravanan et al. 2000a); 102.90% (Shinde et al. 1993); 108.31% (V.K. Singh et al. 1986); 335.64% (Thirugnana Kumar 1991). Karuppaiyan et al. (2000) reported negative standard heterosis up to 24.55% for days to maturity. Mishra and Yadav (1994) reported a maximum standard heterosis of 38.46% for number of seeds per capsule. Thirugnana Kumar (1991) reported the maximum standard heterosis, 308.93%, for number of capsules per plant, 21.03% for seed length, 48.79% for seed breadth, 128.09% for 1000-seed weight, 454.56% for 1000-seed volume, 58.78% for seed density, and 13.46% for oil content. Given that emasculation is easy, and pollen abundant, with hand pollination it is possible to obtain a large number of seeds per capsule. Exploitation of heterosis is a feasible proposition that needs to be probed further using more unique parents, particularly non-shattering types. In most of these studies, there exists a good relationship between mean performance and heterosis. Thus, performance per se appears to be the ideal indicator for heterosis.

Studies on Gene Action Unique to Sesame A successful crop-breeding program depends on the proper choice of the best parents for hybridization and an ideal selection adopted in an early generation. However, the selection of parents for a hybridization program is relatively tough in the case of complex traits such as yield and their component characters, because a large number of quantitative genes govern these traits influenced by environment and season. Thus, breeders often meet with difficulty in fixing in advance the desirable parents that will give superior progenies. Knowledge of the nature of gene action on complex quantitative traits of economic importance is necessary for planning and adopting appropriate selection techniques and breeding technology (Simmonds 1979). Assessment of distinctive traits in sesame are typically tested with combining ability variances, with the proportion of genetic parameters in diallele analysis, and with first- and second-degree (mean, variance, and covariance studies) statistics obtainable from the true-breeding inbreds, their first generation crosses, and the various types of segregating progenies (Gamble 1962; Hayman 1958; Mather 1949; Mather and Jinks 1971). Combining ability analysis gives useful information regarding the selection of parents in terms of hybrid performance. This analysis elucidates the nature and magnitude of various types of gene action involved in the expression of quantitative traits. Many workers have reported that the variance for combining ability was highly significant for seed yield and its component traits. Diallele analysis by Backiyarani et al. (1997), Devasena et al. (2001), Dharmalingam and Ramanathan (1993), Imrie (1995), Narkhede and Sudhir Kumar (1991), and Ramesh et al. (1998) showed that GCA variance was more than that of the corresponding SCA variance for seed yield and its component characters. Padmavathi et al. (1994) obtained similar results through line × tester analysis. On the other hand, the diallele analyses of Jayalakshmi et al. (2000), Kavitha et al. (1999), Krishnaiah et al. (2003), Mcharo et al. (1995), and Saravanan et al. (2000a) indicate the importance of SCA variance over the corresponding GCA variance for seed yield and its component characters. The line × tester analysis of Ananda Kumar and Sivasamy (1995), Karuppaiyan et al. (2000), Manivannan and Ganesan (2001), Mishra and Yadav (1996), and Thirugnana Kumar (1991) confirm

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the importance of SCA variance over that of its corresponding GCA variance for seed yield and its component traits. The studies on combining ability clearly reveal the importance of both GCA and SCA variances. In fact, the studies of Dikshit and Swain (2001) and Krishna Devi et al. (2002a) confirm the importance of both GCA (fixable genetic variance) and SCA (non-fixable genetic variance) variances in the improvement of seed yield and its component traits through crop breeding. This indicates that there exist considerable additive variances in the material studied for seed yield and its component characters. Recombination breeding can be used for selections to achieve crop improvement. This phenomenon demonstrates a unique advantage of sesame, compared with many other crops. For example, in maize, selection has exhausted additive variances, and today approaches must exploit non-additive variances. Rapid progress in yield and yield components is possible in sesame, since adequate exploitable additive variances (fixable) still exist in this crop. Generation mean and variance analyses tested gene action and effects. The component of means, generally based on the parental, F1, F2, and first back-cross generations, has been estimated for seed yield and its component characters. Mathers’ scales examine non-allelic interactions. Epistatic interactions were observed for location and environments (Godawat and Gupta 1985). Various researchers (Chavan et al. 1981, 1983; Deenamani 1989; Dixit 1976; Thirugnana Kumar 1991) evaluated approximately 70 cross-combinations for seed yield and its component characters. Many workers found that epistasis is prevalent. Thus, it is apparent that both additive and dominance variances, in addition to epistatic variances, control seed yield, seed size, and their component characters. The magnitude of the variances indicates that the epistatic variances are higher than the additive variances, although this does not preclude the existence of additive variances. Modification of selection methods of various traits is required to mitigate the masking effects of dominance and epistatic variances before selection is successful. Therefore, selection must be postponed until the F6 or F8 generation, when the additive variance get unmasked through the setting in of homozygosity (identical alleles) for most of the genes governing the traits of interest.

Studies on Maternal Effects and Cytoplasmic Influence The contributions of parents to their offspring (Kolreuter 1765 [cited in Roberts (1929)] and Mendel 1865) is usually studied by comparing the F1 hybrids from reciprocal crosses (Cockerham and Weirs 1977) or the F2 population derived from the reciprocal F1’s. Reciprocal F1 populations have confounded maternal and cytoplasmic effects, while a comparison of reciprocal F2 populations provides unequivocal information on cytoplasmic effects. This can be achieved by comparing reciprocal back-crosses (Mosjidis and Yermanos 1984), too. About two-thirds of all plant genera investigated show maternal inheritance of cytoplasmic traits (Tilney-Bassett 1975). Studies on reciprocal differences in sesame have been reported by Mosjidis and Yermanos (1984), Murthy and Hasim (1973), Pal (1945), and Thirugnana Kumar (1991). Thirugnana Kumar (1991) evaluated 1168 sesame cultivars for 1000-seed weight from lines grown in a uniform nursery. Cultivars were split into three seed-size classes, large, medium, and small, based on 1000-seed weight. These were defined as follows: large: > mean + 1 SD = > 3.21 g; medium: in the interval mean ± 1 SD = 2.53 to 3.21 g; small: < mean – 1 SD = < 2.53 g. Out of the 1168 genotypes evaluated, 207 genotypes (39 large-, 121 medium-, and 47 small-seeded selections) were grown. The number of genotypes in each seed-size class was delineated by availability of sufficient seeds and convenience. Seeds were harvested from 207 genotypes, and 1000-seed weight was measured. Three seed-size classes were designated: large: > mean + 1 SD = > 3.19 g; medium: in the interval mean ± 1 SD = 2.57 to 3.19 g; and small: < mean –1 SD = < 2.57 g. Those selections that maintained their respective classes in two consecutive evaluations were preserved. Six crosses were made: three direct and three reciprocal, using three genotypes representing each of the three seed size classes. The three genotypes selected were S.00028 (large seed, 4.23 g), S.0327 (medium seed, 2.56 g) and Ac. No. 672.3.130.12 (small seed, 1.40 g). Thirugnana Kumar produced selfed parents, first generation hybrids (F1’s), second generation hybrids (F2’s) and direct

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and reciprocal back cross progenies (B1’s and B2’s). All six families were studied for 16 quantitative characters: days to maturity, plant height at maturity, number of branches, number of flowers, number of capsules, volume of capsules, number of seeds per capsule, length of seeds, breadth of seeds, 1000-seed weight, 1000-seed volume, density of seeds, oil content, seed yield, total dry matter production, and harvest index. Thirugnana Kumar compared the F1’s, F2’s, B1’s, and B2’s of direct and reciprocal cross combinations and found that the cytoplasm of the large-seeded parent S.00028 differed from the cytoplasm of the medium-seeded parent S.0327 with respect to 14 characters. Similarly, the cytoplasm of the large-seeded parent, S.00028, differed from the cytoplasm of small-seeded parent, Ac. No. 672.3, 130.12, for 12 characters. The cytoplasm of the medium-seeded parent (S.0327) differed from the cytoplasm of the small-seeded parent, Ac. No. 672.3.130.12, for 12 characters. Thirugnana Kumar also observed maternal effects in these parents.

Conclusions Most of the studies reported here reveal the preponderance of non-additive and non-fixable gene effects in sesame. Hence, further improvement of seed size and seed yield by simple pedigree selection (commonly followed) or modified pedigree selection may not be possible. Therefore, seed size and yield improvement can increase by delaying selection to later generations, when dominance and epistatic gene actions disappear, and breeders can resort to inter-mating the segregants followed by repeated selection. In the presence of fixable and non-fixable gene effects along with cytoplasmic influences, the best recurrent scheme to develop hybrids will be an inter-population improvement program. Such a study must allow continuity improvement and variety development. Many scientists after Edgar Anderson (1939), including Al-Jibouri et al. (1958), Delogu et al. (1988), Frey (1984), Gallais (1988a, 1988b), Hallauer (1981, 1986), Jensen (1970), and Ramage (1981), have recommended recurrent selection as a basic breeding approach in autogamous (self-fertilized) crops. On the other hand, the practical utility of recurrent selection in yield improvement of sesame remains to be tested.

Acknowledgments The author thanks Tamil Nadu Agricultural University, Coimbatore, and the International Development Research Centre (IDRC), Canada, for an award as Senior Research Fellow in its sesame improvement program in India, 1987–1990. He is grateful to Annamalai University for permission to devote time to complete this article, and thanks Dorothea Bedigian for generous editorial help.

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Shinde, Y.M., N.P. Deshmukh and P.L. Bhadhe. 1993. Combining ability and heterosis for yield and its components in sesame. Journal of Oilseeds Research 10: 46–55. Sikka, S.K. and N.D. Gupta. 1947. Inheritance studies in Sesamum indicum L. Indian Journal of Genetics and Plant Breeding 7: 35–42. Simmonds, N.W. 1979. Principles of Crop Improvement. Longman Inc., New York. Singh, H.C., V.P. Nagaiah and S.N. Singh. 2000. Genetic variability for drymatter production in sesame (Sesamum indicum L.). Annales of Agricultural Research 21: 323–327. Singh, P.K., R.K. Dixit and R.K. Yadav. 1997. Estimates of genetic parameters, characters association and path analysis in sesame. Crop Research 13: 115–119. Singh, V.K., H.G. Singh and Y.S. Chauhan. 1986. Heterosis in sesame. Farm Science Journal 1: 65–69. Solanki, Z.S. and D. Gupta. 2001. Variability and genetic divergence studies in sesame (Sesamum indicum L.). Sesame and Safflower Newsletter 16: 28–31. Sprague, G.F. 1966. Quantitative genetics in plant breeding. In K.J. Frey, ed., Plant Breeding. Iowa State University, Ames, Iowa. Sprague, G.F. and L.A. Tatum. 1942. General vs specific combining ability in single cross of corn. Journal of American Society of Agronomy 34: 923–932. Sverup-John, U.G. Nair and S. John. 1993. Genetic variability, heritability and genetic advance in sesame. Journal of Tropical Agriculture 31: 143–146. Swain, D. and U.N. Dikshit. 1997. Genetic divergence in rabi sesame (Sesamum indicum L.). Indian Journal of Genetics and Plant Breeding 57: 296–300. Swaminathan, M.S. 1989. Role of rice in global food security. Oryza 26: 1–26. Thangavelu, M.S. and S. Rajasekaran. 1983. Correlation and path coefficient analysis in Sesamum. Madras Agricultural Journal 70: 109–113. Thangavelu, M.S., S.C.S. Sridharan, V. Muralidharan and M. Suresh. 1985. Sesame breeding in the southern states of India and methods of evaluating breeding materials. In A. Omran, ed., Oil Crops: Sesame and Safflower, IDRC – MR 105e. 28–43. Ottawa. Thirugnana Kumar, S. 1991. Seed genetics in relation to yield in sesame (Sesamum indicum L.). Ph.D. Thesis, Tamil Nadu Agricultural University, Coimbatore, India. Thirugnana Kumar, S., A. Anandan and Praveen S. Kumar. 2004. Stability of sesame (Sesamum indicum L.) varieties under different population densities. Crop Improvement 31: 103–106. Tilney-Bassett, R.A.E. 1975. Genetics of variegated plants. In C.W. Birky, P.S. Perlman and T. J. Byers, eds., Genetics and Biogenesis of Mitochondria and Chloroplasts. 268–308. Ohio State Univ. Press, Columbus, Ohio. Tomar, H.S., G.K. Shrivastava, O.P. Tiwari and R.S. Tripathi. 1999. Correlation and path coefficient analysis in summer sesame. Journal of Oilseeds Research 16: 169–170. Trehan, K.B., A.V. Rao, S.K. Metha, H. Chand, H.N. Sharma and S.K. Baijal. 1974. Genetic divergence in sesame. Indian Journal of Agricultural Sciences 44: 208–212. Uzo, J.O. and G.U. Ojiake. 1981. Breeding and selection method for sesame and the basis of assessment of major Nigerian sesame strains. F1 hybrids and segregating generations. FAO Plant Production and Protection Paper 29: 90–96. Weiss, E.A. 1983. Sesame. Pages 282–340 In Oil Seed Crops. Longman, London, New York. Wright, S. 1921. Correlation and Causation. Journal of Agricultural Research 20: 557–585.

Diseases and 16 Sesame Their Management P. Narayanasamy Contents Introduction..................................................................................................................................... 267 Disease Distribution and Economic Importance of the Diseases................................................... 268 Fungal Diseases.......................................................................................................................... 268 Bacterial Diseases...................................................................................................................... 269 Phytoplasma Disease.................................................................................................................. 269 Viral Diseases............................................................................................................................. 269 Detection of Microbial Pathogens and Disease Diagnosis............................................................. 269 Detection of Fungal and Bacterial Pathogens............................................................................ 270 Detection of Phytoplasma and Viral Pathogens......................................................................... 270 Pathogenesis.................................................................................................................................... 271 Epidemiology.................................................................................................................................. 272 Effect of Seed Infection............................................................................................................. 272 Effect of Sowing Dates.............................................................................................................. 272 Weather Factors.......................................................................................................................... 273 Sources of Infection................................................................................................................... 273 Disease Management Strategies..................................................................................................... 274 Agricultural Practices................................................................................................................. 274 Physical Methods....................................................................................................................... 274 Biological Control...................................................................................................................... 275 Improving Host Resistance to Diseases.......................................................................................... 275 Breeding for Disease Resistance................................................................................................ 275 Biotechnological Approaches.................................................................................................... 276 Application of Chemicals............................................................................................................... 276 Fungicides.................................................................................................................................. 277 Natural and Synthetic Compounds............................................................................................ 277 References....................................................................................................................................... 277

Introduction Various microbial pathogens—fungi, bacteria, phytoplasma, and viruses—can infect sesame (Sesamum indicum L.). The extent of losses caused by them varies depending on the level of susceptibility and resistance of cultivars, the virulence of the pathogens, and environmental factors influencing the development of the diseases. The distribution, economic importance, symptoms of the diseases, the diagnostic methods, and the disease management strategies follow.

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Disease Distribution and Economic Importance of the Diseases Fungal Diseases Fungal pathogens can disseminate by way of seeds, soil, water, and air for short and long distances. Knowledge on the primary mode of dispersal and sources of infection will be very useful in developing effective disease management systems. Alternaria sesami causes seed rot and blight diseases in sesame. The pathogen has a world-wide distribution, inflicting serious losses in many areas, including the Caucasus (Kvashnina 1928), India and other Asian countries (Khati and Pandey 2004; Leppik and Sowel 1964; Sulochana and Balakrishnan 1997), and Kenya (Ojiambo et al. 1998a, 2000a). Alternaria alternata induces blight symptoms of spots in stems and on leaves and has a wide host range (Prasad and Reddy 1997). Species of Alternaria have been reported to occur in many countries, including the United States (Culp and Thomas 1964) and El Salvador (Cano and Lopez 1950). Losses from infection of seeds by A. sesami ranged from 4% to 25% in Kenya. Disease severity was negatively correlated with seed yield, 1000-seed weight, and seeds per capsule. Severe leaf infection by A. sesami affected the seed weight component of yield significantly. The permissible level of seed infection was determined to be less than 2% (Ojiambo et al. 2000a). Occurrence of leaf spot disease caused by Cercospora sesami in severe forms in India resulted in an estimated loss of about 30% (Chowdhury 1945; Prasad and Reddy 1997). Appreciable yield reduction from C. sesami was also noted in Panama, Venezuela, and China (Mazzani 1966; Yu 1940). Wilt and root rot diseases are caused by the soilborne pathogens Fusarium oxysporum f. sp. sesamicola and Macrophomina phaseolina, respectively. They infect root and collar tissues (near the soil level), frequently causing the mortality of infected plants. Both are seedborne, thus capable of being transmitted through infected seeds to other geographical locations. The diseases can be devastating, depending on the level of susceptibility of the cultivars. They may persist in the soil for several years. Attacks by nematodes may predispose plants to wilt disease (Ministry of Agriculture, Peru 1965). Phytophthora parasitica var. sesami produces characteristic water-soaked spots on leaves and stems resulting in blackening of affected tissues in stems especially near the soil level (Gemawat and Prasad 1965). This pathogen also is soilborne. High soil moisture and temperatures are favorable for the rapid spread of the disease (Mazzani 1966). A root rot disease caused by Thielaviopsis basicola induces blackening and decay of the root system. This pathogen is soilborne, and disease intensity increases in heavy, slightly acidic or alkaline soils with high humus contents. Castor, another oilseed, is also a known host for this pathogen (Weiss 1971). Both field and storage fungi colonize sesame, resulting in failure of seed germination and crop stand in the field. It is essential to assess the extent of the seedborne nature of fungal pathogens to develop effective disease management strategies. Several microorganisms are associated with seeds. Some of them may reduce seed germination and emergence of plants in the field. Some are capable of invading different parts of the seeds and plants, causing various diseases. Alternaria alternata, Aspergillus flavus, A. niger, Curvularia lunata, Fusarium oxysporum, and Penicillum chrysogenum reduced the seed germination by 30–61%, and maximum seedling rot (34%) was due to infection by Fusarium oxysporum (Khati and Pandey 2004). The composition of the seed mycoflora may vary depending on the location, cultivar, and storage conditions. Some other fungi, such as Aspergillus flavus, produce toxic compounds known as mycotoxins that have carcinogenic properties, inducing serious ailments in animals and humans consuming contaminated seeds or products (Narayanasamy 2005a). Several airborne fungal pathogens, such as Corynespora casiicola (blight disease), Colletotrichum spp. (anthracnose disease), Oidium spp., and Leveilulla taurica (powdery mildew), affecting several plant parts have been reported to be significant in some countries. The extent of losses from these diseases may vary considerably, depending on the varietal resistance, amount of inoculum produced

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in the season, and age of crop at the time of disease incidence. Powdery mildew pathogens are obligate parasites that require the presence of live host plants for their survival and perpetuation. Hence, the role of collateral hosts is a critical factor for the carry-over of such diseases during the absence of a sesame crop.

Bacterial Diseases The bacterial leaf spot disease caused by Pseudomonas syringae pv. sesami (Pss) occurs in most countries where sesame is grown, accounting for substantial yield reduction (Padwick 1956; Sutic and Dowson 1962). The disease is initiated as angular, darker areas with purple margins that progress along the veins and petioles. The infected areas become necrotic and disintegrate, giving a tattered appearance. The disease is favored by high rainfall and high humidity. Flood irrigation spreads the disease rapidly (Tothill 1952). Two new races of Pss have been recognized (Culp and Thomas 1964). Another bacterial leaf spot disease induced by Xanthomonas campestris pv. sesami (Xcs) was observed in India, Sudan, and China (Ciferr 1955; Das 1997; Schumutterer and Kranz 1965).

Phytoplasma Disease Sesame phyllody disease, earlier considered a viral disease, is caused by a phytoplasma and is one of the most destructive, responsible for losses of up to 99% in certain tracts in India (Narayanasamy et al. 1961). An increase in phyllody disease incidence by 1% may lead to yield loss of 8.4% (Murugesan et al. 1978). Reproductive tissues are transformed into vegetative leaf-like structures, resulting in partial or total sterility of infected plants, depending on the age of plants at the time of infection. The incidence of phyllody disease was reported from Myanmar (Burma) (McGibbon 1924), India (Kashiram 1930; Narayanasamy et al. 1961), Sierra Leone and Tanzania (Deighton 1932), Uganda (Storey 1933), Thailand (Kulthongkham 1948), Sudan and Venezuela (Mazzani and Malaguti 1952), Turkey (Turkmenoglu and Ari 1960), Iran (Mostafavi 1970), Upper Volta and France (Weiss 1971), Israel (Klein 1970), and Korea (Seok et al.1997). A reduction of up to 50% in plant height, internode length, number of leaves, and mean leaf area of sesame resulted in heavy reduction in yield under field conditions (Srinivasulu and Narayanasamy 1990). The composition of leafhopper species populations may influence the incidence of phyllody disease. In Turkey, Circulifer haematoceps could transmit SPP and Spiroplasma citri. The efficiency of the leafhoppers collected in various areas differed considerably. The leafhopper could transmit one or both phytoplasma, depending on the area (Kersting and Baspinar 1997).

Viral Diseases Leaf curl disease transmitted by the whitefly vector Bemisia tabaci was reported from East Africa and Sierra Leone (Deighton 1932) and India (Sahambi 1958). The viral origin of the disease is not yet established. Sesame is susceptible to turnip mosaic virus, watermelon mosaic virus, and tobacco ringspot virus under experimental inoculation conditions (Japan Plant Protection Association1967; McLean 1960). However, natural incidence of these viruses is not yet recorded.

Detection of Microbial Pathogens and Disease Diagnosis Early and rapid detection and precise identification and differentiation of microbial pathogens are essential for understanding the nature of primary and secondary sources of infection and variability in pathogenic potential of strains, races, and biotypes within a morphologic species and other related species. Molecular diagnostic methods are more sensitive and provide reliable results rapidly; hence, they are more frequently employed now (Narayanasamy 2001).

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Detection of Fungal and Bacterial Pathogens It is essential to assess the extent of the seedborne nature of pathogens to develop effective disease management systems. Microbial pathogens in seeds and plants are detected through conventional and molecular methods. Several microorganisms are associated with seeds. The composition of seed microflora may vary depending on the cultivar, storage conditions, and geographic locations. Some other fungi such as Aspergillus flavus produce toxic compounds known as mycotoxins that are carcinogenic in nature and can cause serious ailments in animals and humans consuming contaminated grains, foods and feeds. Seedborne fungi associated with sesame can be isolated by using the standard blotter method, direct plating, or the agar test in appropriate media, and by the growing-on test and seedling symptom test (Narayanasamy 2002). Saprophytes associated with seeds frequently overgrow the pathogenic fungi that are comparatively slow-growing in nature, making their isolation in pure culture difficult. Conventional methods can assess seed mycoflora (Ojiambo et al. 1998a; Raghuvanshi 1995; Sulochana and Balakrishnan 1997). The seedborne bacterial pathogens can also be detected, identified, and differentiated by isolation on selective media, such as King’s medium B, and by performing standard biochemical and physiological tests. However, the higher level of sensitivity and reliability of molecular techniques, in addition to the rapidity of providing results, makes them the preferred methods for the identification and differentiation of seedborne fungal and bacterial pathogens. Immunodiagnostic assays such as the enzyme-linked immunosorbent assay (ELISA), dot immunobinding assay (DIBA), and immunofluorescent assay (IFA) and nucleic acid-based techniques such as dot blot hybridization, random fragment length polymorphism (RFLP) analysis, random amplified polymorphic DNA (RAPD), and polymerase chain reaction (PCR) have been applied to gather information about the pathogens associated with seeds of crop plants. The methods employed for the detection of various species of the genera Alternaria, Cercospora, Fusarium, Macrophomina, Phytophthora, and Rhizoctonia may be adapted for the detection of fungal pathogens infecting sesame (Narayanasamy 2001, 2005).

Detection of Phytoplasma and Viral Pathogens All phytoplasma pathogens (except Spiroplasma citri) and the entire group of viral pathogens require live plant hosts. All attempts to bring them into pure (auxenic) cultures in cell-free media have been unsuccessful. Biological methods such as transmission of the phytoplasma or virus by employing grafting or using insect vectors to a range of plant species/cultivars that produce diagnostic symptoms and physical properties—in the case of viruses such methods as dilution-end point (DEP), longevity in vitro (LIV), and thermal inactivation point (TIP)—in addition to host range, have been used to identify and differentiate viruses. But these methods require large glasshouse space and a long time to yield results that are, however, inconclusive and subject to variations (Narayanasamy and Sabitha Doraiswamy 2003). Different leafhopper species may be involved in the transmission of the phytoplasma in different geographical locations. Orosius albicinctus is the vector of sesame phyllody phytoplasma (SPP) in India, and Circulifer hematoceps in Turkey (Kersting and Baspinar 1997). Molecular methods, immunological properties, and DNA sequences of genomes of these pathogens are bases for identification. Detection in plant hosts and in natural vectors and characterization and differentiation of strains have been possible by employing immunodiagnostic and nucleic-acid-based methods (Narayanasamy 2001). Sesame phyllody phytoplasma (SPP) is detected by various ELISA formats. Indirect ELISA and protein-A-coating (PAC) forms of ELISA were more sensitive in detecting SPP in sesame and other plant hosts and in the leafhopper vector Orosius albinctus (Srinivasulu and Narayanasamy 1995a). Antiserum specific for suaeda (Suaeda baccatum) witches’ broom phytoplasma (SWBP) occurring in Iraq did not react with the extracts from SPP-infected sesame plants, indicating that these phytoplasma were not serologically related (Al-Ani et al. 2001). Hybridization using cloned chromosomal

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and extrachromosomal DNA fragments associated with the SPP as probes and the polymerase chain reaction (PCR) procedure to amplify the 16S rDNA of the phytoplasma were useful in detecting SPP in the field sesame samples. SPP appears more closely related to the phytoplasma associated with phyllody and witches’ broom symptoms than to the phytoplasma that induces white leaf symptoms in sugarcane (Nakashima et al. 1995). In Korea, sesame and jujubes (Zizhyphus jujube) infected by phytoplasma revealed the presence of phytoplasma in the phloem sieve elements. The DNAs extracted from the stems of infected plants were amplified by PCR assay, using a primer set specific to 16S rRNA gene for known phytoplasma. A 1.4 kb band in both infected sesame and jujube plants was amplified, suggesting that SPP might be related to phytoplasma in jujubes. Restriction digestion of the amplified band by restriction enzymes Alu I, Hae III, Hind I, or Taq I showed that phytoplasma infecting sesame and jujubes belonged to different phytoplasma groups (Seok et al. 1997). The study on the phylogenetic relationship of SPP and Richardia sp. phytoplasma (RP) on the basis of 16S rDNA sequences revealed that these phytoplasma are closely related. The distribution of SPP in sesame and Richardia plants was traced using chromosomal DNA fragment SP 28 of SPP as a DNA probe. SPP is detected not only in flowers showing symptoms but also in symptomless leaves and stems in SPP-infected sesame and Richardia plants. The results suggested that inhibition of the morphogenesis of the floral organs by metabolites elaborated by SPP, rather than an interruption of phloem flow by SPP, might result in the proliferation of floral tissues leading to phyllody symptom (Nakshima et al. 1999). SPP is detected by the universal phytoplasma primer pair P1/P7 in sesame plants showing phyllody symptoms that include a wide range of plant species affected by phytoplasma (Salehi et al. 2000) A naturally infecting potyvirus was isolated from sesame plants in Georgia (USA) and characterized. Phylogenetic analyses of the 3’ terminal region of the viral genome suggested that this virus belongs to the passionfruit woodiness potyvirus subgroup, and is most closely related to cowpea aphidborne mosaic virus (CABMV) and South African passiflora virus. The virus infecting sesame is a strain of CABMV, based on the sequence homology. The taxonomic status of this potyvirus was established using degenerate primers, reverse transcription-polymerase chain reaction (RT-PCR), and cloning and sequence analysis (Pappu et al. 1997). The virus particle morphology and serological properties of sesame necrotic mosaic virus (SNMV) indicated that this virus might belong to Tombus viridae (Yong et al. 2000). Indirect ELISA and growing on tests showed that peanut stripe potyvirus (PStV) is not transmitted through sesame seeds. However, the primary source of PStV causing sesame yellow mosaic disease was peanut (groundnut) infected by PStV (Kunrong et al. 1999).

Pathogenesis Pathogenesis, the process of disease development, begins as soon as the pathogen reaches the infection court in a compatible (susceptible) interaction. Attachment of pathogens to plant surface, germination of spores or pathogenic units, penetration of host, colonization, and symptom expression are distinct phases of disease development. In the case of incompatible interaction, the progress of disease may be hampered at one or more of these phases of disease development (Narayanasamy 2002). The microbial pathogens produce various kinds of enzymes and toxins that have a critical role in the release of nutrients and expression of characteristic disease symptoms. The rate of development of fungal pathogens is influenced by the availability of required nutrients and favorable environmental conditions. The pathogenic potential (virulence) of isolates/strains may vary considerably. Under optimal conditions, potato dextrose agar (PDA) medium encouraged the mycelial growth of the I-14 isolate of Macrophomina phaseolina, which causes root rot disease in sesame. Of the 15 isolates tested, I-14 was the most virulent. Variations in the colony color and production of pycnidia and sclerotia by different isolates were also evident (Karunanithi et al. 1999; Pereira et al 1995). Penetration of root tissue by M. phaseolina followed. This fungal pathogen formed appressoria on the epidermis

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of inoculated sesame seedlings. The histological studies showed the inter- and intracellular hyphae invading the root tissues and later colonizing the stem tissues, fruits, and seeds progressively with lapse of time (Smits-Brieds 1998). The culture filtrate of Alternaria alternata drastically reduced seed germination, shoot elongation, and root length (Bavaji et al. 2000) The extent of invasion of seed tissues by Alternaria alternata in asymptomatic and symptomatic seed is assessed by histopathological methods. The mycelium of A. alternata is found in all seed components in symptomatic seeds. Mycelial aggregation in all layers of seed coat, endosperm, cotyledons, and embryonal axis occurs. In asymptomatic seeds, infection was restricted to the seed coat alone (Dubey and Singh 2004). Some fungal pathogens, such as Aspergillus flavus, in addition to inducing diseases in plants, are responsible for several ailments in humans and animals when foods and feeds contaminated with mycotoxins produced by them are consumed. A number of species of Aspergillus produce the mycotoxin aflatoxin in infected seeds of many cereal and oilseed crops. Aflatoxin production by A. flavus increased with increasing sesame seed moisture, reaching the maximum at 14% moisture level. Substantial amount of aflatoxin is detected even with a low initial inoculum (10 spores/g of seeds) of A. parasiticus (King and Rong 1997). In the case of A. flavus, the minimum moisture content of sesame seeds required for aflatoxin production is 10%; the optimal temperature is 30o C. No aflatoxin was produced at 15o or 40oC. The highest aflatoxin was produced with an inoculum level of 107 cfu/g (Shahin 1998).

Epidemiology The incidence, further development, and dispersal of microbial pathogens depend primarily on host, pathogen, and environmental factors that constitute the classical “disease triangle.” Temporal and spatial components influence the development of disease in a given geographical location. In the case of vectorborne phytoplasma and viral diseases, the population of vector species and the efficiency and period of retention of the pathogen by the vector have considerable influence on the incidence and spread of these diseases.

Effect of Seed Infection Seed infection levels influence seedborne fungal and bacterial diseases. The severity of Alternaria leaf spot was assessed in a field sown with sesame seeds having six infection levels (Ojiambo et al. 2003). The most severe leaf spot disease occurred on plants established from seeds with 8% infection, and the least disease intensity was found on plants growing from disease-free seeds. Disease severity increased with increase in infection level, indicating the critical role of seed infection in disease incidence under field conditions. The transmission efficiency of A. sesami from seeds to sesame plants varied from 0% to 40.7% depending on the sesame genotype. Levels of transmission were higher in SPS SIK013 and SPS SIK121 than in SPS SIK110 (Ojiambo et al. 2003). In such cases, use of disease-free seeds and selection of genotypes/cultivars that do not allow transmission of the pathogen to plants is an important strategy to avoid considerable disease incidence (Ojiambo et al. 2000a,b; Weiss 1971).

Effect of Sowing Dates The extent of loss caused by microbial pathogens in sesame seems to depend on the stage of growth of plants at the time of infection and climatic conditions during crop growth. In the United States, Alternaria spp. generally appeared late in the season (Culp and Thomas 1964). High humidity and rainfall favors disease incidence (Cano and Lopez 1950). The influence of plant age at disease incidence on infection of seeds by A. sesami at five distinct plant ages was assessed. Seed infection was the highest in plants infected at 8 and 10 weeks of age and least in plants infected at 4, 6, and 12 weeks of age (Ojiambo et al. 1999).

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Sowing date is key to the incidence of powdery mildew disease in Assam State, India. The percent disease index in early-sown sesame (first half of August) was higher (77% to 85%) than in sesame sown late (47%) (second half of September). However, the effect of disease was inconsequential, since the yield of early-sown crop was higher compared with late-planted sesame. The levels of resistance of cultivars to powdery mildew varied considerably, indicating the need to select less susceptible cultivars (Hazarika 1998). Alternaria leaf spot severity increased the more sowing was delayed. The interaction between cultivar and sowing dates was significant. The variety ‘T-13’ showed less disease compared with other cultivars tested, irrespective of sowing dates, indicating the tolerance of the variety to the leaf spot disease (Tripathi et al. 1998). The effect of sowing date on the incidence of phyllody disease is noteworthy. By adjusting the date of sowing to avoid the buildup of vector population, it may be possible to reduce the incidence of the disease. Sesame sown in January through March contracted high disease levels, while the disease incidence was low in crops sown in March through October under the conditions in Coimbatore (Srinivasulu and Narayanasamy 1995b). The period for suitable sowing has to be determined for specific geographical locations to avoid the infection in early growth stages, when plants are highly susceptible to disease.

Weather Factors The influence of weather on the development of microbial pathogens and the diseases induced by them is immense. Blight caused by Phytophthora parasitica var. sesami was favored by temperatures of 28–30oC, whereas temperatures above this reduced the activity of the pathogen. High soil moisture and rain increased the incidence of the disease in clay soils (Gemawat and Prasad 1965; Mazzani 1966). Blight due to Helminthosporium sesami inflicted more damage in young plants, and when humidity was high (Stone 1959). Climate influences the incidence of bacterial blight of sesame caused by Xanthomonas campestris pv. sesami. The intensity of the disease reached maximum level when the average temperature was 29–29.4oC in September, with a relative humidity of 88–90.5% and rainfall between 8.9 and 9.97 mm. Disease intensity declined as the temperature, rainfall, and relative humidity reduced by the end of September during 1993 and 1994 (Srivastava et al. 1997). The incidence of bacterial wilt disease caused by Ralstonia solanacearum is correlated with mean temperature, rainfall, and relative humidity during the crop growth period (Hazarika and Das 1999). There was a positive correlation between phyllody disease incidence and maximum temperature and maximum sunshine hours, and a negative correlation with relative humidity. Maximum temperature exerted a favorable influence on the vector population. An increase in maximum temperature by 1oC resulted in increase in phyllody disease and leafhopper population by 0.98% and 1.7 units, respectively (Srinivasulu and Narayanasamy 1995b).

Sources of Infection The sources of infection for diseases may be either internal or external, influencing the disease incidence substantially. Occurrence of diseased plants in groups, especially in the case of virus diseases, may indicate that the spread of the disease is initiated from the internal sources such as infected volunteer plants (both crops and weeds) and plants growing from infected seeds or seedlings transplanted in the main field. When the sources of infection are external (remaining outside the field in question), the infected plants are found scattered (Narayanasamy and Doraiswamy 2003). The primary sources of Peanut stripe virus (PStV) infecting the sesame crop were the peanut plants infected by PStV that was spread by the aphid vectors Aphis craccivora, A. glycines, A. gossypii, and Myzus persicae. The efficiency of M. persicae in transmitting PStV was the greatest (35%), while the other aphid species were poor transmitters (< 2%). The disease incidence is closely related to aphid occurrence (Yong et al. 1995). The extent of disease incidence is related to the aphid

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population at the early growth stage of sesame. Average temperature, rainfall, and number of rainy days in a 20-day period from late June to early July had a substantial influence on the disease incidence in China (Kunrong et al. 1999).

Disease Management Strategies The disease management systems may be developed based on various principles: (1) reduce the introduction of pathogen(s) (exclusion), (2) suppress the initial inoculum (eradication), and (3) improve the level of host resistance to disease(s) (immunization). The strategies of disease management may be grouped as biological and nonbiological methods or chemical and nonchemical methods (Narayanasamy 2002).

Agricultural Practices Agronomic practices such as use of disease-free seeds, adoption of proper spacing and dates of sowing, and application of adequate organic manures, in addition to efficient use of balanced fertilizers, maintenance of optimum soil moisture, and clean cultivation by eradicating all weeds and volunteer plants that may harbor microbial pathogens capable of infecting the crops, have been demonstrated to be effective in reducing the incidence of diseases in various crops. However, crop requirements and environmental factors impose limitations on their effectiveness under certain conditions in different geographical locations. The importance of using disease-free seeds to reduce the incidence of diseases caused by microbial pathogens is well known. Use of healthy seeds prevents the introduction of pathogens into fields and to new areas. Many workers recommend optimum plant density (seed rate) and sowing at appropriate times, that is, when disease incidence is low. Modern agricultural practices have frequently created conditions favorable for introduction and spread of microbial pathogens. High yielding (but highly susceptible) varieties, application of high doses of nitrogenous fertilizers, and high density planting may help realize higher yields in certain years, but these conditions are also very favorable for disease development, necessitating the application of chemicals against which the pathogens are likely to develop resistance sooner or later. Furthermore, continuous monoculture of genetically similar plants in a location leads to perpetuation of the pathogen and endemism of the disease in that area (Narayanasamy 2002).

Physical Methods Use of heat in various forms to eliminate the pathogens from seeds and soil as a disease management strategy has been considered. But success is limited, and in addition there is the difficulty of maintaining the temperature levels consistently for the required time. Loss of seed viability and high cost of soil treatment are limiting factors for large-scale application. Hot water treatment (53oC for 30 minutes) provided effective control of leaf spot disease caused by Cercospora sesamicola and C. sesami (Mohanty 1958). The effect of soil solarization (a simple nonchemical technique that captures radiant heat energy from the sun and causes physical, chemical, and biological changes) for six weeks combined with plowing and irrigation reduced the incidence of stem-root rot disease caused by M. phaseolina dramatically to 0.5% and 0.0% from 51.6% and 95.5% in the control (without solarization) during two years of field experiments. In addition, seed germination, plant height, number of capsules per plant, and seed yield reached the maximum levels following solarization for 6 weeks with plowing and irrigation (Chattopadhyay and Sastry 2001). The harmful effects of the mycotoxigenic fungi Aspergillus spp. are reduced by eliminating seed infection. By maintaining optimum levels of seed moisture, the growth of and aflatoxin production by A. parasiticus may be reduced considerably (King and Rong 1997). The moisture content of sesame seeds required for aflatoxin production by A. flavus was 10%. There was no aflatoxin production at 15o or 40oC, and maximum production was reduced substantially. Irradiation with

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gamma rays decreased aflatoxin production in the seeds, and the decrease was proportional to the irradiation dose. Irradiation at a dose of 2.5 kGy entirely prevented aflatoxin production even under conditions optimum for fungal growth (Sahin 1998).

Biological Control The possibilities of employing microorganisms antagonistic to microbial pathogens infecting assorted crops have been explored with varying degrees of success. The effectiveness of biocontrol agents (BCAs) in controlling the diseases is frequently found to be inconsistent and influenced by several factors, such as the nature of the microbial pathogen, the ability of the BCAs to survive in varying agro-climatic conditions, and the nature of crop plant and the tissue to be protected (Narayanasamy 2002, 2005b). The biocontrol potential of Trichoderma viride, T. harzianum, and Bacillus subtilis against M. phaseolina–caused root rot disease of sesame was tested. Seed treatment with these BCAs resulted in a large reduction in levels of disease incidence (Dinakaran et al. 1995). Soil application of T. viride was also effective against this pathogen (Wuike et al. 1995). However, soil application of BCA is cumbersome and requires large quantities of BCA, with a consequent increase in application cost. Treatment of sesame seeds with T. harzianum and T. viride reduced the root rot incidence to 10.1% and 12.8% respectively, from 60% infection recorded in controls. In addition, root length, shoot length, yield, and oil content of seeds increased with seed treatment with BCAs (Sankar and Jeyarajan 1996a). They assessed the viability of Trichoderma and Gliocladium in talc-based powder formulation for treatment of sesame seeds. The population of the BCAs in treated sesame seeds did not decline for up to 40 days after treatment. But after 120 days, only 55–68% of the initial population of the BCAs remained (Sankar and Jeyarajan 1996b). Wilt disease caused by Fusarium oxysporum f. sp. sesame (Fos) could be effectively controlled by seed treatment with T. harzianum and T. viride in Maharashtra State, India. The effectiveness of the BCAs was comparable to the fungicides carbendazim, thiophanate-methyl, and chlorothalonil used for seed treatment (Wuike et al. 1998). Bacillus polymyxa (Paenibacillus polymyxa) strain KB-8 was antagonistic to Fos. The antibiotic purified from the cultures of the BCA was effective at concentrations of 13 and 26 µg/mL applied for drenching the soil, compared with 6.5 µg a.i./mL of benomyl required to have the same level of control of the disease under greenhouse conditions (Wook et al. 1999). Combination of soil application and seed treatment with Trichoderma spp. isolated from the rhizosphere of sesame plants reduced the incidence of wilt disease (Sangle and Bambawale 2004).

Improving Host Resistance to Diseases Resistance might be enhanced by (1) incorporation into susceptible cultivars of disease-resistance genes (R) from wild relatives/genotypes by conventional breeding methods, (2) molecular methods, and (3) inducing resistance in susceptible cultivars by applying inducers of disease resistance.

Breeding for Disease Resistance The evaluation of resistance in sesame genotypes under field conditions may be useful to eliminate the susceptible entries based on the percentage disease index (PDI) scores using a standard disease severity scale (1–9) (Manoharan et al. 1996; Rong et al. 2001; Tripathi et al. 1998a). The entries showing no disease or less PDI should be tested under controlled conditions, since the disease pressure under natural conditions may not be uniform for all entries or to the required level. Only a few reports provide results of experiments conducted under controlled conditions. In Egypt, the cultivar ‘Giza 32’ was less susceptible to both M. phaseolina and F. oxysporum, compared with five other varieties and genotypes tested (Gabr et al. 1998). By inoculating the sesame genotypes using wooden toothpicks containing mycelium and sclerotia of M. phaseolina, the genotypes PI

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158922, Sesamum radiatum, S. cf radiatum, and UCR-12 were moderately resistant, as they showed slight necrosis around the point of inoculation (Pereira et al. 1996). Various sesame cultivars were evaluated for their resistance to Aspergillus flavus–producing aflatoxin. The chemical analysis of the differing constituents of sesame seeds of susceptible and resistant cultivars indicated that lower levels of sodium and higher contents of potassium might be associated with resistance to A. flavus (Saber 1998). Field evaluation for selecting reliable sources of resistance to phyllody disease is inadequate. Some sesame cultivars, such as ‘Si 259,’ ‘Si 2640,’ ‘Si 2780,’ and ‘Si 3289,’ were free from phyllody infection. However, when they were artificially inoculated using infective leafhoppers, they were found to be susceptible to the disease. Among other related species tested under controlled conditions, Sesamum alatum Schum. et Thonn. was highly resistant to phyllody disease (Srinivasulu and Narayanasamy 1992). This study provided a reliable source of resistance to sesame phyllody phytoplasma (SPP), satisfying the basic requirement for initiating a resistance breeding program, using S. alatum as donor of resistance to SPP. The experiments conducted to understand the mechanism of resistance to SPP showed that S. alatum resistance was due to its resistance to the leafhopper vector, rather than to SPP (Parani et al. 1996). Sodium dodecylsulphate-polyacrylamide gel electrophoresis (SDS-PAGE) analysis of sesame seed proteins indicated that five male-specific proteins had been transferred to the putative hybrid. The hybrids could be differentiated by using the random amplified polymorphic DNA (RAPD) profiles of parents and hybrids generated by amplification of genomic DNA by employing primers of arbitrary sequence (Parani et al. 1997). The pattern of inheritance of resistance to leaf curl disease and lodging was investigated (Falusi and Salako 2003). Two independently assorting genes with both dominant alleles ‘F’ and ‘L’ controlled resistance to leaf curl disease and lodging, respectively. The recessive alleles ‘f’ and ‘l’ produced plants that were not resistant to leaf curl disease and lodging. Mutation breeding methods have been attempted to create variation in desired plant characters, including resistance to diseases caused by microbial pathogens. Gamma rays generated mutants (1076) of sesame (S. indicum) in the M3 and M4 generations (Uzun and Cagirgan 2001). They were evaluated for their resistance to Fusarium wilt disease by growing the test entries in wilt-sick soil in Turkey. Sixteen mutant lines showed resistance to the disease, based on a 1–9 visual field scoring scale. They confirmed resistance of three mutant lines with further testing under controlled conditions.

Biotechnological Approaches Variation in the levels of resistance to crop diseases has been noted in plants regenerated from organ cultures, calli, and protoplasts. The variability expressed by regenerated calli is somaclonal variation. Epicotyl segments of sesame cv. Giza 25 were exposed to the culture filtrates of M. phaseolina and Fusarium oxysporum f. sp. sesami (Fos) (Abd-El-Moneem et al. 1997). Of the 112 somaclones evaluated for resistance to these pathogens, only S2 plants showed a higher level of resistance to both charcoal root rot and wilt diseases caused by the pathogens. In addition, these plants had greater plant height, fruiting branches/plant, capsules/plant, seed yield/plant, peroxidase (PO) activity, and phenolic compounds in root tissues. The results suggested that the resistance of the S2 clone to root rot and wilt diseases could be attributed to increased contents of either PO or phenolic compounds in plant tissues.

Application of Chemicals Microbial pathogens may be managed with some chemical compounds. Their effects are highly visible. Chemical use, however, is restricted because of (1) the environmental pollution, (2) persistence of chemical residues in harvested produce beyond tolerable limits, and (3) development of resistance in pathogens to chemicals. Furthermore, in the case of low value crops such as sesame, the high cost of systemic chemicals is another limiting factor, as the cost-benefit ratio is likely to be low.

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Fungicides The mycoflora associated with sesame seeds are known to reduce seed germination, seedling vigor, and crop stand, in addition to causing diseases in grown plants. Application of metalaxyl, carbendazim, and mancozeb protected the plants growing from treated seeds (Mahatma et al. 2004). Treatment of seeds with thiram or captan (2.5 g/kg) or mancozeb (3.0 g/kg) was effective in the elimination of and protection of plants against wilt disease. Soil treatment with thiram (30 kg/ ha) reduced the spread of the disease. Seed treatment with captan provided protection against Cercospora leaf spot disease. Foliar application of mancozeb may be required for restricting the incidence of the disease in the later stages of crop growth. Incidence and spread of root rot disease may be contained by seed treatment with carbendazim (2 g/kg), followed by soil treatment with thiram and spraying with mancozeb (Das 1997). The effects of seed treatment with benomyl and carboxin on the development of Fusarium solani, Rhizoctonia solani, and Macrophomina phaseolina were assessed under greenhouse conditions. Although the fungicidal treatment was effective in reducing the disease, the growth parameters, seed yield, and protein and oil contents of seeds was comparable to the untreated control (Shalaby 1997; Shalaby and El-Korashy 1996). Phytophthora blight disease incidence could be restricted and loss from the disease could be reduced by spraying copper oxychloride (0.3%) three times, at 20, 40, and 60 days after sowing, as tested in Assam, India (Kalita et al. 2002). Of the fungicides tested, mancozeb was the most effective in reducing the percent disease index (PDI) of Alternaria blight disease (Narute and Utikar 1994). The application of mancozeb and streptocycline provided the most effective control of leaf blight caused by A. sesami and increased the seed yield and benefit-cost ratio favorably (Shekarappa and Patil 2001). In the case of Cercospora leaf spot disease, foliar sprays of carbendazim (0.05%) or thiophanate-methyl (0.2%) three times at 10-day intervals provided the best control. Substantial yield increase (49.7%) through fungicide application, with a benefit-cost ratio of 3.3 over control, was also recorded (Tripathi et al. 1996).

Natural and Synthetic Compounds Several natural and synthetic compounds were evaluated for their control of microbial pathogens infecting sesame. Extracts of Helichrysum flowers, castor oil, and aminobutyric acid (ABA) protected sesame plants efficiently against M. phaseolina and increased seed yield under field conditions (Shallaby et al. 2001). A combination of seed and soil treatments with ascorbic acid and salicylic acid was more effective than benomyl in controlling sesame wilt disease (Abdou et al. 2001). Herbicide application appeared to offer some control of dry root rot and leaf blight of sesame caused by M. phaseolina (Mustaq Ahamad and Vyas 1997). Likewise, combined application of bleaching powder, streptocycline, and mustard oil cake or asafetida, turmeric, and water controlled bacterial wilt disease in Assam, India (Dubey et al. 1996). Successful management of the diseases of sesame caused by microbial pathogens depends on the availability of information on the nature of the pathogens, the sources of inoculum, the existence of favorable environmental conditions required for the incidence, and the spread of the pathogens and the level of susceptibility/resistance of the cultivars. It is essential to integrate all disease management strategies that are effective in reducing the adverse effects of the disease(s) to provide greater level of protection to the crops from seed germination to harvest of the produce. A preference for nonchemical methods will help preserve the environment in addition to achieving the expected yields.

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Cultivation 17 Sesame and Use in China Zhao Yingzhong Contents History.............................................................................................................................................284 Production.......................................................................................................................................284 Distribution.....................................................................................................................................284 Major Sesame Research Institutions in China................................................................................ 285 Sesame Germplasm Resources in China......................................................................................... 285 Cultivation Practices....................................................................................................................... 286 Growing Season......................................................................................................................... 287 Cultivars..................................................................................................................................... 287 Rotation and Intercropping........................................................................................................ 287 Seeding Dates............................................................................................................................. 288 Soil............................................................................................................................................. 289 Seedbed Preparation and Labor................................................................................................. 289 Soil Fertility............................................................................................................................... 289 Seed Preparation........................................................................................................................ 289 Planting Methods.......................................................................................................................290 Seeding Rates.............................................................................................................................290 Thinning.....................................................................................................................................290 Planting Density.........................................................................................................................290 Cultivation and Hoeing.............................................................................................................. 291 Herbicide Application................................................................................................................ 291 Diseases........................................................................................................................................... 291 Insect Pests...................................................................................................................................... 292 Drainage and Irrigation................................................................................................................... 292 Harvesting....................................................................................................................................... 293 Chemical Constituents of Sesame................................................................................................... 293 Utilization of Sesame in China....................................................................................................... 294 Sesame Oil................................................................................................................................. 294 Sesame Seeds, Whole and Hulled.............................................................................................. 294 Pharmaceutical Uses.................................................................................................................. 295 Sesame Leaves........................................................................................................................... 295 References....................................................................................................................................... 296

283

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Table 17.1 China’s Sesame Growing Area, Productivity, and Production Shown in 5-Year Averages, 1961 to 2005

Area (kha) Yield (kg/ha) Production (k tons)

1961– 1965

1966– 1970

1971– 1975

1976– 1980

1981– 1985

1986– 1990

1991– 1995

1996– 2000

2001– 2005

730.3 349.7 255.8

622.5 434.2 269.8

567.8 432.2 246.0

674.7 435.0 293.6

896.0 526.6 473.6

794.1 592.5 471.0

702.3 756.5 529.2

654.2 1022.1 670.3

702.7 1057.2 744.3

History Sesame (Sesamum indicum L.) has been cultivated in China for over 2000 years (Laufer 1919). Ancient agricultural books such as Qi Min Yao Shu of the late Wei Dynasty (AD 220–265) and Wang Zhen Agricultural Book of the Yuan Dynasty (AD 1271–1368) indicate that sesame was introduced by Zhang Qian from Central Asia to China in the second century BC and first planted in the Yellow River basin, and then spread to the Yangtze River valley and the Pearl River region. Sesame seeds recently unearthed from two tombs in Zhejiang Province (Chen 1987) reveal that China has planted sesame between 770 and 480 BC, suggesting a date 200 to 500 years earlier than previously stated. In ancient times, Chinese burned sesame oil for light and used the soot for their ink blocks. This legacy survives today as India ink, prepared from the soot of charred sesame stalks.

Production Today China ranks first in the world in total sesame production (FAOSTAT 2006). China is also one of the most important countries in sesame exports and imports. China exports about 100,000 metric tons (T) of sesame seed and imports around 40,000 tons annually, in most years, ranking third and fifth in world trade, respectively (FAOSTAT 2006). The area of sesame cultivation in China has covered 700,000–800,000 hectares (ha) in recent years, ranking fourth largest after India, Myanmar, and Sudan. Moreover, China has the highest seed yield, much higher than those of other countries. China also surpasses the world’s average productivity. In 2005, China’s sesame-growing area was 660,000 ha, its productivity was 1098.5 kg/ha, and its total production was 725,000 tons, contributing 21.8% to total global production (FAOSTAT 2006). Sesame is a small-scale crop in China compared with staple crops such as rice, maize, wheat, soybean, rapeseed, cotton, potato, peanut, tobacco, sugarcane, sunflower, millet, barley, and mung bean (MAPRCSTAT 2006), but farmers like to plant it as an industrial crop. China’s sesame-growing area has fluctuated widely in recent years. From 1981 to 1985, the area was 896.0 thousand ha, but between 1996 and 2000 only 654.2 thousand ha. Sesame productivity and production in China have increased steadily since 1961, and markedly after 1996 (Table 17.1) (FAOSTAT 2006).

Distribution The distribution of sesame covers almost all Chinese provinces, and is divided into seven ecological regions (Chen 1987): Northeast and northwest, spring planting; Northern, spring; Huanghuai, summer; Jianghan, summer; Middle and lower reaches of Yangtze River, summer, with intercropping; Southcentral and southern, spring, summer and autumn; Southwest plateau, summer with some spring and autumn. Of these, the Huanghuai and Jianghan regions are the highest-producing areas. China has three broadly demarcated sesame-growing zones: spring sesame in northern China, summer sesame in central China, and spring, summer, and autumn sesame in southern China (Chen 2002). The major sesame-growing provinces are Henan, Anhui, and Hubei; all are located in central China. The area and the production of the three provinces together covered 71.1% and 71.7%,

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Table 17.2 Sesame Area Cultivated, Productivity and Production in Key Provinces, 2004 and 2005 Area (kha)

Henan Anhui Hubei Jilin Jiangxi Shaanxi Hebei Jiangsu National

Productivity (kg/ha)

Production (k tons)

2004

2005

2004

2005

2004

2005

204.7 121.3 111.2 34.7 29.2 17.1 16.2 11.9 624.2

210.5 109.0 102.5 32.1 30.6 16.6 15.2 11.9 593.3

1108.9 1129.4 1384.9 951.0 787.7 1052.6 925.9 1596.6 1127.8

1049.0 821.7 1334.0 1099.6 827.4 1014.2 958.3 1535.9 1054.1

227 137 154 33 23 18 15 19 704

221 90 137 35 25 17 15 18 625

respectively, of the national total in 2005 (MAPRCSTAT 2006). The reason this area is the centralized production region is that Henan, Anhui, and Hubei provinces, in sub-tropical and warm temperate zones, have abundant illumination and rainfall and high temperature, as well as fertile soil favorable to sesame growth. Moreover, farmers in this area have grown sesame traditionally. After these provinces are Jiangxi, Hebei, and Shaanxi, with the remaining provinces cultivating relatively smaller amounts of sesame. Table 17.2 and Figure 17.1 show the major growing areas, productivity, and production in the most significant sesame-growing provinces (area > 10 kha) in 2004 and 2005. Of the three major provinces, Henan has the biggest area and production: 210,500 ha and 221,000 T in 2005, representing 35.48% of China’s sesame area and 35.36% of China’s production. The productivity in Hubei is the highest of the top three provinces, 1334.0 kg/ha in 2005, higher by 27.17% and 62.35% than Henan and Anhui provinces, respectively; and its production ranks second in the country.

Major Sesame Research Institutions in China Sesame, one of the most important oil crops in China, is studied extensively by focused institutions, including the Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences (CAAS), the foremost sesame research institution in China, located in Wuhan, Hubei Province; Henan Academy of Agricultural Sciences; Zhumadian Institute of Agricultural Science of Henan Province; Hebei Academy of Agricultural and Forestry Sciences; and the Jiangxi Academy of Agricultural Sciences.

Sesame Germplasm Resources in China Sesame germplasm collection was initially patchy, initiated by experts such as Cheng Kansheng in Guangxi in the late 1930s. China had assembled more than 5200 accessions (over 5000 from 29 provinces in China) by the end of 1995. China carried out two national germplasm collection missions. The first, from 1956 to 1963, collected over 3200 accessions from 24 provinces; however, some of these had been lost by 1987. The second mission, from 1979 to 1986, for supplementary collections, assembled ca. 2000 accessions from 23 provinces. From 1986 onwards, collection continued haphazardly; 1200 more accessions were assembled by 1995. Today, the collection includes

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Jilin

Hebei

Shaanxi Henan Hubei

Jiangsu Anhui

Jiangxi

Growing area: >100 kha >25 kha >10 kha

Figure 17.1  The major growing areas, productivity, and production in the most significant sesame-growing provinces.

a wild species called “Congo wild sesame” (unidentified) from the Democratic Republic of Congo, of determinate, non-shattering, and golden seed color types (Feng 1999). As the collection of more germplasm resources continued, their extensive identification and evaluation were undertaken. Characters evaluated include plant height, branching pattern, flower number per leaf axil, locule number per capsule, capsule length, stem hairiness, flower color, seed color, 1000-seed weight, stem color at maturity, capsule dehiscence, sowing date, maturity date, total growth cycle, waterlogging tolerance, Fusarium wilt resistance, charcoal rot resistance, oil content, protein content, and fatty acid (palmitic, stearic, oleic, and linoleic) content (Feng 1999). Based on these characteristics, The Catalogue of Varietal Germplasm Resources of Sesame in China (3 volumes), with 4251 accessions (Chen 1987), and The Varietal Record of Sesame in China, containing 290 accessions (Feng 1999), were published. The Oil Crops Research Institute of the CAAS, in collaboration with the International Plant Genetic Resources Institute (IPGRI), developed a Chinese sesame core collection containing 453 accessions (Zhang et al. 2000). Since 1986, China carried out the regeneration of sesame germplasm resources without interruption. In 1995, 4251 accessions were given to the national long-term gene bank in Beijing for storage at –18° C, and to the mid-term gene bank in Wuhan. Additionally, each province, city, and municipality maintains its local materials (Feng 2000).

Cultivation Practices Zhang and Li (1991), Yan and Zhao (2001), and Chen (2002) reviewed techniques recommended for high yield and good quality in sesame planting.

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Growing Season Sesame, having originated in the tropics, performs best in China’s summer season. Sesame likes relatively high temperatures and ample illumination. It germinates when the temperature is between 16° and 36°C, with the optimum temperature for germination between 24° and 32°C. China contains both sub-tropical and temperate climatic zones; hence, the sesame-growing season varies slightly from region to region. Farmers can plant sesame between April and July and commercially grown varieties require 80–120 days to reach physiological maturity. Harvest time is from the end of August through September in most regions.

Cultivars The Oil Crops Research Institute of CAAS initiated sesame-breeding efforts with systematic selection in the 1950s. China had released 58 varieties by 2004; of those cultivars, the Oil Crops Research Institute of CAAS developed more than a dozen, denominated by the prefix ‘Zhongzhi’ (CAAS Sesame). At present, farmers in China grow more than twenty cultivar releases, and some good landraces, such as Wuning Black and Beijing Bawangbian. The principal cultivars grown by each major province are Hubei Province: Zhongzhi 9, 10, 11, 12, 13, 14, and Ezhi 1, 2, 3, 4 Henan Province: Yuzhi 4, 8, 10, 11, Zhuzhi 11, Zheng 97C01, and Luo 12 Jiangxi Province: Ganzhi 2, 3 Hebei Province: Jizhi 3, Ji 9014 Shaanxi Province: Shaanzhi 3 ‘Zhongzhi 9’ is a branched type with four-, six-, and eight-loculed capsules. Its seed is large and black, and is suitable for food and medicine. ‘Zhongzhi 10’ is a branched type, and ‘Zhongzhi 12’ is unbranched. Both have high tolerance to waterlogging and resist charcoal rot and Fusarium wilt, and have high yield potential, wide environmental adaptations, and the desirable white seed coat. ‘Ezhi 1’ and ‘Ezhi 2,’ ‘Yuzhi 8,’ and ‘Zhuzhi 11’ are unbranched types, their seeds large and white, adapted to China’s central region. ‘Ji 9014,’ unbranched, is a black-seeded variety, fit to grow in northern China (Li et al. 2005). Figure 17.2 illustrates hybrid variety ‘Zhongzhi Za No.1’ that we released.

Rotation and Intercropping Sesame is a crop easily infected by soil fungi and bacteria. As many pests can live in the soil for several years, it is vital to grow sesame in rotation with other crops in order to control diseases. Sesame cultivation is classified into spring, summer, and autumn sowing times descending from the northern to the southern areas of China, necessitating different rotation systems. In northern and northwest China, one crop per year is grown, and the rotations are (1) maize – sesame – wheat – soybean – sorghum (2) barley – sesame – wheat – maize – wheat (3) soybean – sesame – wheat – peanut (4) cotton – sesame – wheat – maize (5) sorghum – wheat – sesame – wheat In the Yangtze River and Huai River regions, there is summer sesame with two crops per year, and the rotations are (1) wheat – sesame – wheat – soybean (2) barley – sesame – wheat – maize

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Figure 17.2  Hybrid variety ‘Zhongzhi Za No.1.’

(3) rapeseed – sesame – wheat – cotton (4) wheat – sesame – rapeseed – peanut (5) horse bean (Vicia faba L.) – sesame – wheat – sweet potato The southern part is the autumn planting, with three crops per year, and the regime is (1) soybean – sesame – rapeseed – cotton (2) early rice – sesame – rapeseed – peanut (3) barley – soybean – sesame – wheat (4) horse bean – soybean – sesame – rapeseed In some areas, farmers practice intercropping with soybean, mung bean, sweet potato, peanut, cotton, etc. As sesame plants are taller than these other crops, intercropping makes best use of the available sunlight and increases yield.

Seeding Dates In northern China, the spring planting date is early to mid-May. Earlier than that is not suitable because temperatures plunge some years. In the central area, the foremost sesame-producing region, sowing time is mid-May to early June. Seeding in May is preferred since the earlier the sowing date, the higher the seed yield. Sesame has a long sowing period in southern China, its usual span between April and July. On the other hand, sesame can be planted in early August in southern Guangdong and Guangxi provinces, and throughout the year in southern Hainan province.

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Soil Sesame is adaptable to many soil types, but it grows best on well-drained, fertile soils with medium texture, with pH between 6.5 and 7.5. Sesame does not like heavy clay soils. Very acidic, basic, or saline soils are also not suitable. Since sesame is not tolerant to waterlogging, good drainage is essential.

Seedbed Preparation and Labor As sesame seeds are small, the seedlings grow very slowly initially, and need a well-prepared seedbed for germination. Only the men carry out plowing and furrowing activities; men and women both perform all other tasks. Loamy soil has good texture and holds moisture well, so it is easy to prepare a high quality bed. Sandy clay soil has loose texture and plows easily, but maintains moisture poorly and loses moisture easily if plowed too deeply; therefore, one needs to plow, harrow, and sow quickly. Heavy clay soil is not easily prepared and one needs to plow deeply, harrow heavily, and sow immediately after harvesting the previous crop. Sesame seedbed preparation depends on the soil and growing season. The spring sesame field generally is idle in winter, and one may furrow deeply in autumn or winter after harvesting the previous crop. In the winter season, the furrowed earth freezes and the soil becomes loosened, thus improving the soil texture for growing sesame. The summer and autumn sesame field should be prepared well in advance, as high summer temperature causes the soil to lose water quickly. It is usual to prepare sesame beds 2–3 m wide in central and south China, and over 3 m in the northern part (dry area), with flat surfaces and with about 20-cm-deep ditches between the beds.

Soil Fertility Sesame responds well to fertilizers. To produce 100 kg of sesame seeds, approximately 7–8 kg of nitrogen, 2–3 kg of P2O5, and 6–7 kg of K2O are required (Zhang and Li 1991). This is usually applied as a base fertilizer, before planting. Organic manure is also good for sesame growth. The fertilizer requirement for sesame depends on the fertility of the soil, which varies with soil type and previous land use. Generally, an application of 3.75 to 4.5 T of organic manure (pig, cattle, or human ordure) per ha seems to be adequate. Farmers can also apply chemical fertilizers. The base fertilizer generally contains mostly, or wholly, phosphorus and potassium, and only a fraction of nitrogen. Excess nitrogen dispensed as base fertilizer leads to excessive vegetative growth (Chen 2002). Besides N, P, and K fertilizers, boron, zinc, manganese and molybdenum fertilizers are also beneficial for sesame. For satisfactory production, a balanced fertilizer is needed. Though sesame has a taproot, it has a shallow lateral root system, too. Miao et al. (1998) observed 18 crops (wheat, maize, sorghum, millet, broomcorn millet, buckwheat, soybean, small bean, mung bean, cotton, hemp, sesame, sunflower, peanut, sweet potato, potato, tobacco, and sugar beet) grown widely in northern China and found that the roots of sesame are the shallowest, with most less than 20 cm in depth. Therefore, fertility is essential in the surface layer: 10–17 cm is adequate. At the beginning of flowering, a 75–150 kg/ha urea (nitrogen fertilizer) application is helpful, as the plant takes up a large amount of nitrogen during flowering. In addition, sesame shows good response to foliar feeding, which increases seed yield considerably (Yan and Zhao 2001). For example, 0.3% potassium dihydrogen phosphate sprayed one or two times from flowering initiation to the end of flowering will improve photosynthesis, delay leaf senescence, and increase seed yield.

Seed Preparation Sun basking sesame seed for one or two days before planting is helpful to break its dormancy, improve germination vitality, and enhance strong seedling stand (Chen 2002). Farmers remove the

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shrunken grains and impurities from sesame seeds by wind or water. Doing a germination test is essential for determining seed viability; germination exceeding 90% is ideal. To kill the pathogens carried by seed reserves and so help prevent disease, the seed should be cleaned and treated with water at 55°C for 10–15 minutes or with 10 g of 50% carbendazim (CAS No: 10605-21-7) per kg of seed. This will greatly reduce damping off and boost the stand.

Planting Methods In China, there are three planting methods: broadcast sowing, row sowing, and spot sowing. Broadcasting is widely exploited by farmers who have experience and skill and prepare the seed bed well. This method is quick, the seeds disperse uniformly, and seedlings emerge quickly and healthily, but it is difficult to manage and control the density of the plants. Row seeding is an important method as it provides uniform seed rate and depth, in rows, for easy management and controlled density, but one should thin the seedlings as early as possible in order to prevent competition. Cattledrawn seed plows are drafted for sowing in some areas. There are equal and unequal row space methods. The former is usually 30 to 35 cm and the latter varies, from 30 to 50 cm. The spot sowing method is not popular, and used only in late planting and by farmers who have a small amount of seed or a limited field size. It is easy to obtain a full stand if sowing when the soil has sufficient moisture—6–12% moisture in sandy loam soil, or 12–20% in clay soil—and if no heavy rain occurs for four to five days after seeding. If there is not enough moisture in the soil, it is better to irrigate first and sow when the soil moisture drops to the proper level. Because of its small size, sesame seed should be planted 2–3 cm deep when moisture is adequate.

Seeding Rates Farmers should consider the aforementioned factors in determining the seeding rate: soil pattern, seedbed preparation, soil moisture, and planting depth. Broadcast sowing usually requires 4.5–6 kg/ha seed and row seeding 6–7.5 kg/ha. The seed rate can be as low as 3.75 kg/ha using the spot seeding method. If the seedbed is not fine, if soil moisture is inadequate, or if planting is too deep, the seed rate required may be higher.

Thinning Thinning sesame seedlings is an indispensable practice to provide enough space for growth. It is a labor expense, and timing is crucial. If thinning does not take place in time, seedlings must compete for sunlight, moisture, and nutrients, and they soon become weak and etiolated. The first thinning usually is at the stage when the seedling has a pair of leaves, and the second when it has 2 or 3 pairs of leaves. When the seedling has 3 or 4 pairs of leaves, the last thinning should be done to achieve the intended density.

Planting Density In determining plant density, three factors should be considered: variety characteristics, sowing date, and soil fertility. The density of an unbranched variety can be higher than for branched types, as less above-ground space is used. Sesame sown early or in highly fertile soil demands a lower plant density. The count recommended is 90,000 to 105,000 plants/ha for branched varieties and 120,000 to 150,000 plants/ha for unbranched types, when sown before the end of May. If sesame is sown in early June, the density should be 105,000 to 120,000 plants/ha for branched types and 135,000 to 165,000 plants/ha for unbranched types.

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If the soil fertility is moderate and the sowing date is late, the density should be higher. Trials indicated that sesame sown in early June and following wheat should be about 120,000 plants/ha for branched types and 165,000 to 180,000 plants/ha for unbranched types. If the sowing time is late, as at the end of June or early July, the density should be 135,000 to 180,000 plants/ha for a branched type and 180,000 to 225,000 plants/ha for unbranched types.

Cultivation and Hoeing Sesame growth needs loose soil, so cultivation should commence as early as possible. Early cultivation will improve soil aeration and help the seedlings grow faster. Since lateral roots grow close to the surface of the soil, shallow cultivation of a sesame field is necessary so as not to damage the seedlings. Cultivation is manual, using a sharp hoe, a tool with a narrow, slightly convex blade with a curved neck attached to a long handle. The times and depth of cultivation are based on weather, soil moisture, and seedling age. To avoid waterlogging, it is preferable to practice cultivation on a sunny day with suitable soil moisture, and not on a day before it rains. In general, three to four rounds of cultivation are essential from emergence to first flowering. The first cultivation is shallow, after the emergence of the first pair of leaves. The second is after 2 or 3 pairs of leaves have emerged, and is down to 6–7 cm depth. The third at the 4–5 leaf pair stage may reach 7–10 cm in depth. At the onset of flowering, one additional shallow cultivation is essential. After the plants touch one another with their leaves, it is better to stop cultivation. Sesame grows slowly at first and does not compete well with weeds, thus cultivation also has the role of controlling weeds. Several tillage operations will effectively kill germinating weeds before planting and after emergence.

Herbicide Application There are two types of herbicides used to control weeds in sesame fields: at pre-emergence and postemergence stages. Trifluralin (Treflan, CAS No. 1582-09-8) is a selective pre-emergence herbicide with a relatively long duration. Treflan (48%) is applied at ca. 1.5 L in 450–750 kg water per ha to treat the soil surface, followed immediately by harrowing. Alachlor (Lasso, CAS No. 15972-60-8) and metolachlor (Dual) are both selective pre-emergence herbicides, safe for use with sesame; 48% of the former is applied at 2.25–3.75 L, the latter (as SyngentaTM) 1.5–2.0 L of 96% solution in 750 kg water; the soil surface is sprayed after sowing and before seedling emergence. Clethodim and Gallant (Dowco-453) are post-emergence herbicides effective in controlling weeds. The rate is 12% clethodim (CAS No. 99129-21-2), 375–525 mL in 300–450 kg water, and for 10.8% Gallant, 375–450 mL in 450 kg water per ha sprayed where weed infestation is heavy.

Diseases Li (1989) reported, with incomplete statistics, that thirty pathogens attack sesame in China. Some of the serious diseases are charcoal rot (Macrophomina phaseolina (Tassi) Goid), Fusarium wilt (Fusarium oxysporum f. sp. sesami (Xaprometoff) Castellani), Pseudomonas solanacearum Smith, Rhizoctonia solani Kühn, Phytophtora nicotianae Breda var. sesami Pras., viruses, and leafspots (including Alternaria sesami, Alternaria sesamicola, Corynespora cassicola,) (Yang 1996). Charcoal rot disease is widely dispersed in China. Hubei, Henan, Jiangxi, Anhui, Shangdong, and Hebei provinces are the most seriously affected, with incidence of 10–20%, and as high as 80% in a severe case (Li 1989). Charcoal rot can attack throughout the entire growing season, but it is most damaging from initiation of flowering to maturity. The pathogen can cause seeds to rot and seedlings to die. If infestation occurs after flowering, the plants wither and die. At the end of flowering,

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the infected plants can bear seeds, but the disease leads to the reduction of seed plumpness and oil content. The disease first attacks the roots, plant base, or lower stems, and then infects the cortex and pith; finally the whole plant wilts. The pathogen is a seedborne and soilborne fungus. Seed and soil contamination will increase the incidence. The fungus is a weak parasite; hence, a strong plant will be well protected against infection. Carbendazim (CAS No. 10605-21-7) at 40% (1:700) applied at seedling, bud, and flourishing flowering stages is effective in controlling the disease. Fusarium wilt occurs in northern and central China. Hubei, Jiangxi, Henan, Hebei, Shanxi, Shaanxi, and Jilin are the provinces most heavily hit, with an average incidence of 5–10%, but as high as 30% in some years (Li 1989). The pathogen can infect at any time during the season, but the flowering and capsule-bearing stages are the most vulnerable. At the seedling stage, it causes damping off and reduces crop stands in wet soils. During later stages, the disease causes the plant or leaves to become yellowish, the capsules to become reduced in size and to shatter easily, and the seeds to shrivel. The pathogen is also a seed-borne and soil-borne fungus and infects the plant through the tips of roots or wounded areas. Spraying with 0.2% copper sulfate or carbendazim (CAS No. 10605-21-7) can control this disease. Pseudomonas occurs mainly in the hot and humid southern regions of China, roughly at an incidence of 5%. The pathogen is a bacterium that causes the whole plant to wilt when infected. The bacteria pass the winter in the soil and are spread by flowing water, soil insect pests, or farmers’ tools. Lime (calcium oxide) water or ceresan (mercuric ethyl chloride, CAS No. 107-27-7) and lime powder are useful controls. Rhizoctonia spp. are found on sesame in most areas of China. They attack seedlings, causing damping off and reducing crop stands severely. The pathogen passes the winter in the soil in the hyphal or sclerotial form. Copper sulfate (CAS No. 7758-99-8) or thiram (CAS No. 137-26-8) and carbendazim (CAS No. 10605-21-7) can be used to treat the seed. Phytophtora rot occurs mainly in south China, especially in Hubei and Jiangxi. It may infect any part of the plant. The fungus is soil-borne and moves with surface water. Plants are treated with Bordeaux mixture or copper sulfate.

Insect Pests Many damaging insect pests infest sesame plants, including cutworm (Agrotis ipsilon Hufnagel), aphids (Myzus persicae Sulzer), til-hawk moth (Acherontia styx Westwood), Laphygma exigua Hubner, Antigastra catalaunalis Euponchel, and mirid bug (Cyrtopeltis sp). Cutworm is a serious pest that causes seedling damage throughout China. The usual infestation rate is 5–10%, but may reach as high as 20–40%. It can be controlled by spraying dipterex (CAS No. 52-68-6) as bait or pure solution. Aphids, widely distributed in China, feed on leaves of sesame plants nearly anytime. They suck plant sap, causing leaves to curl and reducing plant vigor, and spread viral diseases. They can be controlled with 40% dimethoate (CAS No. 60-51-5) (1:2000-3000) or 50% azidithion (CAS No. 78-57-9) (1:1500) spray. The til-hawk moth is an insect pest that occurs severely in some years. Its larva, about 10 cm in length, feeds on leaves, young stems, and capsules of one or several plants in a day. A treatment of 40% trichlorfon (CAS No. 52-68-6) (1:2000–3000) or 50% dichlorvos (CAS No. 62-73-7) (1:1000–1500) can be used.

Drainage and Irrigation Sesame is a drought-tolerant crop, and natural rainfall is enough for sesame’s requirements in most years. Peng (1989) reported that under his experimental conditions in Queshan, Henan Province, in 1960, sesame required 3002.55 m3/ha water (converted into 301.2 mm precipitation) during the growing season. It is worth noting that China’s major sesame growing areas receive 300–500 mm

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precipitation. Of course, rainfall distribution is uneven. If there is no rain for a long time, irrigation becomes an indispensable practice. In summer, if there has been no rain for one or two weeks and the plants show leaf droop by 2 PM, irrigation water is required. The number of irrigations depends on soil type, location, and season. Ideally, irrigation should take place before 10 AM or after 4 PM. Fast and light irrigation is most favorable. Sesame roots are extremely sensitive to waterlogging. Plants standing in water for even a few hours may die. Therefore, a narrow seedbed and deep ditch assist water runoff from rain and irrigation. It is important to drain the water immediately after heavy rains. This is manual work done with spades: move soil to the beds washed into the ditches by rains, or hoe, if the pavement of the ditch floor is uneven. When preparing beds, nothing should disturb the flow of water.

Harvesting All sesame varieties planted in China are shattering and have an indeterminate growth habit, the capsules maturing at different times on the plant. If harvested early, the upper capsules remain immature, reducing seed yield and quality. If harvested late, the lower capsules shatter, causing seed loss. Ideally, the optimum harvest time is 15–20 days after end of flowering. Plants are mature when most leaves have fallen off, the stems, leaves, and capsules change color from green to yellow or golden, and the lower capsules start to shatter slightly. There is no obvious change in appearance in some varieties: stems, leaves, and capsules remain green; hence we establish maturity by seed plumpness and color. Farmers use sickles with curved blades to cut sesame plants at the base of the stem (10–15 cm above the ground), swath 20–30 stems into a bundle, and place 4 to 6 bundles, tied at the top with string, together in the field, on a threshing floor, or on a flat roof. Since the maximum daily temperature of most sesame-growing areas in China is about 30° C during the harvest season, most plants dry and the capsules open quickly. In just 4 to 5 days, threshing can begin by beating the bundles with a stick and shaking them upside down onto a plastic or cloth sheet. Two or three sessions, repeated over 2- to 3-day intervals, complete the threshing. After threshing, sesame seeds should be sun-dried for one or two days, and then cleaned and stored.

Chemical Constituents of Sesame Sesame seed has good nutritional value and is rich in fat and protein. Its oil content is 54%, on average, from an examination of 4237 accessions of sesame germplasm in China (Shen et al. 1995). Its fatty acid content is 42.20% oleic acid, 44.33% linoleic acid, 8.56% palmitic acid, and 4.92% stearic acid, as based upon a mean of 3142 accessions (Shen et al. 1995). Oleic acid and linoleic acids, both unsaturated acids, are the chief fatty acids, together being 85% of the total. Linoleic acid, an essential fatty acid, is a major constituent of cell membranes and provides the benefit of reducing serum cholesterol (Huang 2001). Sesame seed contains 22.12% protein, based upon an average from 4239 accessions (Shen et al. 1995), making sesame an important protein source and a good natural food. Sesame contains high levels of sulfur amino acids, which are absent in most foods (Huang 2001). Besides fat and protein, sesame contains 27.7 g carbohydrate, 9.8 g dietary fiber, 5.2 g ash, 620 mg calcium, 513 mg phosphorus, 202 mg magnesium, 14.1 mg iron, 4.21 mg zinc, 4.06 mg selenium, and 38.28 mg vitamin E in 100 g of white sesame seeds. Sesame also contains many kinds of carotenes, lecithin, vitamins B1, B2, B3, and others (Chen 2002). Wang et al. (2004) isolated sesamolin, sesamin, β-sitosterol glucoside, β-D-methyl-galactopyranoside, allantoin, α-D-methylgalactopyranoside, and sucrose from sesame seed. Sesamin, sesamolin, and gamma-tocopherol, the antioxidants in sesame seed, allow sesame oil and products to have longer shelf life, and thus are assets for the food industry. During oil processing,

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sesamolin converts into sesamol and sesaminol (Fukuda et al. 1986; Mohamed and Awatif 1986), constituents that contribute to sesame oil’s strong resistance to rancidity.

Utilization of Sesame in China Chinese make use of sesame in four ways: direct seed use, for extracting oil, in food preparations, and for medical use.

Sesame Oil About two-thirds of the sesame grown in China is consumed as oil. Oil processing is done by one of two methods: the wet (water-substitution) method, and a mechanical method (Huang 2001). The water-substitution method is a traditional method. The oil produced has a unique dense fragrance that most consumers like in China, but it is labor intensive and achieves a low yield (about 40%). The procedure of this method is as follows: 1) sieve to remove mud, sand, weeds, and immature sesame seeds; 2) rinse; 3) sauté seeds in a cauldron fired by electricity, as in most factories, or by sesame stalks, as in some small mills, achieving temperatures up to 220–230°C; 4) reduce smoke, charred powder, debris, and heat with fans; 5) grind seed into paste; 6) add water and stir in cauldron; 7) stir and collect oil. The residual sediment is excellent for poultry and livestock feed; it is also a fine manure. A hydraulic press is used to machine-press sesame oil. The process uses simple equipment, maintains the unique flavor of sesame oil, and retains a high quality of the sesame cake. The procedure of this method is as follows: 1) sieve, wash, roast, and grind as in the water-substitution method; 2) stir in a cauldron at 80–90°C for at least 4 hours; 3) weigh in fixed quantity and make circular flat cakes; 4) press; 5) refine, removing sediments, filtrates, and colloids. The spiral oil-mill method gives the highest oil yield (about 46–48%), but the oil lacks the characteristic scent. The procedure of this method is as follows: 1) clean seeds; 2) roast at 47–50°C; 3) grind and make circular flat cakes; 4) sauté in steaming boiler at about 130°C; 5) press and refine as above (Chen 2002). The cake from both mechanical methods can be used to process sesame protein flour, sesame soya sauce oil and feedstuff. Sesame oil is an excellent edible oil, and is used in industrial preparations of perfumes, cosmetics, pharmaceuticals, soaps, insecticides, and paints. The oil sediment after filtering the machinepressed crude refined oil is a raw material from which an inedible oil can be extracted, and which can be used in mechanical and soap-making industries and in deriving phosphatides, important functional components for cell membranes and emulsifiers for foods.

Sesame Seeds, Whole and Hulled Chinese consume sesame seeds extensively in China as meal, paste, confectionary, and in bakery products. Intact seeds are edible after toasting, alone or mixed with other ingredients, and crushed into flour. As a staple, sesame seeds are available both hulled and whole. The shiny hulled seeds, impurity free, are superior for use by food industries to make high-quality baked goods, buns, rolls, and crackers. The dehulling process by the wet method is as follows: 1) clean the seeds; 2) soak for 5–15 minutes in water at 45–50°C; 3) dry the seeds in an oven at 85–90°C; 4) dehull and winnow (Huang 2001). Sesame curd (tofu) is made using the following method: grind the seeds, filter, emulsify, homogenize, and then form a gelatin by adding starch and agar; sterilize two times to yield sesame cheese. In texture, sesame curd is similar to bean tofu, which is made by adding a small quantity of flocculants such as gypsum (calcium sulfate) to boiled soybean milk and obtaining the coagulation clots. A health drink and milk substitute is prepared from black sesame, with mung bean the main ingredient. The mung beans are soaked for 6–8 hours, and the dehulled black sesame seeds are

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fried; both are added to tap water in the proportion 1:0.05:20 and then are ground and then filtered with a 150–200 mesh sieve. Some ancillary ingredients are added to the extraction, which is then diluted, emulsified, and sterilized (Fang 2003). Sesame, along with peanut, tea, and sugar, is used to make Lei tea (pestle tea), a well-known beverage in Hunan, Guangdong, and Fujian provinces. The procedure: 1) prepare liquid extractions of sesame and peanut separately by grinding, adding water for extracting, and centrifuging, and prepare the tea,; 2) mix them in the ratio 5:3:2 with sugar; 3) homogenize in a high pressure homogenizer at 16.7–17.6 MPa; 4) remove air in a vacuum air pump at 87–93 KPa, 5) sterilize; 6) can (Xie 1997).

Pharmaceutical Uses Medicinal treatments with sesame are many, including to prevent aging, inflammation, cancer, and gall-stones, to blacken hair, and as use as a laxative (Wang et al. 2004). Sesame is a therapy for maladies such as hepatitis, constipation, asthma, coronary heart disease, hypertension, arrhythmia, neurasthenia, and prostate hyperplasia (Chen 2002). Some examples of Chinese formulations follow. Anti-aging: Take equal amounts of black sesame and tuckahoe (Poria cocos Wolf) flour, add some maltose syrup, mix thoroughly, and cut into blocks (30–40 g/block). Eat one block every day after breakfast. Chronic hepatitis: Mix equal quantities of black sesame, black soybean, black rice (blackcoated rice), walnuts, peanuts, and jujube (Chinese date (Ziziphus jujuba Mill.)) with pits removed. Toast, grind, add honey, mix thoroughly, and make pills (10 g/pill). Take one pill morning and evening. Constipation: Cook black sesame and sticky rice into congee, a porridge, and add white sugar. Xu (1996) treated constipation in 87 patients with pastes made from walnut (100 g), black sesame (100 g), and honey (200 g) as a Chinese food remedy, and found that the total cure rate reached as high as 94.25%. Senile asthma: Grind the mixture of 200 g toasted black sesame seeds and 200 g dried walnuts, add 250 g honey, and then add the sap extracted from 100 g ginger. Take 2 or 3 times each day. Neurasthenia (symptoms of fatigue, anxiety, headache, impotence, neuralgia, and depression): Mash 50 g black sesame, 50 g walnut kernel, 50 g mulberry leaf, and 15 g kumquat. Make pills (9 g each). Take 1 pill twice a day. Blackening hair: Mix black sesame oil and 75% ethanol (in equal amounts). Daub the hair after washing, massage, and rinse with warm water after 10–15 minutes.

Sesame Leaves Farmers sometimes use sesame leaves as a vegetable or condiment with cooked noodles in Henan province. Sesame leaves can also be canned (Wang 2004). The process is as follows: 1) collect fresh lower leaves about 20 to 30 days prior to harvest; 2) wash; 3) retain color by soaking in saleratus (sodium bicarbonate) and salt solution; 4) scald leaves in boiling water for three to four minutes; 5) maintain crispness using an ascorbic acid and calcium citrate solution; 6) prepare soup seasoned with sugar, yellow wine, mixed spices, salt, ginger, monosodium glutamate, cloves, and soy sauce; 7) vacuum seal; 8) sterilize and cool; and 9) pack. The processed leaves are green in color and intact in shape. Flavonoids, secondary metabolites in plants, have many bioactivities, including an antioxidant ability, free radical scavenging capacity, helping in the prevention of cancer, aging, and cardiovascular degeneration, and maintaining natural pigment; they are widely used in food industries (Zhang 1999). Huang et al. (2004) reported that the content of total flavonoids in sesame leaves is 0.98%. The optimum conditions for ethanol extraction were as follows: 80% ethanol as extraction

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solvent at 80°C for 2.5 hours, with the ratio of material to solvent 1:25. Using the parameters above, the total amount of extracted flavonoids in sesame leaves was 95.6%.

References Chen, C.Y. 1987. The Varietal Record of Sesame in China [in Chinese]. Chinese Agricultural Press, Beijing. Chen, H.X. 2002. Black Sesame Cultivation and Processing Uses [in Chinese]. Jindun Publishing House, Beijing. Fang, X.Q. 2003. Processing technology on black sesame mung bean milk. Food Science and Technology (4): 83–84. [in Chinese] FAOSTAT. 2006. URL http://faostat.fao.org/site/567/DesktopDefault.aspx?PageID=567 and http://faostat.fao.org/site/535/DesktopDefault.aspx?PageID=535. Feng, X.Y. 1999. Studies on sesame germplasm resources in China. I. Collection, catalogue and classification [in Chinese]. Chinese Journal of Oil Crop Sciences 21(2): 77–80. Feng, X.Y. 2000. Studies on sesame germplasm resources in China. II. Conservation and regeneration [in Chinese]. Chinese Journal of Oil Crop Sciences 22(1): 43–45. Fukuda, Y., M. Nagate, T. Osawa and M. Namiki. 1986. Contribution of lignan analogues to antioxidative activity of refined unroasted sesame seed oil. Journal of the American Oil Chemists’ Society 63(8): 1027–1031. Huang, F.H. 2001. Sesame. In Special Oil Crops Processing and Comprehensive Uses [in Chinese]. 1–48. China Agricultural Science and Technology Press, Beijing. Huang, Z.Y., H.B. Wang and Z.W. Liu. 2004. Optimum extraction technology of flavonoids in sesame leaves. Transactions of the Chinese Society of Agricultural Engineering 20(6): 201–204. Laufer, B. 1919. Sesame and flax. Sino-Iranica. Field Museum of Natural History. Anthropological Series 15: 288–296. Li, L.L. 1989. The kinds of diseases and studies in sesame in China. Oil Crops of China (1): 11–16. [in Chinese] Li, Y.C., Q.Y. Guo and Y.Z. Zhao. 2005. The introduction of sesame cultivars. In The Guidance for Introduction of Rapeseed and Sesame Cultivars. 63–95. Jindun Publishing House, Beijing. [in Chinese] MAPRCSTAT. 2006. URL http://zzys.agri.gov.cn/nongqing.asp. Miao, G.Y., J. Yin, Y.T. Zhang and A.L. Zhang. 1998. Study on root growth of main crops in North China [in Chinese]. Acta Agronomica Sinica 24(1): 1–6. Mohamed, H.M.A. and I.I. Awatif. 1986. The use of sesame oil unsaponifiable matter as a natural antioxidant. Food Chemistry 62(3): 269–276. Peng, J. M. 1989. Practice and understanding of sesame irrigation [in Chinese]. In Proceedings of Second National Sesame Symposium, 132–139, Wuhan, China. Shen, J. X., Q.Y. Guo, X.R. Zhang, Y.Z. Zhao, X.Y. Feng, H.X. Chen and X.M. Wu. 1995. Cluster analysis of sesame germplasm collection in China. Journal of Huazhong Agricultural University 14(6): 532–536. [in Chinese] Wang, J.X., L. Song, X.J. You and G.L. Zhao. 2004 Studies on the chemical constituents of sesame [in Chinese]. Chinese Traditional and Herbal Drugs 35(7): 744, 802. Wang, A.J. 2004. The processing technique of sesame leaves for soft canned food. Agroproduct Processing (1): 20. [in Chinese] Xie, F.H. 1997. Study on industrial production of traditional pestle tea. China Western Cereals and Oils Technology 22(4): 40–41. [in Chinese] Xu, X.Z. 1996. Observation on clinical cure efficacy of walnut black sesame honey on 87 cases of weakness constipation. Journal of Wuhan University (Natural Science Edition) 42(6): 783–786. [in Chinese] Yan, X.C. and Y.Z. Zhao. 2001. Sesame. In Cultivation Techniques of Special Oil Crops for High Quality and Yield. 106–139. China Agricultural Science and Technology Press, Beijing. [in Chinese] Yang, Y.D., X.Y. Xue, X.L. Jin, X.S. Yang, L.M. Jin, X.Y. Zhang and B.C. Du. 1996. Occurrence and prevention of leaf spots in sesame. Henan Agricultural Sciences (6): 18–20. [in Chinese] Zhang, D.Q, J.X. Tai, Q. Fu. 1999. Survey on research and application of bioflavonoids. Food and Fermentation Industries 25(5): 52–57. [in Chinese] Zhang, X.R., Y.Z. Zhao, Y. Cheng, X.Y. Feng, Q.Y. Guo, M.D. Zhou and T. Hodgkin. 2000. Establishment of sesame germplasm core collection in China. Genetic Resources and Crop Evolution 47: 273–279. Zhang, Y. and C.H. Li. 1991. Integrated Cultivation Technique for High Yield in Sesame [in Chinese]. Scientific and Technical Documents Publishing House, Beijing.

Cultivation 18 Sesame and Use in Ethiopia Adefris Teklewold, Tadele Amde, and Tesfaye M. Baye Contents Introduction..................................................................................................................................... 298 Production and Primary Sesame-Growing Regions of Ethiopia..................................................... 298 Environments Suited for Sesame Cultivation................................................................................. 301 Crop Husbandry..............................................................................................................................302 Land Preparation........................................................................................................................302 Production Systems....................................................................................................................302 Planting Dates............................................................................................................................ 305 Method and Rate of Seeding...................................................................................................... 305 Fertilizer Application................................................................................................................. 305 Weed Control............................................................................................................................. 305 Irrigation.....................................................................................................................................306 Harvesting and Threshing..........................................................................................................306 Labor and Sesame Production....................................................................................................307 Cultivars/Varieties...........................................................................................................................308 Diseases and Pests........................................................................................................................... 310 Diseases...................................................................................................................................... 310 Insect Pests................................................................................................................................. 310 Production Cost and Marketing...................................................................................................... 311 Production Cost.......................................................................................................................... 311 Marketing................................................................................................................................... 311 Export Numbers......................................................................................................................... 313 Usage of Sesame............................................................................................................................. 314 Sesame Oil................................................................................................................................. 314 Foods Prepared with Sesame..................................................................................................... 315 Use in Magic.............................................................................................................................. 316 Livestock Feed........................................................................................................................... 316 Substitute for Wood.................................................................................................................... 317 Traditional Medicine.................................................................................................................. 317 Use as Shampoo......................................................................................................................... 317 References....................................................................................................................................... 318

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Introduction Ethiopia’s economy is primarily agricultural, accounting for half of the gross domestic product, 60% of exports, and 80% of total employment (CIA World Fact Book 2006). Crop production has the lion’s share of the agriculture sector. Among edible oilseeds, sesame (Sesamum indicum L.) stands second in terms of area and total production, after noug (Guizotia abyssinica Cass.) (Central Statistical Agency (CSA) 2008). Low productivity, poor crop management, low input, lack of improved technology, and ineffective extension systems characterize most crop production in Ethiopia. Sesame, called selit in Amharic and Tigrigna and sallet in Afan Oromo, is one of 15 cultivated oil crops in Ethiopia (Seegeler 1983). Requiring long, dry and sunny growing conditions with warm temperatures, sesame, with groundnut and safflower, is categorized as a lowland oil crop in Ethiopia (Hiruy 1991). Sesame is cultivated in most parts of the country by smallholder peasants and largescale farmers, mainly under rainfed conditions. It is cultivated in areas at an altitude between 500 and 1250 m that receive 500–700 mm rainfall and have a mean temperature of 23–28°C (Getinet et al. 1997). In 2005, sesame cultivation occupied 136,220 hectares (ha) of land, producing 115,364 metric tons (T) (CSA, 2005). Sesame is grown primarily as a cash crop in Ethiopia. Both large- and small-scale peasant farmers appreciate the good price sesame fetches on the domestic and international market: always a premium above the other oilseeds and field crops. Most of the sesame produced (60–70%) is exported (CSA 2003). Oilseeds contributed 15.25% and 12.85% of the total foreign exchange earned by Ethiopia in 2003 and 2004, respectively (Ethiopian Customs Office, unpublished data 2005). Recent production statistics indicate a steady increase in sesame production. There is reason to believe that its production will continue to grow as a result of its role in export diversification and foreign exchange earnings that help to create employment and income generation for a large number of farmers and others linked directly or indirectly with sesame production. While sesame has substantial economic advantage, its production is still largely traditional. Application of chemical fertilizer and other improved management practices are nil. Absence of economically appropriate production technologies has been a major constraint in sesame production. Considerable research has been devoted to sesame improvement and cultivation techniques, resulting in recommendations of improved varieties, cultivation practices, and plant protection measures. However, all this research effort has apparently brought little change in the actual productivity of sesame, owing to the lack of a effective strong, effective linkage between research and extension, unavailability of input supplies, especially seed, and lack of credit facilities. Seegeler (1983) thoroughly assessed many aspects related to sesame cultivation in Ethiopia. Since that publication, a substantial change has taken place in the research, production, and marketing of sesame.

Production and Primary Sesame-Growing Regions of Ethiopia Reliable production statistics are lacking for every agricultural crop grown in Ethiopia, because CSA estimates about acreage and production cover only private peasant holdings. For export crops such as sesame, the contribution of private commercial farmers is high, and so estimates of private peasant farms represent only part of the total amount produced in the country. For the same reason, in some years, data about sesame production obtained from the CSA indicate a lower quantity than the amount reported as exported by the Custom Office (see the Marketing section, below). But to show general trends, we present the CSA data here. Production statistics about sesame in Ethiopia show much inconsistency (Table 18.1). The area devoted to sesame cultivation was less than 100,000 ha in the 1960s. The figure increased in the 1970s, with about 165,000 ha cultivated in 1974 and 1975. This period coincides with the establishment of many private farms around Metemma and Humera. Compared to the 1960s and 1970s, sesame production shrank dramatically in the 1980s, reaching its lowest level, a mere 170 ha, in

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Table 18.1 Area , Production, and Yield of Sesame for Private Peasant Holdings in Ethiopia for the Period 1965–2005 Year

Area (1000 ha)

Production (1000 metric tons)

Yield (kg/ha)

Year

Area (1000 ha)

Production (1000 metric tons)

Yield (kg/ha)

65 66 67 68 69 70

82 96 95 97 97 97

32.80 37.44 37.05 39.77 39.77 39.77

400 390 390 410 410 410

85 86 87 88 89 90

— — 0.17 4.53 11.28 —

— — 0.03 0.55 4.07 —

— — 200 122 361 —

71 72 73 74 75 76 77 78 79 80 81 82 83 84 85

155 156 163 165 165 100 70 70 79 88 — — — — —

93.00 104.99 92.75 110.39 99.99 60.00 45.01 39.97 38.08 44.88 — — — — —

600 673 569 669 606 600 643 571 482 510 — — — — —

91 92 93 94 95 96 97 98 99 200 201 202 203 204 205

— — — — — 9.39 18.5 23.62 32.2 38.19 42.37 62.75 58.78 91.53 136.22

— — — — — 3.34 7.28 9.83 17.68 15.63 18.88 40.65 38.90 61.46 115.36

— — — — — 356 393 416 549 409 446 648 628 672 847

Source: 1965–1980 FAO Production Yearbook; CSA (Central Statistical Agency) 1996–2005; CSA 1987–1989. Note: For the years 1981–1986 and 1990–1995, a reliable estimate of area and production is lacking.

1987. During that period, the major sesame-producing areas, Metemma and Humera, were experiencing adverse insecurity. Recently, a revival in sesame cultivation has been observed, and production has been growing steadily since 1996. Sesame cultivation increased to a recent high of 136,000 ha in 2005 (CSA 1996–2005). The high price sesame fetches as an export crop is the single most important reason for the recent steady increase in area planted. Akin to total production, the productivity of sesame also shows inconsistency over the years. Seed yield varied from 122 kg/ha in 1988 to 847 kg/ha in 2005. Assuming that productivity statistics are reliable, variation in rainfall and shortage of labor are responsible for the fluctuation in productivity, beyond yield losses from the use of unimproved varieties, poor husbandry, diseases, and pests. Since sesame farmers obtain a rather attractive price now, they have become convinced to provide greater care for their crop. Ethiopia is composed of nine ethnic-based regional states and two city administrations (Figure 18.1). The agricultural census of 2003 (Table 18.2) indicates that all administrative regions— aside from Addis Ababa, which is located on the highland with few rural farm holdings—produce sesame, although nearly all of the sesame is grown in four states: Tigray, Amahara, Oromia, and Benishangul-Gumuz. Humera (western Tigray), Metemma (northwestern Amahara), Belles Valley (Benishangul-Gumuz) and East Wellega (western Oromia), where most sesame production is concentrated, may be viewed as Ethiopia’s sesame belt. Nevertheless, large areas of the Gibe Valley,

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TIGRAY REGION

14°

N

AMHARA REGION

E

W

AFAR REGION

S

12°

DIRE DAWA

BENISHANGUL GUMUZ REGION ADDIS ABABA

LEGEND

10°

NATIONAL BOUNDARY

HARARI

REGION BOUNDARY

GAMBELLA REGION

8° SOMALI REGION

OROMIA REGION

SOUTHERN REGION

6°

0

100

200

Kilometers

4°

34°

36°

38°

40°

42°

44°

46°

Figure 18.1  Map of Ethiopia. (From Ethiopian Institute of Agriculture Research, GIS unit 2006.)

Table 18.2 Estimates of Holder, Area, Production and Yield of Sesame in 2003 by Regional States Regional States Tigray Afar Amahara Oromia Somali Benishangul-Gumuz SNNP Gambella Harari Addis Ababa Diredaw

Number of Holders

Area (ha)

Production (T)

Yield (kg/ha)

35,507 592 84,350 54,443 52 39,907 2,928 1,113 192 — NRE

21,093.57 NRE 18,111.31 9,908.61 NRE 9,028.15 172.59 314.63 NRE — NRE

13,111.97 NRE 13,263.08 6,497.45 NRE 5,771.90 53.51 80.66 NRE — NRE

622 NRE 732 656 NRE 639   31 256 NRE — NRE

Source: CSA (Central Statistical Agency) 2003. Note: SNNP = Southern Nations, Nationalities and People; NRE = Estimates were not reliable because their coefficient of variation was > 50 %.

300

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Sesame Cultivation and Use in Ethiopia

Jinka plain, and the lowlands of northern Omo of southern and southwestern Ethiopia and the lower and middle Awash Valley of northeastern Ethiopia also grow sesame. Tigray holds the largest sesame cultivation area since it includes Humera, the most important traditional sesame-growing area, with deep-rooted sesame cultivation experience. About 36% of Ethiopia’s total area of production is located in Tigray. Amahara, Oromia, and Benishangul-Gumuz contribute 31%, 17%, and 15% of the total area of sesame production, respectively. In 2003, the average yield in Amahara was 10% higher than the national average. In Tigray the average land holding, 0.59 ha/farmer, was higher than any of the other regional states. The average farm size in Tigray is 2.8 times larger than Amahara (0.21 ha/farmer) and 3.3 times higher than Oromia (0.18 ha/farmer). Sesame being a sun- and warmth-loving crop, its ecological requirements are best meet in the Humera and Metemma areas. Agroecologically, these areas are classified as hot to semi-arid plain (Afera et al. 2002). The topography ranges from flat to undulating-flat but most of the large-scale sesame farms are located on the flat parts (Afera et al. 2002) that suit mechanization. The altitude ranges from 536 to 1862 m at Humera, and 549 to 1608 m at Metemma. These areas exhibit hot climatic conditions with a mean maximum temperature of 35°C, a mean minimum of 19°C, and mean average of 27°C. Humera, with a mean annual rainfall of about 668 mm, is drier than Metemma, which receives about 918 mm annually (pers. comm., Ethiopian Institute of Agriculture Research GIS unit 2007). Eutric Vertisol and Eutric Cambisol are the dominant soil types around Humera, and Haplic Luvisols and Humic Nitosol around Metemma (Ethiopian Institute of Agriculture Research GIS unit 2007). The Vertic soils give the advantage of moisture retention during dry years but have a physical workability problem.

Environments Suited for Sesame Cultivation Ethiopia has a wide, topographically determined climatic variation. Sesame-growing environments are classified as suitable, moderately suitable, and marginally suitable (Table  18.3), based on crop performance and seed yields observed in national and extension variety trials carried out in the diverse sesame-growing areas of the country. Most of the traditional sesame-growing areas in Ethiopia occur below 1250 m, and sesame grows very well between 500 and 1250 m. However, some genotypes are adapted to extremes as low as 300 m and as high as 2000 m. Sesame requires Table 18.3 Environmental Requirements for Sesame Suitability Range Weather and Soil Characteristics Altitude (m) Temperature (°C) Minimum Maximum Mean Rainfall Soils Type Texture Color pH

Highly Suitable

Moderately Suitable

Marginally Suitable

500–1250

350–500/1250–1600

90% to the top 14 importers. 8 of the top 14 importers import >90% from the top 16 exporters.

Note: Table cut offs: Importers $40M and Exporters $20M

World India Ethiopia Nigeria Paraguay Myanmar China Sudan Tanzania Mozambique Guatemala Burkina Faso Pakistan Venezuela Netherlands Mexico Uganda Other %

Exporters

Importers

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445

Current Market Trends

increasing roasting temperature and time between 160º and 200ºC, but color units of oils increased markedly higher than a 220ºC roasting temperature. There were significant decreases in the amounts of triacylglycerols and phospholipids in the oils roasted at 250ºC. The amounts of c-tocopherol and sesamin remained over 80% and 90%, respectively, of the original levels after roasting at 250ºC. Oil prepared using a 250ºC roasting temperature contained sesamol at 3370 mg per kg oil, but sesamolin nearly disappeared after 25 minutes of roasting. Burning and bitter tastes appeared in the oils prepared at roasting temperatures over 220ºC. Their results suggested that a high-quality product would be obtained by roasting for 25 minutes at 160º or 180ºC, 15 minutes at 200ºC, and 5 minutes at 220ºC, compared with the other choices. Toasted oil is preferred for East Asian cuisine, added after the cooking is complete to intensify flavor. To produce 1 liter of oil from toasted sesame seeds requires 3 kg (Teknologi Lemak & Minyak 2009).

Sesame Oil Value in World Trade: Gains with Processing Overall, during the past two decades, about 55% of sesame seed grown in world commerce is crushed for oil (Figure 25.7; FAOstats 1961–2007); during earlier years, the quantity reported to FAO was slightly higher, ca. 60%. The long-term trend is down. This may be because, increasingly, more sesame seeds are crushed for paste or used in confectionary. The world imports 866,079 tons of seed, paying $1,453,000,000, an average of $1680/T. The world imports 32,100 tons of sesame oil, paying $132,265,000, on average $4120/T. If one recovers 50% oil from seed, on a weight basis, that represents a 23% increase in value to convert seed to oil (4120/(1680*2)). Since we calculate that most seed (50–60% historically) is converted to oil, and the total cash value of imported sesame seed ($1.4 billion) is 10 times that for sesame oil imported ($0.132 billion), it would appear that most of the sesame seed imported is converted to oil for use in-country. The estimate would be 866,079 tons of seed imported, converting 53% (from graph) to oil (866,079*.53*.5 = 230,000 T of oil produced; 32,100 T were exported in 2008, reserving ~86% of sesame production for in-country use, on a world basis. Estimated % Sesame Seed Crushed for Oil (World)

70 60 50 40 % 30 20

% Seed to oil

Figure 25.7  Estimated % sesame seed crushed for oil (world), FAO.

2007

2005

2003

2001

1999

1997

1995

1993

1991

1989

1987

1985

1983

1981

1979

1977

1975

1973

1971

1969

1967

1965

1963

0

1961

10

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Value estimates indicate that crushing seeds to prepare sesame oil increases the original investment substantially. Sesame is an upscale commodity for Japan, similar to olive oil (Dyck 2000); in the years covered by that decade-old report, sesame prices rose, leading to lower sesame imports. The world’s largest sesame oil importers are (1) United States, (2) EU27, (3) Hong Kong, (4) China, (5) Malaysia, (6) Japan, (7) Canada, (8) Australia, (9) Mexico, (10) Singapore (Figure 25.8; ERS World Trade Atlas 2009). Japan, Mexico, Taiwan, and China led exports of sesame oil to the United States in 2008, with lesser quantities from Turkey, Lebanon, U.K., and India (ERS World Trade Atlas 2009). The price per ton of sesame oil nearly doubled between 2007 and 2008, nearly tripling the price of 2002. Expenditures by selected nations on sesame oil for 2003–2008 appear in Figure  25.9; major sesame oil trading partners in 2008 appear in Figure 25.10.

Sesame Commerce in Context with Other Edible Oilseeds The FAO and commercial interests classify sesame as a “minor crop.” This designation appears to be correct in terms of monetary value. FAOstats (2007) provide data about production, yield, and quantity of land under cultivation, as well as value and quantity produced. In 2007 India, while leading global sesame production, does not rank sesame in the top 20 crops in terms of value. In Myanmar sesame ranks 4th in value; in the Central African Republic, sesame ranks 5th; in Cambodia and Sudan, sesame ranks 8th in value; in Somalia, sesame ranks 9th; in Chad and Paraguay it ranks 10th; in Burkina 17th; among other top producers, including Bolivia, China, Egypt, Mozambique, Nigeria, Tanzania, Thailand, sesame does not rank in the top 20. The mode of production of sesame is highly significant compared with other grains. The World Trade Organization Committee on Agriculture Special Session’s brief review (2008) of sesame production in Paraguay is indicative. The agricultural sector in Paraguay comprises two types of production. The first consists of small producers (less than 20 ha), who follow traditional methods to produce crops for home consumption and/or one or more cash crops such as cotton, sugar cane, sesame, tomatoes, peppers, groundnuts, physic nuts, tobacco, fruit, and vegetables. The second is commercial farming, which uses medium- or high-level technology mainly to produce soya beans and cereals. Sesame is not often in this category, worldwide, except in the United States. Pitts et al. (2007) comprehensively, investigated the globalization of food production and consumption in the last half-century through the medium of fats and oils. In their view, the dual traits of being essential for human life and signifying a diverse range of regional styles of consumption make lipids an ideal bulk commodity to study international differences in food. They examined FAO data about dietary fats and oils from 1961 and 2003 using correspondence analysis, a means of displaying the principal trends in large tables of data. The analyses reveal evidence for a global convergence in lipid availability (from animal fats to vegetable oils) from 1961 to 2003, in addition to trends towards an increased disparity that at the extremes is between the wealthiest, as importers of diversity, and least affluent regions, as the areas most resistant to homogenizing trends. Their review, “Oil for Food,” found a reduced emphasis on animal fats and fish oils (in more wealthy regions, especially Australia and New Zealand, Northern Europe, and the U.K. and Ireland) and certain vegetable oils (in less affluent regions, particularly sesame, palm kernel, and groundnut oils in Central and South America), accompanied by a corresponding convergence on a small number of vegetable oils, especially soy bean, rape, and maize; the period of most rapid change appears to be from the mid-1970s to the late 1980s. A prominent feature is the split between patterns of lipid importation in 1961 and 2003. Although this pattern indicates a general shift in the importation of fats and oils since 1961, the nature of convergence appears to be towards an increased diversity in lipid intake, especially of vegetable oils (olive, coconut, palm, rice bran, palm kernel, rape, sesame, and sunflower oil). The main characteristics of this transition include a general global shift away from animal fats (with the exception of cream) towards vegetable oils. While affluent regions (Europe, North America, Japan, South Korea,

32,100 6,136 5,501 5,163 3,925 2,995 2,086 1,249 695 690 653 595 428 330 235 212 171 154 134 748 98

World China Mexico Japan Taiwan India Singapore Vietnam Malaysia United States Hong Kong Thailand France Turkey Lebanon UK Germany Indonesia South Korea Other %

10,489 1,072 2,788 3,937 1,781 134 7 0 0 0 29 51 1 236 176 142 2 0 29 104 99

U.S.

5,425 887 2,307 78 11 211 658 5 111 229 276 305 0 25 29 0 0 18 22 253 95

EU27 2,520 1,583 0 247 494 48 147 0 0 0 0 0 0 0 0 0 0 0 0 1 100

Hong Kong 1,835 10 38 102 778 760 6 0 0 10 0 0 0 0 0 0 0 131 0 0 100

China 1,438 825 0 1 78 122 319 0 0 10 21 0 0 0 0 0 0 0 33 29 98

Malaysia 1,428 96 104 657 180 9 21 0 9 197 87 0 29 1 3 1 5 0 9 20 99

Canada

Figure 25.8  Major sesame oil trading partners, quantity (metric tons), 2008, ERS.

Note: Subset cut offs are Imports >510, Exports >100

World

Exporters 1,421 109 2 0 7 0 40 1244 1 0 0 0 0 0 0 0 0 0 2 16 99

Japan

Importers

1,089 325 67 28 168 16 303 0 37 0 77 0 0 0 1 9 1 5 21 31 97

Australia 1,039 9 0 20 123 718 1 0 0 143 0 1 0 0 0 0 0 0 0 24 98

Mexico 1,021 363 83 17 91 95 0 0 363 0 1 0 0 0 0 0 0 0 3 5 100

Singapore 767 27 14 6 0 491 0 0 0 0 0 228 0 0 0 0 0 0 0 1 100

Taiwan 577 26 0 8 0 1 325 0 143 0 68 0 0 0 0 0 0 0 2 4 99

Indonesia

90 87 98 99 95 87 88 100 96 85 86 98 7 79 89 72 5 100 90

%

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448

Sesame: The Genus Sesamum Expenditure on Sesame Oil 2003–2008 (selected nations)

10,000,000 9,000,000 8,000,000 7,000,000

$ U.S.

6,000,000 5,000,000 4,000,000 3,000,000 2,000,000 1,000,000 0

2003

2004 Hong Kong China Mexico Taiwan

2005 Japan Indonesia

2006 Singapore Russia

2007 Malaysia S. Korea

2008 Brazil Sri Lanka

Figure 25.9  Expenditure on sesame oil, 2003–2008 (selected nations), ERS.

Australia, and New Zealand) closely converge on the cluster of vegetable oils, several poorer regions (e.g., Latin America, North and Central Africa, and the Middle East) shifted towards the importation of maize and soybean oil in the upper-right quadrant. The biggest changes apparently occurred in the mid-1980s. The main exceptions to this rich-poor split are less affluent regions in 2003 plotted on the edges of the wealthier cluster in the lower-right quadrant (especially parts of Asia and Africa), possibly indicating some localized trade in crops such as palm and sesame oil. “Oil for Food” elucidates meaningful regional variations in food consumption, especially compared to other bulk food commodities (e.g., cereals). Their results appear to confirm the notion that global dietary shifts reveal lines of inequality (citing McMichael 2001), both in terms of class and region. They quote Bauman (1998): “Globalization divides as much as it unites; it divides as it unites—the causes of division being identical with those which promote the uniformity of the globe.” If it is true that “food embodies history like no other substance” (McMichael 2001), then lipids can be seen to oil the regional machinations of such change over centuries and decades. In spite of the relatively crude resolution (using bulk commodity availability and imports per capita in lieu of figures concerning actual consumption), it has been demonstrated that edible lipids are particularly sensitive indicators of globalization processes.

Mali’s Inadequate Domestic Supply It is regrettable that much African-grown sesame does not reach the local population. BBC journalist Hicks (2008) reported an example from Mali of unfortunate consequences associated with its “infertility cooking oil.” As Mali is one of sub-Saharan Africa’s biggest cotton producers, cottonseed oil is the oil of choice for most cooks because it is much cheaper. Its use as cooking oil

Current Market Trends

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has sparked a health scare because many of the country’s oil factories lack the refining equipment to remove the toxin gossypol from cottonseed, a toxin responsible for azoospermia (an absence of sperm in the semen) and for interrupting the menstrual cycle and pregnancy, and that can also affect the liver and the heart. In March 2008, the government closed down more than 80 small-scale producers because many Malian families may risk becoming infertile. Badly refined cotton oil still seems to be making its way onto the market, with many thousands of gallons of it still for sale. There has been a public information campaign alerting people to the dangers. Hicks recommends the real solution, which is for Mali to start refining sunflower, sesame, and groundnut seeds to make cheap cooking oil at home without the dangers of cottonseed oil. But while cottonseed oil continues to sell for almost half the price of the imported cooking oils, most large families do not feel they have the luxury to demand a better choice.

Fair Trade: Nicaragua Solidarity Campaign Replaces Gloomy Coffee Future with Sesame Oil, Successfully The Nicaragua Solidarity Campaign (NSC) encouraged diversification from coffee, reporting (2002) that since the mid-1990s, the Juan Francisco Paz Silva Co-operative in Achuapa has been selling sesame oil to the Body Shop for use in its products. The Body Shop operates a community trade program in accordance with fair trade principles, and the price Achuapa farmers receive for their oil is proportional to their production costs. Since 1993, orders have leapt from 2 T to 72 T a year, indicating the success of the project for both sides. A reporter describes how selling to The Body Shop has brought benefits to the community: “Stories emerge of greedy middlemen back in the early 1990s; low market prices and scams by commercial credit organizations charging high interest; drought and need to pay taxes to travel to Granada to sell sesame there; times when the farmers were forced to trade sacks of sesame seeds for sacks of corn at a loss, so their families could eat; continual cycle of debt and survival; then the story of change that began with the setting up of a community co-operative shop in Achuapa, offering credit and basic grains at low prices. Ten years later, it has grown into a co-operative of 132 members who produce high-quality sesame oil for export to the Body Shop at fair trade prices. Fair Trade guarantees a better deal to ‘third world’ producers. “A mechanical press is enabling much higher levels of production, and the fair trade prices offered by the Body Shop have transformed the lives of farmers in the co-op. Not only can they get credit to invest in essential farming equipment, but the co-op also provides training, a shop, a natural health clinic for homeopathic treatment and a model farm that employs local people and experiments with organic farming and diversification.” The Body Shop (2009) reviews its achievements supporting Fair Trade cosmetics. During travels in the 1980s, the late Anita Roddick, founder of The Body Shop, learned that many of the communities she visited were not getting fair pay for their ingredients or goods—often not enough to cover the cost of production or wages. Inspired by the early fair-trade movement happening with coffee and tea, Roddick started a Community Trade program, working with undeveloped countries that were otherwise powerless in securing a fair price for their products. Twenty-one years later, The Body Shop spends more than $12 million buying ingredients and accessories from suppliers in more than 20 countries. DeMaio (2009) summarized Nicaragua’s continued success with sesame for the Poverty Blog. One of those suppliers is a cooperative of sesame farmers in Achuapa, a village in Nicaragua. When Roddick met the farmers in the 1990s, they were struggling to make a living by exporting sesame oil. Roddick worked out a fair price for the sesame oil (now used in more than 40 Body Shop products, including the Moringa Milk Body Lotion) by calculating how much it costs to grow, as well as the community needs: cost of living, cost of education, etc. Body Shop then gave the farmers a forecast that projected how much sesame oil the company would purchase over the course of a year, giving the farmers a newfound sense of stability and the ability to invest in their community.

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Community Traded sesame oil is sourced from a co-operative of small-scale farmers in a remote area of Nicaragua. Since this relationship began, the co-op has built eight primary schools that educate 400 children, and it is currently building a boarding house in Achuapa so 40 children can attend secondary school. Other improvements include 13 sanitary water wells, an acupuncture and natural medicine clinic, a bank that offers low-interest loans and encourages community members to save money, a model farm to test organic farming methods, and family workshops to educate the community on social issues, such as gender equality and domestic violence. Since the late 1980s, The Body Shop has been developing fair trade relationships with local communities, often in remote areas, that do not usually have the chance to sell their products to global companies. It buys natural ingredients such as cocoa beans, sesame oil, and shea butter from them at a fair price. There are more than one hundred products containing Community Trade ingredients, including several long-standing products. Of the almost twenty Community Trade ingredients, the most popular are cocoa butter, soy oil, shea butter, sesame oil, and marula oil, which are each in more than 25 products. Africa Spa Cocoa Body Balm contains four fair trade items: cocoa butter, shea butter, beeswax, and sesame oil. Note, however, that sesame is not a new crop in Nicaragua. Winters (1964) commented on its agricultural diversification, about the normally consistent exports of coffee and cotton since 1951, and that sesame, and cattle and meat, timber, and sugar each yielded over a million dollars in foreign exchange during the years 1957 and 1958.

Fair Trade: Mozambique CLUSA Mozambique (2009) assisted IKURU (the Producer Owned Trading Company) to prepare for Fair Trade certification through CLUSA’s links with Twin Trading, a purchaser of Fair Trade produce based in the U.K. IKURU received certification for groundnut and cashew in 2006. In January 2008 IKURU expanded the scope of its program by achieving certification to sell Fair Trade sesame. IKURU’s producers are also certified by ECOCERT, to market organic sesame and groundnuts.

Value-Added Products Value-added agriculture refers to particular production processes that increase the economic value of an agricultural commodity, e.g., organic produce and otherwise enhanced products that increase consumer appeal and for which buyers are willing to pay a price higher than for undifferentiated products. This concept is a means for farmers in LDCs to add value to the raw seeds they grow domestically, rather than permitting those profits to pass into the hands of middlemen who import raw seed and re-export finished goods. Value-added agriculture is a significant rural income-inequity improvement strategy; value-added projects have created new jobs in some rural areas, so that LDCs capture a larger share of the consumer food dollar. The superiority of value creation with value-added products, such as sesame oil and meal (Amanor-Boadu 2003; Cowen 2002; Fleming 2005; Hardesty 1992; Short 2007), represents a shift from commodity agriculture to product agriculture, and captures more of a commodity’s value at the site of primary production. It can increase farmers’ incomes and profits for farm-related businesses. The prices of raw sesame seeds are much lower than its oil. Private entrepreneurs might establish sesame oil extraction plants in-country to ensure that a larger portion of the crop exported is in its higher, value-added form. Over a decade ago, Small-scale Rural Oilseed Processing in Africa (1998) encouraged Africans to process their domestic product locally. Researchers and development specialists working with Appropriate Technology International developed a method for introducing small-scale oil expelling enterprises to rural areas in Africa. A typical arrangement consists of a ram press for extracting the oil, a filtration device, maintenance tools, training, support, and information on proper use of the oil and residual cake, and the socioeconomic and nutritional benefits of an oilseed processing

$132,264,874 $48,859,366 $9,016,846 $8,687,689 $7,737,585 $6,937,956 $5,926,786 $5,178,494 $4,515,760 $3,859,070 $3,332,435 $3,218,942 $2,728,138 $2,259,556 $2,157,947 $1,810,301 $1,641,304 $14,396,699 89

World

29,824,192 23,466,754 244,825 1,640,373 147,717 2,738,981 448,494 40,420 190,054 28,325 52,361 65,639 9,667 0 25,293 94,706 50,092 580,491 98

Japan 20,045,785 9,988,776 912,983 0 2,706,497 0 131,694 434,419 232,410 1,938,176 257,444 2,860,918 0 0 0 0 0 582,468 97

Mexico 17,567,497 2,024,494 5,199,456 0 689,846 63,555 2,671,868 1,836,539 206,974 21,538 859,846 0 475,336 1,206,025 379,073 53,349 157,629 1,721,969 90

Malaysia 16,081,772 7,578,788 337,124 1,506,843 36,061 1,051,315 1,939,638 39,876 681,452 39,744 527,748 29,734 644 35,751 907,020 354,328 73,455 942,251 94

Taiwan

Figure 25.10  Major sesame oil trading partners, value (US$), 2008, ERS.

Note: Cutoffs of US$1M for Importers and US$2M for Exporters

World United States Netherlands Hong Kong UK Canada China Brazil Australia France Singapore Germany Indonesia Japan Philippines Mexico South Korea Other %

Importers 13,388,453 1,147,780 48,616 5,076,277 590,150 59,988 0 3,060 969,127 476,155 1,488,596 44,265 27,762 482,788 6,523 30,910 1,264,319 1,672,137 88

China

Exporters

10,627,415 24,237 1,085,085 454,723 1,515,515 141,317 2,025 0 1,787,972 1,216,995 0 58,037 2,079,537 238,429 488,849 0 1,290 1,533,404 86

Singapore 7,786,553 2,276,152 0 8,019 0 121,801 7,183 2,820,169 154,697 0 39,715 0 0 48,528 17,026 118,736 17,983 2,156,544 72

EU27 4,851,555 101,031 461,539 0 1,548,011 383,913 137,030 0 204,023 49,319 74,954 8,695 128,975 0 325,184 0 64,738 1,364,143 72

Hong Kong 3,948,677 0 554,310 0 20,304 2,335,993 0 3,818 32,927 5,366 0 13,647 0 0 0 258,150 11,798 712,364 82

U.S.

3,853,986 331,210 95,646 0 178,024 19,643 556,276 0 18,482 57,069 30,322 59,372 0 553 226 900,121 0 1,607,042 58

India

97 96 99 100 96 100 99 100 99 99 100 98 100 89 100 100 100

%

Current Market Trends 451

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Sesame: The Genus Sesamum

enterprise. The ram press, driven manually by a long handle, consists of a small piston that presses a measured load of oilseeds into a metal cage. The design was crafted in Tanzania in 1985. The original and improved versions are now widely used there and in other African countries. The press’s design has been continuously refined over the years, so that the original, large, two-man machine has evolved into a smaller, less expensive model operable by a woman. ATI has been particularly innovative in promoting commercialization of small-scale oil processing in Africa with its Regional OILS program, enabling producers to make the transition from dealing in low-return, raw commodities to value-added products. ATI has made a conscious effort to move from providing technical assistance for NGOs involved in small-scale oilseed processing to a private sector approach that emphasizes commercialization and mass manufacturing of ram presses. Shepherd (2007) shows that many linkage projects, particularly those with a “pro-poor” orientation, try to go beyond the immediate goal of improving rural incomes to that of enabling rural producers to become “chain owners”; farmers are not just suppliers of raw materials, but also manage the marketing or “value” chain up to the level of the consumer. This may involve farmers becoming involved in a range of value-adding activities, including preparation and processing, storage, transport, and sometimes retail sale. The SeneGambia Development Assistance Program (DAP) (2002–2007) indicates that various groups in Senegal and The Gambia have started the process of assessing the potential of selling sesame as well as sesame products, such as soap, oil, and crafts made out of the sesame plant stalk.

Part II—New International Partners, Globalization of Agriculture, Scramble for Land: Matters of Concern for Sesame Farming Critical emerging events in 2009 have received scrutiny by the FAO, the International Fund for Agricultural Development (IFAD), and the International Institute for Environment and Development (IIED). “Land grab” investments by rising powers and rich nations in countries that are poor or lack food security raise political and economic concerns, because the output favors the investing countries. Planning for such deals must instead aim to boost benefits to host populations, increase food security, and reduce poverty. There are reports of impending impacts upon existing sesame market trends, directly and substantially. The subject, while in its infancy, will likely escalate throughout this century and deserves sophisticated analysis. The FAO publication “Land Grab or Development Opportunity? Agricultural Investment and International Land Deals in Africa” spells out the details (Cotula et al. 2009): “Over the past 12 months, large-scale acquisitions of farmland in Africa, Latin America, Central Asia and Southeast Asia have made headlines in a flurry of media reports across the world. Lands that only a short time ago seemed [to attract] little outside interest, are now sought by international investors to the tune of hundreds of thousands of hectares. Governments concerned about stability of food supplies are promoting acquisition of farmland in foreign countries as an alternative to purchasing food from international markets. Recipient countries, welcoming the new wave of foreign investment, are implementing policy and legislative reforms to attract investors.” Food security concerns, biofuels, rising agricultural commodity prices, and policy reforms have improved their attractiveness. Two themes for the FAO World Summit on Food Security (2009) are relevant: (1) Africa’s food challenge: Prospects are good, resources are abundant; policy must improve. (2) Increased investment in agricultural research is essential: Producing more food will largely depend on increasing crop yields, not farming more land. The challenge is to promote this without harming peasant agriculture. The FAO-sponsored Expert Meeting “How to Feed the World in 2050” summary report, “International Investments in Agricultural Production” (Hallam 2009), makes known the recent resurgence of interest in international investment in agricultural land in Africa by investors from various Gulf States for food production. Countries outside Africa are also targets. “Dependence on

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world markets for foods supplies or agricultural raw materials has become more risky. Investment in food production overseas is one possible strategic response. At the same time, a number of developing countries in Africa are making strenuous efforts to attract such investments to exploit ‘surplus’ land, encouraging international access to land resources whose ownership and control in the past have typically been entirely national. Not surprisingly, the apparently anomalous situation of food insecure, least developed countries in Africa selling their land assets to rich countries to produce food that will be repatriated to feed their own wealthier people, has attracted substantial media interest.” International Food Policy Research Institute (IFPRI) head Joachim von Braun co-authored a policy brief with R. Meinzen-Dick (2009), “‘Land Grabbing’ by Foreign Investors in Developing Countries: Risks and Opportunities”: “One of the lingering price crises of 2007–08 on the world food system is the proliferating acquisition of farmland in developing countries by other countries seeking to ensure their food supplies … Increased pressures on natural resources, water scarcity, export restrictions imposed by major producers when food prices were high and growing distrust in the functioning of regional and global markets have pushed countries short in land and water to find alternative means of producing food. These land acquisitions have the potential to inject much needed investment into agriculture and rural areas in poor developing countries, but they also raise concerns about the impacts on poor local people, who risk losing access to and control over land on which they depend. “Rising effects of the food-importing countries with land and water constraints but rich in capital, such as the Gulf States, are at the forefront of new investments in farmland abroad; countries with large populations and food security concerns such as China, South Korea and India are seeking opportunities to produce food overseas. These investments are targeted toward developing countries, where production costs are much lower and where land and water are more abundant. Other factors that influence investments include geographic proximity and climatic conditions for preferred staple crops. “Although additional investments in agriculture in developing countries by the private and the public sector should be welcome in principle, the scale, the terms, and the speed of land acquisition have provoked opposition in some target countries. According to news reports, the Philippines blocked a land contract with China because of serious concerns about its terms and legal validity, as well as about its impact on local food security. Mozambicans have resisted the settlement of thousands of Chinese agricultural workers on leased lands—a situation that would limit the involvement of local labor in the new agricultural investments.” Von Braun and Meinzen-Dick (2009) propose a Code of Conduct, a dual approach to help address the threats and tap the opportunities related to foreign direct investment in agricultural land: 1) Threats must be controlled through a code of conduct for host governments and foreign investors. 2) Appropriate policies must facilitate opportunities in the countries that are the target of these foreign investments. Key elements for foreign land acquisition include transparency in negotiations; respect for existing land rights, including customary and common property rights; sharing of benefits; environmental sustainability; and adherence to national trade policies. When national food security is at risk (for instance, in case of an acute drought), domestic supplies should have priority. Foreign investors should not have a right to export during an acute national food crisis.

Journalist-Watchdogs Link “Land Grabs” to Population Explosion, Food, and Water Scarcity New Scientist writer Mackenzie (2008) offered a thorough summary of the debates with stern warning against rich countries snapping up land in Africa and elsewhere: “International land grab sparks food war fears. In some of the world’s poorest countries, where people are starving, rich nations and companies are buying up farmland to grow food and fuel for themselves and their paying customer. As demand for food grows, those who have the necessary funds are snapping up vast swathes of

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land to ensure their own security … The wars over oil of the recent past will pale in comparison to the global struggle for food that could result from the land grabs going on now. The land grabs have sparked accusations of neocolonialism and fears that the practice could worsen poverty. A number of companies are growing sugar cane in Tanzania, for example, to make bioethanol for European countries to meet European Union targets.” This year, investors from Gulf States initiated so many farm projects in Africa and Southeast Asia that the FAO urged care to avert a political backlash. According to Joachim von Braun, head of IFPRI, Egypt is investing in Sudan, Libya in Ukraine, Saudi Arabia in Thailand, and China in Africa, the Philippines, and Russia. As population growth and dwindling oil supplies make farmland the strategic resource that oilfields are now, the hunger for land appears likely to increase. China has 20% of the world’s people and only 9% of the farmland, and that is dwindling. A detailed analysis by the NGO Grain suggests that Chinese companies and the government have leased or purchased 2 million hectares of foreign farmland since 2007. Financial firms, too, are moving money from food to the land that produces it. Foreign deals pledge to turn “unused” or “underutilized” land into farmland to yield food. But is that land really unused? “Africa still has lots,” says Peter Hartmann, head of the International Institute for Tropical Agriculture in Ibadan, Nigeria. He says for every hectare of African farmland there are around 2.5 hectares of “equivalent rainfed arable land” unused for want of technology or capital. “But seemingly unoccupied land is probably used for at least part of the year by someone,” says Michael Taylor of the International Land Coalition (ILC), an aggregate of 65 agencies, from local farm groups to the World Bank, concerned with land access. “Nomadic herders, rarely a priority for governments, are being dispossessed by bioethanol developments in Kenya,” he says, and they depend on the “unused” land that Madagascar offered Daewoo. Ethiopia’s communal lands, such as grazing areas, are being leased to private investors, according to anthropologist Marco Bassi, University of Oxford. “This will destroy shifting cultivators and pastoralists.” In many cases, such people use the land because its soil or water is unsuitable for intensive cultivation. The danger then is that foreign leaseholders might extract what they can from these areas, and then leave once soil and water resources are exhausted. Some people see upsides, though. “I could imagine such land use benefiting people,” says Hartmann. Foreign investors build roads and storage and port facilities that local farmers can also use to sell crops—a bottleneck in much of African agriculture. “Such investments are not to be generally condemned,” says von Braun. Leaseholders might press for better tax situations for farmers, while host countries could insist on local hiring. “The best option would be for foreign firms to contract local small farmers to grow crops for them,” says Paul Mathieu of the FAO. “Investors could say, if you use this seed and follow our advice we promise to buy the crop. That could be a win-win situation.” German company Flora Eco Power produces biodiesel in Ethiopia in this way. Hartmann and von Braun say a code of conduct must include provisions for local producers, property rights, sustainable management, and transparent rules. The FAO is now trying to write such guidelines. Stacy Feldman (2009) weighed the African land-grab deals in an analysis of the IFPRI study: “Despite widespread research indicating that growing biofuels on Africa’s ‘idle’ lands could help to starve the continent, the practice remains rampant. Much of that land is bought by emerging nations to raise crops for their growing populations. These countries—China, India, South Korea, and oilrich Gulf states—have land and water constraints at home. They got burned by last year’s global food crisis and are turning to Africa as a food security blanket.” Critic Gwynne Dyer (2009) expounds: “In the past two years, various non-African countries— China, India, South Korea, Britain and the Arab Gulf states lead the pack—have been taking over huge tracts of farmland in Africa by lease or purchase. This is to produce food or biofuels for their own use … The scale of the land grab is truly impressive. In Sudan, South Korea has acquired 690,000 hectares of land to grow wheat. The United Arab Emirates, which already has 30,000

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hectares in Sudan, is investing in another 378,000 hectares to grow corn, alfalfa, wheat, potatoes, and beans. In Tanzania, Saudi Arabia is seeking 500,000 hectares. “Only rarely is there protest from local people. One striking exception is in Madagascar, where the announcement of a 99-year contract to lease 1.3 million hectares to South Korea’s Daewoo Corporation to grow corn helped to trigger the recent revolution. ‘Madagascar’s land is neither for sale nor for rent,’ said the new leader, Andry Rajoelina, who cancelled the deal. “After the revolution, it turned out that another 465,000 hectares of land in Madagascar had been leased to an Indian company, Varun International, to grow rice for consumption in India.” That deal is also being cancelled by the new government—but elsewhere, the acquisition of huge tracts of African land by Asian and European governments and companies goes ahead almost unopposed. John Parker (2009), globalization correspondent for The Economist, evaluates: “Rich food importers are acquiring vast tracts of poor countries’ farmland. Is this beneficial foreign investment or neocolonialism? … A group of Saudi investors is spending $100m to raise wheat, barley and rice on land leased to them by the government. The investors are exempt from tax in the first few years and may export the entire crop back home. Meanwhile, the World Food Program (WFP) is spending almost the same amount as the investors ($116m) providing 230,000 T of food aid between 2007 and 2011 to the 4.6m Ethiopians threatened by hunger. Water shortages have provided the hidden impulse behind many land deals.” Peter Brabeck-Letmathe, the chairman of Nestlé, claims: “The purchases weren’t about land, but water. For with the land comes the right to withdraw the water linked to it, in most countries essentially a freebie that increasingly could be the most valuable part of the deal.” He calls it “the great water grab.” Lorenz and Thielke (2007) showed how Africa is feeding China’s hunger for raw materials: “China is conquering Africa as it becomes the preferred trading partner of the continent’s dictators. Beijing is buying up Africa’s abundant natural resources and providing it with needed cash and cheaply produced consumer goods in return.” China imports everything the continent produces: tropical hardwoods, oil, metals, and even a small amount of cotton. Africa’s five most resourcerich countries—Angola, South Africa, Sudan, Equatorial Guinea, and Congo—account for more than 80% of all African exports to China. In return, Africa gets cheap, mass-produced items, basic consumer goods such as household devices, television sets, and clothing. From South African supermarket shelves to Uganda’s flea markets, the products with the strange characters printed on their packaging are available everywhere. In fact, the flood of cheap Chinese goods has already destroyed the textile industries in Swaziland and Lesotho. BBC reporter Bristow (2007) worried about China’s out-migration to Africa. “They are part of China’s bid to secure raw materials and markets for its manufactured goods, but they are also carving out their own opportunities.” Quoting the head of China’s Export-Import Bank, Li Ruogu urged Chinese farmers to move to Africa, where there is plenty of land, but a food output that is not up to expectations. Smith complains in “The Food Rush” (2009): “Some of the world’s richest countries are buying or leasing land in some of the world’s poorest to satisfy insatiable appetites for food and fuel. In the new scramble for Africa, nearly 2.5 million hectares (6.2m acres) of farmland in five sub-Saharan countries have been bought or rented in the past five years, at a total cost of $920m. “A recent report by IFAD, FAO, and IIED described the huge deals reported to date as ‘the tip of the iceberg.’ Farmland purchases are driven by food security concerns, rising demand and changing dietary habits, expanded biofuel production and interest in what is, in theory, an improved investment climate in some African countries. In fact, China, well known for its interests in minerals and oil, appears to be one of the more modest ‘neocolonialists’ of African agriculture. Companies from India, South Korea, America and several oil-rich, food-poor Arab nations are buying vast tracts of the continent’s arable but fallow land. “Quoting Lorenzo Cotula, senior researcher at the IIED, ‘The role of China needs a more subtle analysis. We found that in Africa, China is not one of the big players in terms of acquiring large tracts of land. There is South Korea, there are Gulf-based countries, and there are also western

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institutions.’ Wealthy corporations have pioneered controversial African mega-farms to outsource food production and use cheaper labour. In India, such mega-farms are seen as more efficient than the traditionally small, family-run holdings throughout the country. Indian farming companies, backed by government loans, have bought hundreds of thousands of hectares in Ethiopia, Kenya, Madagascar, Senegal and Mozambique, where they are growing rice, sugar cane, maize and lentils to feed their domestic market … “In Ethiopia alone, the report found, India invested $4bn in agriculture, including flower-growing and sugar estates; the UAE secured 5,000 hectares for tea in a joint venture with East Africa agribusiness; Germany’s Flora EcoPower secured 13,000 hectares for biofuel crops; Britain’s Sun Biofuels secured land for jatropha, a biofuel crop; and unknown Saudi investors leased land in exchange for $100m in investment … “Sudan has also been a prime target: Egypt secured land to grow 2m T of wheat annually; Jordan secured 25,000 hectares for livestock and crops; Kuwait secured a ‘giant’ strategic partnership; Qatar set up a joint holding company to invest in agriculture; Saudi Arabia leased 10,000 ha for wheat, vegetables, and livestock; South Korea secured 690,000 ha for wheat; and the UAE is investing in 378,000 hectares after already securing 30,000 for corn, alfalfa, and possibly wheat, potatoes and beans. “Critics complain that countries are selling their land assets at the expense of subsistence farmers and hungry populations. The institute’s report cautioned: ‘Unequal power relations in the land acquisition deals can put the livelihoods of the poor at risk. Since the state often formally owns the land, the poor run the risk of being pushed off the plot in favor of the investor, without consultation or compensation.’” Rubenstein (2009) spoke out: “China’s growing appetite for African resources over the last decade is well documented. Indeed, China’s massive industrial machine relies on oil from Angola, Sudan, and Nigeria, and minerals from South Africa, Zambia, and Liberia.” While some commentators have already labeled China’s agricultural investment in Africa as self-serving, Chinese leaders are adamant that their actions are being misrepresented. Is China’s investment in African agriculture primarily self-interested? In order to better determine the nature and intention of China’s food policy in Africa, it is necessary to examine the details and context of China’s agricultural investment in Africa thus far. The Chinese are 1.3 billion people. But with only 7% of the world’s arable land, and the loss of over a million hectares of arable land annually to pollution and desertification, China’s interest in Africa increased considerably as China found an accessible source of oil and other raw materials with which to feed its rapidly growing economy. Between 1995 and 2005, China provided at least US$12.5 billion in aid to Africa, canceled billions of dollars in debt, and constructed new roads, schools, government buildings, stadiums and hospitals across the continent. In return, Africa now supplies a third of China’s oil. “China has indeed begun to put down substantial agricultural roots on the African continent. China’s investment in Mozambique illustrates both its commitment to the agricultural sector and the diversity of Chinese investment in Africa. Through a series of agreements, China has pledged $800 million to modernize Mozambique’s agricultural infrastructure and has financed the building of a dam and canal to bring water to arable land. Additionally, at least 100 Chinese agricultural experts are stationed in several research stations within Mozambique, working with local groups to increase crop yield and otherwise improve the performance of the agricultural sector. “Compounding suspicions of China’s intentions is the fact that although rice is not a significant part of the typical diet in Mozambique, China is pouring considerable resources into increasing output of rice, a staple of the Chinese diet. To some, the implications are clear: China first and foremost seeks to secure as much rice crop as it can from Mozambique’s farmland, and will advantage its own firms and workforce at the expense of those in Mozambique. “Given this stark assessment, many see China’s agricultural investments in Africa as nothing more than a grab for cheap, underutilized land. Jacques Diouf, director of the UN’s Food and Agricultural Organization, has gone so far as to specifically label this type of aggressive land-

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leasing as ‘neo-colonialism.’ The Chinese, however, protest at being labeled as exploitative and have played down the notion that their activity in Africa is self-interested.” Rice (2009) raised concerns in an essay provocatively titled “Is There Such a Thing as AgroImperialism?” Rice retraced the steps of Robert Zeigler, head of the International Rice Research Institute, in his visit to Saudi Arabia. Saudi leaders were frightened: heavily dependent on imports, they had seen the price of rice and wheat, their dietary staples, fluctuate violently on the world market over the previous three years, at one point doubling in just a few months. The Saudis, rich in oil money but poor in arable land, were groping for a strategy to ensure that they could continue to meet the appetites of a growing population. Zeigler went to Saudi Arabia hoping that the wealthy kingdom might offer money for the basic research that leads to such technological breakthroughs. Instead, to his surprise, he discovered that the Saudis wanted to attack the problem from the opposite direction. They were looking for land. In a series of meetings, Saudi government officials, bankers and agribusiness executives told an institute delegation led by Zeigler that they intended to spend billions of dollars to establish plantations to produce rice and other staple crops in African nations such as Mali, Senegal, Sudan, and Ethiopia. He was flabbergasted, not only by the scale of the projects but also by the audacity of their setting. Africa, the world’s most famished continent, cannot currently feed itself, let alone foreign markets. A variety of factors—some transitory, such as the spike in food prices, and others intractable, such as global population growth and water scarcity—have created a market for farmland, as rich but resource-deprived nations in the Middle East, Asia, and elsewhere seek to outsource their food production to places where fields are cheap and abundant. Foreign investors—some of them representing governments, some of them private interests— promising to construct infrastructure, bring new technologies, create jobs, and boost the productivity of underused land so that it feeds not only overseas markets but also more malnourished Africans. They have found that impoverished governments are often very welcoming, offering land at bargain prices. Investors who are taking part in the land rush say they are confronting a primal fear, a situation in which food is unavailable at any price. Throughout Africa, the politics of land is linked to the grim reality of hunger (Rice 2009). Every country has its unique dynamics. Rice reminds readers that Ethiopia was never colonized in the 19th century, but was ruled by an emperor instead, who granted feudal plantations to members of their royal courts. The last emperor, Haile Selassie, was brought down by a famine that fueled a popular uprising. The following governments, Marxist and thereafter, have maintained property rights to the land; farmers do not own land. McCrummen (2009) asks whether Africa is selling out its farmers as wealthy nations flock to farmland in Ethiopia, locking in food supplies grown half a world away, noting that governments across Africa are leasing land to foreign investors who use it to grow food to compensate for their own deficit, or for export. Increasingly, purely profit-seeking companies are snatching up land, making a simple, if somewhat grim, calculation. As “the population of the world is increasing dramatically, so land and food supplies will be short, demand will be higher and prices will rise.” Quoting David Hallam, a deputy director at the FAO: “These contracts are pretty thin; no safeguards are being introduced … You see statements from ministers where they’re basically promising everything with no controls, no conditions.” The harshest critics of the practice conjure images of poor Africans starving as food is hauled off to rich countries. Some express concern that decades of industrial farming will leave good land spoiled even as local populations surge. “Ethiopia’s farmland is in high demand. Desperate for foreign currency, the government has set aside more than 6 million acres for agribusiness. Lured with 40-year leases and tax holidays, investors are going on farm shopping sprees, crisscrossing the country on chartered flights to pick out their swaths of Ethiopian soil—especially Indian companies, which have committed $4.2 billion so far.” Anand Seth, director general of the Federation of Indian Export Organizations, described Africa as “the next big thing” in investment opportunities and markets. Corn has replaced Ethiopia’s staple cereal teff on many Indian-controlled farms.

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21st-Century Dilemma for Impoverished Sesame Growers in Ethiopia Reuters correspondent Tadesse (2009) reported: “Ethiopia has marked out 1.6 million hectares of land for investors willing to develop commercial farms. Gulf and East Asian companies have rushed to buy up farmland to secure food supplies .... ‘The government has verified and delineated 1.6 million hectares of virgin land suitable for large-scale commercial farming in different parts of the country,’ Esayas Kebede, Director of the recently formed Agricultural Investment Support, told Reuters. Some 8,420 foreign and local investors have already received licenses for commercial farms, but only 2,000 of them are known to have started work on their projects. ‘The contribution to the country’s economy, of those companies which began work is yet to be quantified …,’ he said. “Foreign firms that have started large scale commercial farming include Indian companies in sugar cane, tea and cotton production, a Saudi Arabian company in palm oil plantation and Chinese companies in sesame seeds. Esayas said … The government considered inviting those with technological knowledge and finances to develop its resources as an effective way to eliminate hunger and poverty. ‘Production in quality and quantity of food and other exportable commodities are our topmost priority,’ he said. “The land set aside was in Benishangul-Gumuz and Gambella in western Ethiopia, in the Southern Nations, Nationalities and People’s Region, and in Afar. The land can grow coffee, cotton, sesame, soya beans, forage crops, sugar cane, palm oil, and horticulture … A further 800,000 hectares in the Oromia region and 300,000 in the Amhara region were also allotted for commercial farming. He said the government offered incentives, like financing, to those willing to start commercial farms in Ethiopia. ‘Investors who qualify have the opportunity to receive loans from local banks up to 70% of their capital investment as well as attractive incentives and tax holidays, he said’” An official with knowledge of the case fears that consequences of allowing Chinese to lease or purchase Ethiopian land for sesame cultivation are that sesame prices may be driven down, indigenous farmers may lose their livelihoods, virgin lands may become contaminated, and Chinese workers may displace Ethiopian indigenous farmers. The Ethiopian government is lauding the likely future success of such endeavors without taking into account the unpreparedness of Ethiopia’s small-scale agricultural producers to compete with China or any other investor country in the production and marketing of their products, especially sesame. Ethiopia has risen to be the world’s fourth largest producer of sesame, albeit with low-input agricultural technology. There are fears that Ethiopia may not be competitive with China in terms of capacity to bring their produce to market, as a result of inefficiencies in its export trade. Other fears include potential threat to local employment, if the Chinese bring their own workers, including cooks and cleaners; such a case would not be profitable for local residents. Ideally, Ethiopians themselves should execute the entire process, from cultivation to marketing. Demisse (2009) reflected on Ethiopia’s strengthening oilseeds sector in the Ethiopian Reporter, warning of the risk of monocropping in the case of sesame. “The growing demand in the world market for these specialty products and the available capacity to expand production could turn oilseeds into one of the engines of economic growth of Ethiopia. Recently, China has been unable to produce enough sesame seeds to meet its own demand. This has led to a strong increase in Ethiopian sesame seed exports to China in the past two years.” Ethiopia is the main supplier of sesame seeds to Israel, supplying about two-thirds of its needs; to the Turkish market, the Ethiopian share is ca. 20%. In the past few years, Ethiopia has gained a market share in the Middle East (especially Yemen) at the expense of Sudan. Because of quality problems in the past, Ethiopia had not been an important exporter to Japan, despite the fact that it was the world’s largest importer of sesame seed. However, it seems that the volume of Ethiopian oilseeds exported to Japan is increasing via China. It seems unlikely that these are empty lands. The fertility of these regions must still be determined; if they are not sufficiently fertile to raise crops, transhumant populations surely use them for herding. From a genetic resources point of view, the introduction of new Chinese cultivars are likely to displace local Ethiopian landraces as farmers are instructed to replace indigenous cultivars

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with supposed “improved” cultivars. It will advance the disappearance of traditional life ways, as farmers serve the corporate interests of commercial farms. Some fear that competition with Chinese sesame will drive the price down. Informed sources familiar with the situation affirm that the government, in need of foreign currency, has long sought external capital development of “underused” lands. It is greatly enamored of high-tech solutions, not least in agriculture. The investors are Chinese, Indian, Indonesian, and Saudi. Indians were offered a huge land area around Gambella for oil palm production, and they have already begun preparations. The Saudis also got the green light for half a million hectares of land around Gambella to grow basmati rice. The government in principle will not object if Chinese grow sesame in Ethiopia, although areas suitable to sesame such as Humera and Metema are already quite full, held by local people, who rent the land. Thus the regional government allocated (announced) no land for investment. But if someone comes and applies for land in areas such as Gambella and Pawe, where the land is free of small holders, and where population pressure is low, they are ready to give permission. Nevertheless, this exposes the land to deforestation and soil erosion unless it is cultivated wisely. The Ethiopian Reporter recently reported (Demissie 2009) that China has been unable to produce enough sesame seeds to meet its own demand. This has led to a strong increase in demand for Ethiopian sesame seed; notably, sesame production in Ethiopia is near organic standards. Now, the Chinese are interested in one of Ethiopia’s very desirable products on the international market, as sesame is the second largest foreign exchange earner for the country. Some worry that the Chinese could dominate the production and the export market to the detriment of peasant producers in Ethiopia. Will Asian imports swamp African manufacturing? Will these large loans lead to a new debt crisis? Does “no strings attached” financing worsen efforts to improve governance? Will Asia’s lower standards for labor and the environment pose a threat to development in Africa? Do Asian contractors tend to use their own compatriots as labor on their projects? Without question, China is the primary destination for Ethiopian sesame exports. Ethiopia’s Prime Minister Meles said in an interview that the agriculture sector is open to Chinese investors, but the first priority of Sino-Ethiopian cooperation is infrastructure, the second is manufacturing, and only then agriculture. Desta (2010) detects that because of the world-wide economic and food crises, a significant number of the Ethiopian people are impoverished, and the government has publicly admitted that it is purchasing grain from the international grain market to feed the malnourished segments of its population. Given this revision of the government policy, Ethiopia has already committed to handing over 1.7 million of the 2.7 million hectares of arable land to foreign investors. Saudi Arabia has invested in flori/horticulture and meat and biofuel production, as well as rice cultivation, mainly in Alwero, Gambella Regional State. India’s investments are in tea, biofuel, sugarcane, and cotton. China is involved in the production sesame and other oilseeds. EU countries, Israel, and the United States are involved in horticulture, vegetable, meat, and biofuel production.

Hazards of Converting from Small- to Large-Scale, Industrial Agriculture Environmentalist Vandana Shiva (2000) charts the impact of commercial agriculture on small farmers, the environment, and the quality and healthfulness of the foods we eat. Shiva observes a conflict between local food production and global capital: the resources of the poor of underdeveloped regions appropriated to generate profits for giant corporations. In the chapter “Soy Imperialism,” Shiva examined how soy oil has replaced traditional seed-oils in a large part of India. Traditionally, oil extraction was as needed, in small quantities, with small oil presses, or ghanis. Oil processing provided employment for thousands of artisans and ensured that the housewife had a fresh product; the oil cake was fed to cattle. Shiva views “free trade” as destroying local markets and robbing the poor of their right to food— even to life. When the food system is industrialized, millions of peasants are forced off their land,

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and a system of agriculture that was once ecologically friendly and diverse is replaced by monoculture cultivation that can be supported only by toxic chemicals. Shiva (2000) argues: “The flooding of domestic markets with artificially cheap imports is stealing local markets and livelihoods from local farmers and local food processors. The expansion of global markets is taking place by extinguishing local economies and cultures.” The U.S. Soybean Association pushed for soybean imports as the “solution.” “U.S. farmers need big new export markets,” reported a business publication. “India is a perfect match.” In Shiva’s view, the growth achieved was by theft of an important part of the small-scale local economy. Shiva points out (2000) that this source of “cheap” vegetable oil has come at great cost. “From seed to distribution to processing, soybeans are associated with concentration of power. While the oil content of coconut is 75%, groundnut 55%, sesame 50%, castor 56% and niger 40%, the oil of soybeans is only 18% … Soy oil is extracted in large solvent-extraction plants. Chlorinated solvents such chloroethylene are used to extract the oil.” Shiva noted that “soya bean and palm oil have flooded the Indian market, destroying the domestic edible oil economy based on coconut, the mustard, the groundnut and the sesame.” Society might reconsider soy’s cost and quality against its cultural/ environmental toll, compared with pure, unrefined sesame oil. Studies such as these demonstrate that current trade-liberalization rules and policies have led to increased poverty and inequality and have eroded democratic principles, with a disproportionately large negative effect on the poorest countries (World Trade Organization Trade Liberalization Statistics 2008). Diversity and sustainable food production systems are destroyed on behalf of increasing food production. But this makes rich sources of local sustenance disappear. Trade liberalization correlates negatively with income growth among the poorest 40% of the population but positively with income growth among higher income groups. Quoting Lundberg and Squire in Inequality and Growth; Lessons for Policy, World Bank (1999), it “helps the rich get richer and the poor get poorer.”

Part III—Sesame Consumption, Merchandise, and Marketing Sesame seeds appear in a spectrum of colors from white to black; however, two broad groups are in commercial trade: white and black. Customarily, El Salvador, Guatemala, Mexico, and Nicaragua grow white sesame, while most of the black (dark) sesame on the world market comes from China and Thailand. Bedigian (2000) observed that there appear to be cultural preferences as regards seed color: Chinese, Japanese, and Thai, for example, prefer their local black-seeded sesame, whereas many in Europe, Southwest Asia, and the United States prefer local white-seeded cultivars for confectionery. This may depend on use: for example, for making halvah, lighter colored seeds are preferred. White seeds receive a higher market price than mixed seeds, which range from yellow to dark brown; white seeds are often used raw, because of their aesthetic value, whereas, more generally, dark seeds are crushed into oil. The value of sesame seeds depends on their purity, expressed as percentage, and oil content, which preferably should exceed 50%. Hulling the seeds, or removing their thin testa/seed coat, increases their value, as does bleaching hulled seeds. Moisture content and free fatty acid content are also important in assessing value. According to Utterback (n.d.), the highest-quality sesame seeds come from Central America, primarily Guatemala.

Food Consumption Trends in the United States Increase Economic Importance of Sesame Hulled or decorticated, roasted or raw, sesame’s use in baking is primarily as a topping on bread, hamburger buns, bagels, and bread sticks, in candy making, and with other foods. The bakery industry prefers hulled seeds, which make up 50% of the U.S. consumption. The American Institute of Food Distribution (2001) reported that Americans consume more than 70 million pounds of sesame seeds a year, largely on hamburger buns, according to Food Technology magazine’s “2001: A Spice Odyssey.” The American Spice Trade Association (2002), reporting for the supermarket grocery

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business, rated the top 12 spices in U.S. consumption for 2000, by market size, in weight. Sesame ranked fourth, at 108,133 pounds, following dehydrated onion/garlic, mustard seed, and red pepper (except paprika). Next in sequence were black pepper, paprika, cinnamon, cumin seed, white pepper, oregano, poppy seed, and ginger, in descending order. Any event can trigger a spike in interest in a particular food. When the 1954 Grand Prize winner of Pillsbury’s Bake-Off® contest selected Dorothy Koteen’s Open Sesame Pie, supermarkets nationwide sold out of sesame seeds (Pillsbury Bake-Off® Contest Winners Recipe Collection, Grand Prize and Hall of Fame Recipes 1954). Sesame foods are increasing in popularity. Products sold in U.S. grocery and health food stores with sesame seed as an ingredient include sesame crackers, whole grain and sesame cereals, sesame chips, and sesame seed candy, breads, breadsticks, and cookies baked by ethnic bakeries. Worldwide, MacDonald’s accounts for some significant amount of seeds consumed, since sesame seeds decorate every bun. Sesame oil contains natural antioxidants; blended with other vegetable oils, it is an “adulterant” in manufacturing margarine, and it improves shelf life. Extraction of oil from sesame seeds is by mechanical pressing. Bedigian (2004a; Bedigian and Harlan 1983; Chapter 1, this volume) describes some historical presses. Cold-pressed seeds give an aromatic salad oil; oil yield is from 45% to 60%, depending on cultivar. Ethnic foods are increasing in appeal through marketing, and as world travel increases, returning vacationers shop locally with an interest to adopt foods they tried in distant places. Ethnic and specialty food manufacturing is one of the most vibrant parts of the New York City’s manufacturing economy. Interest in ethnic and gourmet foods is also boosting sales of such sesame products as tahini paste, halvah, and sesame seed oil. Tahini, a traditional Middle Eastern sesame paste and the peanut butter equivalent of sesame, consists solely of pure hulled, crushed sesame seed (Bedigian 2000, 2004a). The paste is rich in protein and a very good energy source. Ziyad Brothers, of Cicero, Illinois, a division of Syrian Bakery & Grocery Co., imports tahini from Lebanon. This writer has visited shops selling exclusively tahini and halvah in Aleppo, Syria, and in Istanbul and Trabzon, Turkey. These foods have become conventional in the United States. The crowning producer of tahini in the United States is the century-old ethnic specialty food manufacturing firm Joyva Corporation, of Brooklyn, New York, which supplies tahini to major multinational dip and spread manufacturers that use it in conjunction with chickpeas to produce hummus, and with eggplant to produce baba ganouj. Data provided by manufacturer Richard Radutzky of Joyva Corporation are illustrative (pers. comm. 2009). Joyva currently imports 1400 T of white sesame seed, required for their processes, per year, primarily from India and Paraguay. Since 2007, prices have doubled each year. He notes, too, that while crop production has declined, there is a huge increase in consumption by China and Japan. China is by far the largest user, buying most of the world supply. He foresees a shortage of raw seed in the United States; most of his supply comes from India, but his suppliers there have raised the price. Joyva requires white seed. Chinese prefer black seed, for health uses. Joyva has never made oil, finding an insufficient market here; they manufacture more halvah in winter. A member of the National Confectioners Association, Radutzky is concerned with topics related to marketing, manufacturing, legislation as regards hygiene, and related economic issues, such as farmers subsidies; as U.S. manufacturers, they are required to purchase domestic sugar, which is much more expensive than non-domestic, to support American farmers; the same rule applies to peanuts. Turkish halvah manufacturers also note that sesame prices are going up. Radutzky’s most expensive pieces of equipment are mills and roasters, with the cost of gas for roasting sesame seeds an added expense. He employs 1.5 technicians to maintain the equipment. Photographs (Figures  25.11–17) illustrate the sequence of steps involved in preparing sesame seed for production of tahini and halvah at Joyva’s Brooklyn, N.Y., manufacturing complex. Initially, the seeds, unloaded from 25- or 55-kilogram bags (Figure  25.11), pass through an air separator (Figure 25.12) to remove any foreign particles, such as stones, stems, and insect parts (Figure 25.13).

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Figure 25.11  Joyva warehouse, Brooklyn, New York, unloading 55-kg bags of sesame seeds.

Figure 25.12  Shaker that removes stems, stones, and detritus.

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Figure 25.13  Chaff, stones, contaminants, discarded waste removed by shaker.

Figure 25.14  Salt tanks serve as dehullers.

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Figure 25.15  First rinse tank.

Figure 25.16  Several rinse baths are required.

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Figure 25.17  Hull separators, holding/soaking tanks, and centrifugal driers.

Next, seeds are soaked in salt baths for dehulling (Figure 25.14); the testa (seed coat) surrounding the seed is detached by soaking and agitation in brine to separate the chaff from hulled seed. Salt added to the water by some manufacturers (Bedigian 2004a) increases the specific gravity of the water and accelerates dehulling, but the salty testae present disposal problems, particularly in dry regions such as Syria. Decorticated seeds are rinsed several times (Figures 25.12–17), centrifuged to remove excess moisture (Figure 25.18), and dried thoroughly. Hulled seeds pass through an electronic color-sorting machine to ensure uniformity. This dust-free de-hulled seed has high purity; it is dry roasted at 116ºC (Figures 25.19–20) and crushed (Figures 25.21–23), forming a thick butter. The Japanese, too, enjoy an analogous butter: sweet black sesame paste, spread on English muffins or toast (Tomoko Steen, pers. comm. 2009). Halvah, Joyva’s signature product, is a sesame confection made from sweetened tahini. Figures 25.24–25 show the large copper kettles used for preparation of halvah. Tahini is mixed with boiled and whipped corn syrup, sugar, and several other ingredients in an approximate ratio of 1:1 (Bedigian 2004a). The sugar source for halvah is corn syrup and cane sugar (sucrose). Joyva tested beet sugar, because it was cheaper, but found it foamed and reacted differently, so they rejected it. Sucrose gives a texture of spun sugar threads. Saponaria officinalis L. (Caryophyllaceae), added to impart texture to halvah in the Middle East (Bedigian 2004a), has never been used by Joyva owing to its unavailability here; instead they use albumin (egg whites) to add fluff and froth. Joyva manufactures Halvah bars (Figure  25.26) coated with dark chocolate (Figure  25.27); in its bulk form, almond or pistachio nuts, as well as ribbons of chocolate syrup added to some blends, increase temptation. Halvah is suitable as a vegan food. Joyva also manufactures crunchy sesame brittle. Greeks enjoy halvah with lemon juice and a bit of cinnamon powder as a popular meze (tidbit) with white wine. An unsophisticated, naive person is called “a halvah” (aftos einai halvas = “he is like halvah”), that is, he is clueless, according to George Babiniotis’s New Dictionary of the Greek Language, perhaps because of the featureless appearance of halvah (Kosta Tsipis, pers. comm. 2007). An elaborate restaurant dessert that uses halvah (Thorn 2007) is a baked caramel-banana desert, which a chef describes as tasting like “sesame cotton candy” topped with a quenelle of tahini ice cream and a piece of candied vanilla bean.

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Figure 25.18  Centrifugal dryer, detail.

Figure 25.19  Sesame seed roasters.

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Figure 25.20  Roasters, detail.

Figure 25.21  Toasted seed fed into crusher.

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Figure 25.22  Fresh tahini.

Figure 25.23  Joyva owner Richard Radutzky with 40-lb. containers filled with tahini.

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Figure 25.24  Copper kettles ready for mixing halvah.

Figure 25.25  Tahini residue in copper kettle, after mixing.

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Figure 25.26  Blocks of halvah.

Figure 25.27  Chocolate-covered halvah bar.

Raphael Grougnet (Chapter 4, this volume) provides a delightful description (pers. comm. 2007) of his experience of the Greek Orthodox first day of Lent celebration called Kathara Deftera, or “Clean Monday”: “They don’t eat meat, only octopus, squid, or mussel. The traditional sweet for this day is halvah! Imagine a day when everybody in the country will eat halvah, pure, or with chocolate, almonds, vanilla … As I told you, I prefer tahini, because it’s not so sweet, but OK, halvah covered with chocolate is fine also. Last year, we visited, with my professor from the lab, a huge sesame factory close to Thessaloniki, Haitoglou Bros. It is very famous in the country. They showed us all the process from the sesame-bag coming from Ethiopia or Sudan, until the tahini, or halvah, or oil. They also produce pure seeds for bakery, by dehulling.”

Natural Foods Trends: Healthy Diets Trends toward healthy eating are becoming standard, as diet- and lifestyle-related health problems have been well publicized in the media in recent years. Awareness of trans-fats is driving technology and edible oil market trends (Kee 2009). The New York Times series Recipes for Health features tahini recipes for the week October 19–26, built “around a particular type of produce or a pantry item … food that is vibrant and light, full of nutrients but by no means ascetic, fun to cook and a pleasure to eat” (Shulman 2009a, 2009b).

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According to Pitchford (1993): “Sesame seed should be ground up before eating or cooking to make them more digestible. They become even more digestible with soaking overnight, then lightly pan-roasted before grinding. This helps to reduce the effects of their substantial oxalic acid content, which ties up calcium and other minerals. ‘Sesame butter’ is whole sesame seeds milled into butter; ‘sesame tahini’ is made of sesame seeds with their hulled removed before milling. Tahini contains less fiber and is thus less laxative than sesame butter. Because oxalic acid is contained in the hull tahini is considered better for those in need of sesame’s rich store of calcium.” The place of sesame in prevention and treatment has led to increased consumption of snack treats containing sesame, such as halvah and sesame brittle. McBride (1998) studied the significance of phytochemicals to human health, which compared a diet high in refined foods and low in fruits and vegetables versus a diet rich in leafy-green vegetables and fruits, whole grains, raisins, nuts, and sesame seeds. When 12 female volunteers switched from the refined-foods diet to the plant-rich diet, they were able to relax their antioxidant defenses. A copper-containing enzyme, superoxide dismutase, that protects delicate cell parts against oxidation decreased by two-thirds. The seleniumcontaining antioxidant enzyme glutathione peroxidase dropped by one-third.

Organics Organically produced sesame is preferred in the global market. Organic sesame seeds for Eden Organic Sesame Oil, a prominent purveyor in the United States, are grown in Michoacan, Mexico (Sue Becker, Manager of Marketing Department, Eden Foods, Clinton, Michigan, pers. comm. 2009). The crushing facility is in located in the city of Cortazar, state of Guanajuato, Mexico. Eden Foods has enjoyed long-term relationships, over 10 years, with their growers and the crushing facility, and no changes are planned. Bio International (2001) introduced its single-serve Bio International Organic Food Bar. The “non-GMO” snack bar contains 15 g protein, 31 g carbohydrates, 12.6 g fats, 1.4 g saturated fat, and less than 5 g sugar. The ingredients include quinoa sprout powder, fava bean sprout powder, soy sprout powder, sesame seeds, date paste, raisins, almond butter, rice protein powder, honey, rice crisps, and sterolins. Hanover, Pennsylvania–based Snyder’s has launched a line of organic products, including Honey Wheat Sticks with Sesame Seeds. Del Campo (2007) is a farmer-owned co-operative that exports agricultural products to the world market; it pioneers new organic products for export, and today remains one of the largest exporters of certified organic products in Nicaragua, including high-quality sesame contained in their tahini. Faced with the reality that small-scale farmers often grow sesame as a cash crop, but experience economic and technical barriers to improve their returns, Del Campo represents 3500 small-scale farmers on Nicaragua’s Pacific Coast, who grow more than 1500 T of sesame seed annually and are the largest exporter of sesame in Nicaragua. These are fairly traded products that guarantee transparent benefits to small farmers.

An Example from Mexico Business Monitor International Ltd. (2006) reports in the article “Furious Activity in the Organics Market, as Domestic Consumption Rises and Foreign Demand Soars” a significant interest in Mexico, both in production and consumption of organic foods, including sesame: “Organic foodstuffs such as fruits, vegetables, aromatics and medicinal herbs, legumes, grains, meat and dairy products are becoming more popular in Mexico by the day. Over the last few months, the country has increased its production of organic foods and has taken first place in organic coffee production around the world. Organic coffee represents around 60% of the total production of organic foods in Mexico. Other organic foods currently produced in Mexico are: avocados, mangos, bananas, pineapple, sesame seeds, vanilla, cocoa, soybean, cucumber, pepper, chickpeas, garlic, blue corn and onions.

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“We estimate that more than 30,000 producers across the country are now dedicated entirely to organic farming, and that, during the past five years, the amount of land in Mexico devoted to organic crops has increased from 25,000 ha to over 110,000 ha. The southern states of Chiapas and Oaxaca have the largest surface areas devoted to the production of organic crops. In addition, the Mexican government is helping organic farmers by rebating up to 75% of the costs of certification required for organic farming. With organic food exports reaching an estimated U.S. $145mn by the middle of 2006, Mexico exports more organic food products than it imports. BMI estimates that close to 85% of the organic food produced in Mexico is exported.”

Innovative Retail Trends, New Merchandise, New Uses As Asian foods appear more regularly in kitchens worldwide, sesame seeds have emerged as a leading contender (Petran 2000). Q.P. Corporation, Japan’s largest maker of salad dressings, says the sesame dressing it introduced last year now outsells all 44 of the company’s other kinds (Siemering 2001). Perhaps it is because the nutty taste of roasted sesame pairs so well with purported health benefits. Japanese researchers say sesame seeds supply essential amino acids, reduce cholesterol, and “boost the functions of the liver,” according to a report in The Nikkei Weekly. Food writers wax lyrical about sesame. An aptly titled piece, “Innovate Chefs Open to Sesame” (Thorn 2007) praises sesame for adding crunch, thickness, and nutty aromas to everything from appetizers to desserts. “Few ingredients enjoy enough popularity to make it in fast food burger restaurants and yet still bring an air of the exotic to dishes in independent restaurants. In fact, sesame seeds may be the only one.” Rice vinegar and sesame oil (2001) join the offerings by one of the largest soy sauce manufacturers in the world. Wan Ja Shan Mandarin Soy Sauce introduces its new line of seasoned vinegar and blended and pure sesame oils to its full line of oriental sauces including Hoisin, StirFry, Tamari, Teriyaki, and soy sauce. Following this flavor trend, Trader Joe’s introduced a sesame salad dressing, and a favorite rapidly expanding restaurant menu item is sesame noodles. Lewis (2008) reports that the specialty oil brand Chalice claims it has launched a market first with Fiery Toasted Sesame Oil, the first spicy sesame oil, to tap into the popularity of Thai food. Perlik (2006) describes a dish prepared by Executive Chef Dean James Max of 3030 Ocean, a modern American restaurant in Fort Lauderdale, Florida. Max “perches crisp Gulf shrimp atop avocado purée and citrus sauce in a seasonal recipe that evokes the essence of Florida summers. Toasted sesame seeds and sesame oil lend a nutty taste and suggestion of Asian flair to tempura-style batter used to coat the shrimp. Each shrimp is immersed in bubbling peanut oil before being dropped in for full cooking to prevent them from clumping together or sticking to the bottom of the fryer.” Amisa Organic Spelt Sesame Sunflower Crispbread 200 g are spelt crackers topped with sesame and sunflower seeds. The ingredients are spelt wholemeal flour (55%), sunflower seeds (15%), sesame seeds (12%), linseed brown, oat flakes, millet, soya meal, margarine (vegetable fat, sunflower oil, water, emulsifier: soya lecithin (No GM), lemon juice, natural aromas), sea salt, yeast, baking aid (lupin flour, barley malt flour, spelt flour, raw cane sugar, spelt malt flour, acerola fruit powder), wheat gluten. The Marketing Intelligence Service reports that Chocolate Tree (2002) introduced Fructose Brittle and Sucrose Brittle to consumers in South Africa, marketed under The Snack Tree name. Each of these brittle health bars is available as Nut and Seed, Raisin and Seed, and Sesame Seed variations. According to trade literature, the fructose brittle bars are suitable for diabetics. Pehanich (2003) praised “rising star” Frontera brand’s line of bite-sized tortilla chip varieties including Roasted Tomato Cilantro, Stone Ground Blue, Garlic Jalapeno, and Chipotle Sesame. A quote by Mexican star chef Rick Bayless on the label of the Chipotle Sesame Chips describes the snack as “Smoky, spicy, nutty—perfect flavors to burst against stone-ground corn.” Habibi-Najafi and Alaei (2006) investigated a nutritious date syrup/sesame paste blend, intended to increase date consumption and produce a value-added product from poor quality dates. Although

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these authors depict it as a novel product, Bedigian (2004) described an ancient aphrodisiac use of a similar mixture in Wadi Hadhramaut, Yemen. Camel’s Milk Chocolate. A joint venture between an Austrian chocolate maker, an Abu Dhabi dairy, and the Abu Dhabi royal family presents a sweeter, smoky-flavored, and less fatty milk chocolate made with camel milk, Yemeni honey, and sesame seeds. Branded Al Nassma, after a cool desert wind, Camel’s milk chocolate (2007) is sold in luxury outlets in the Persian Gulf and aboard the region’s airlines. Featured on National Public Radio (NPR)’s Morning Edition, broadcast July 22, 2009: “A new delicacy is coming our way from Dubai: milk chocolate made with camel milk. The chocolate company has 3000 camels on its farm and currently sells its chocolates in luxury hotels. The company manager says they’re made with local spices, nuts and honey. Each chocolate bar is shaped in the form of a camel.” Wasabi Sesame Seeds. Roland Food Corporation, New York City. Product of Taiwan. Ingredients: sesame seeds, salt, sugar, beta carotene, natural wasabi flavoring, yellow dye no. 5, blue no. 1. Serving size 1 tsp. Chinese Date Bun. Suzhou Buerjia Food Co., Ltd., Cangshushi Dock, Wuzhong District, Suzhou, China. Ingredients: super flour, jujube (Ziziphus jujube Mill. (Rhamnaceae), unspecified nuts, sesame, sugar, vegetable oil and roses, “made from pure raw materials, without addition.” Author’s notes: Thick jujube filling, which the Chinese call “dates,” lend a smoky taste, perhaps resulting from their having been processed over wood fires, which enhances the flavor, just as bananas do in some Vietnamese-village-made sesame candies from Hue. A shortbread-style cake, with roses adding an unexpected elegant flavor, coated with white, untoasted sesame seed. Not sweet, except for the filling. The product preserves well, solidly packed individually in air-tight cellophane, enhanced by elegant packaging: a stylishly illustrated shiny red hexagonal box, with a short red cord handle. Rose petals are featured in another item available during the Lantern Festival (Taylor 2005), which falls on the 15th day of the 1st month of the lunar year, usually in February or March. It is also the day of the full moon. During the festival, there are performances and dances during the day, while in the evening magnificent lanterns of various shapes and sizes hang in the streets. During the Lantern Festival people eat yuanxiao, which are small dumplings made from glutinous rice flour with either sweet or salty fillings. Sweet fillings are made of sugar, walnuts, sesame, rose petals, sweetened tangerine peel, bean paste, or jujube paste. A single ingredient or any combination may be used as the filling; a salty variety is filled with minced meat or vegetables, or a mixture of both. Yuanxiao are also known as tangyuan, which in Chinese has a similar pronunciation to tuanyuan, meaning “reunion.” People eat them to denote union, harmony, and happiness for the family.

Flushing, New York, Market Study Flushing, a neighborhood of Queens, has New York’s highest concentration of Chinese food stores. A survey of the extensive array of articles containing sesame in several supermarkets in the area on January 23, 2009, revealed high spirits and exuberance: one day before the start of the Asian New Year celebration, shoppers thronged the streets and shop aisles. Each product’s ingredient list, label description, and author’s notes appears below: Guifaxiang Fried Dough Twist. Guifaxiang Mahua Food Group, Ltd. 32, Dongting RD, Hexi District, Tiajin, P.R. China. Famous Chinese snack food since the 1920s. Guifaxiang Shibajie Mahua is a traditional food of Tiajin with a long history. The character of Mahua comes from its carefully selected ingredients, outstanding production, beautiful style, and sweet crispness. Ingredients: wheat flour, soybean oil and peanut oil, sugar, sesame seeds, peanut, ginger, orange skin stripe, peeled walnuts seed, Osmanthus. Guarantee 180 days (store in cold, dry place, normal temperature). Author’s notes: a hard cruller, fried crisp, of complex strands of twisted dough that contains sesame seeds, walnuts, slivered ginger, ground peanuts, and shredded orange rind. Individually wrapped, each with its own desiccant pack. Osmanthus flowers grow in small panicles, and in several species they have a strong fragrance. In China, Osmanthus tea (Chinese: 桂花茶; pinyin: guìhuā chá) is

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produced by combining dried sweet Osmanthus (Osmanthus fragrans) flowers (Chinese: 桂花; pinyin: guìhuā) with black or green tea leaves in much the same manner that the more familiar jasmine tea combines jasmine flowers with tea leaves. Zhimagan. Goodtaste. Chongqing Jianglin Shunfa Sesame Candies Factory, 23 Heba St., Degan Jianglin, Chongoing. Ingredients listed in Chinese only. The package states, “With most up-to-date equipments and technique, healthy choice. Our factory was set up in 1989. It professionally produces sesame poles, the so-called sesame candies, which is a local traditional characteristic. The raw materials of this product are all carefully selected. We adopt a traditional craft and combine modern science and technology innovation to produce. The sesame candies are not mucilaginous but sweet, crisp, tasty and refreshing. It is listed as one of famous and special local products of Chongqing now.” Author’s notes: The package illustrates sesame capsule releasing seeds, persistent sepals, stem, and leaf. The surfaces of these rolls, ca 1.2 cm wide, are covered densely with hulled sesame seeds. The texture of the cylindrical-shaped bar is firm and crunchy. This seems to be prepared as rolled spun sugar, caramelized to a crystalline texture onto a rod, subsequently removed, and then hot sugar is rolled into the sesame seeds. The flavor is reminiscent of peanut butter candies coated with sesame seeds. Gingko Sesame Cracker. Aji brand, Taiwan. “It’s delicious and crisp, the mouth overflow with wonderful spice” and “Make it conscientiously” are on package. Ingredients: wheat flour, sugar, palm oil, corn starch, peanut, white sesame, lotus, salt, raising agent, flavoring. Individually wrapped, 2 per pack. Author’s notes: Package shows black sesame seeds, but contents indicate white sesame. Package depicts lotus seeds. Whole sesame seeds are included in an airy, flaky cookie with browned edges. Tastes of peanut. Japanese Mochi. Royal Family Food Co., Nan-Tou City, Taiwan. Ingredients: maltose, sugar, glutinous rice, starch, palm oil, sesame, flavor, sorbic acid preservative. This carton has three mochi fillings: red bean paste, sesame jam, and peanut jam. Author’s notes: Uneven amounts of fillings in moist, soothing glutinous rice balls. Three types: 1) with outside coating of multi-colored sesame seeds; 2) red bean paste filling coated with an unidentified starch; 3) coated with crushed peanuts, filled with peanut paste. Overall, not preferred to the black sesame selection made by this company. Rice Cake. Hao Han Food Factory Co. Ltd, No 17, Lane 530, Jhongjheng N. Rd, Sanchong, Taipei, Taiwan. Ingredients: glutinous rice powder, sugar, glucose, sorbic acid, and sesame filling. Made in three flavors: red bean paste, sesame jam, and peanut jam fillings. Author’s notes: multicolored sesame seeds coat flat dry rice balls filled with meager sesame paste filling; mostly rice. Biscuits Sesame Biskut Bijian. Shoon Fatt Biscuit & Confectionary Factory, Banjar, 36000 Teluk Intan, Perak, Malaysia. Ingredients: wheat flour, corn starch, palm oil, sugar, sesame, milk powder, vanilla, leavening. Author’s notes: plain vanilla cookie, bland. Seasoned Anchovy Fish with Sesame. Thai World Import & Export Co., Ltd 2532 Trok Nokket, Ratchadaphisek Rd., Bangklo, Bangkholaem, Bangkok, Thailand. Ingredients: anchovies 85%, sugar 5%, sesame 5%, palm oil 4%, salt 1%. Author’s notes: crunchy dried anchovies, stirred into a syrup glaze with sugar, salt, oil and white sesame seeds. Sesame Soft Candy, Kęo Mè Xũ’ng Huê. Golden Dragon Fish Brand, Quality Foods of Vietnam. Ingredients: sesame, peanut, sugar, tapioca starch, maltose. Author’s notes: round discs ca. 9–10 cm diameter, with strong sesame flavor. Thin, soft and chewy matrix consisting of crushed peanut, tapioca starch, and maltose has a generous covering of hulled, toasted sesame on upper and lower surfaces. Golden Sesame Chips. Nice Choice, Taiwan. Dessert. Ingredients: wheat flour, sesame 9%, palm oil, brown sugar, glucose, maltose, soy sauce, salt, bran, wheat germ. Author’s notes: crunchy chips coated with sugary glaze. Meiji Almond Goma. Nishin Trading Inc., Brooklyn, New York. Product of Japan. Label says, “A splendid combination of almonds and chocolate.” Individually wrapped chocolate-covered cookies. Ingredients: sugar, almond, cacao mass, wheat flour, whole milk powder, palm oil, lactose, cocoa butter, sesame paste, shortening, trehalose, cream powder, malt extract, soy sauce powder,

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skim milk powder, salt, sorbitol, emulsifier [soya, lecithin], artificial flavor, squid ink color, MSG, Vitamin E. Wafer-thin, cigar-shaped crunchy rolls, reminiscent of egg rolls with sesame filling.

Black Sesame Health Craze Mintel Global New Products Database (2007) heralds Asia as a region known for its groundbreaking health food trends. The rising popularity of probiotics originated in Japan with the introduction back in the 1930s of Yakult, a milk-like product made by fermenting a mixture of skimmed milk with a special strain of bacteria. It is not only the flavor, smell, and appearance of food that is important, but color as well. The color food trend in Asia involves marketing ingredients with the same color and similar properties for more effective health benefits and is proving to be a driving force in new product invention (Zhang et al. 2009). Appetizing “black” foods such as black sesame and black soybean are reputed to contain more anthocyanins, isoflavones, and minerals and have more health benefits such as containing antioxidants. The topic was significant enough to warrant a slot at the China Conference on Sesame & Sesame Products (March 22–24, 2008), Beijing: “General Production Situation & Development Trend of Chinese Black Sesame Seed.” There is sound basis for East Asian claims that black sesame seed confers health benefits. Antioxidant constituents were examined in the seed coats of black seed (Shahidi et al. 2006; Shyu and Hwang 2002; Xu et al. 2005). Researchers have discovered that sesamin has effects of preventing hypertension and cardiovascular hypertrophy, protecting the liver, resisting oxidation, reducing cholesterol, and being an anti-cancer agent. Chapters of this volume by Grougnet et al., KamalEldin, Mak, Chiu and Ko, Shehadi and Tan, and Thompson and Sacco review the newest details. Changsha Organic Herb (2009) now markets sesame oil pressed from natural black sesame seed containing “sesamin, sesame seed lignan,” listing the following benefits: antioxidant sesamin helps protect blood vessels by scavenging free radicals; bactericide; insecticide; decreases fat storage; antihypertensive; liver protection against alcohol damage, improves liver function; decreases cholesterol levels, increases HDL; anti-inflammatory; protects against UV damage. Mintel’s New Products report (2007) advocated: “Black sesame seeds in particular contain high levels of calcium, protein, iron and magnesium to benefit the kidney and the liver, and are a good source of essential fatty acids.” Now mainstream companies such as Kellogg’s are promoting Black Sesame Seed Cereal in Korea, and Blue Ginger® Multi-Grain Brown Rice Chips Black Sesame & Sea Salt in the United States; black sesame figures in Bissinger’s Naturals Chocolate Covered Black Sesame Crunch. Aji Ichiban black sesame fish fillet (2006) consists of savory black sesame filling sandwiched between two thin layers of dry cod jerky cut into thin strips. It is dry and chewy like any good jerky, but neither tough nor stringy. Each bite into the sesame seed filling releases a bit of toasted sesame flavor—very hard to find outside of Hong Kong or large Chinatowns. Bánh Chung is Vietnamese fare of sticky rice wrapped in banana leaves and stuffed with mung beans, pork, and black sesame seeds, traditionally eaten during the Lunar New Year (Tet) (Vietnam n.d.). “Sesame’s a hot topic today at Sumile Sushi,” says Josh DeChellis, the New York restaurant’s chef. DeChellis is a particular fan of black sesame, which he buys in a paste for his signature “sesame dice” dish. He says black sesame tastes and smells different from white sesame. Toasted white sesame has more aroma than toasted black sesame, DeChellis says, but it’s a more generic toasty aroma than that of black sesame, which he says has more of the smell of pure sesame. For the sesame dice, he adds simple syrup to the paste and then gelatin. He pours the mixture onto a sheet, lets it gel, and then cuts it into cubes. He dresses the cubes with muddled cherries, a little shiso, and a white-sesame nougatine dusted with powdered sugar. DeChellis says good black sesame reminds him of bitter chocolate, although it can also be reminiscent of peanut butter. Thorn (2007) reveals that Jordan Kahn, pastry chef of Varietal, also in New York, agrees with DeChellis that black and white sesame taste different. He ascribes an earthier quality to the black seeds, and says it is more subtle: “It’s not nearly as punch-you-in-the-face as white sesame.” He says

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the quality of black sesame varies greatly, and he has had most success with suppliers of Japanese seeds. Kahn also has made black sesame oil by toasting the seeds until they give off an aroma, blending them with a neutral tasting oil, letting the mixture sit for a few days and then decanting it. DeChellis says he has given up on making his own black-sesame paste because of the inconsistency of the seeds, which are sometimes stored in the vicinity of other spices and thus take on their aromas. Food writer Betty Hallock wrote rapturously about black sesame in a multi-page spread, “Symphony in Black” (2006): “Mason of [the eatery] wd-50 infuses his ice cream with a superfine black sesame powder imported from Japan.” Quoting him, “It’s fine like dust and it turns the ice cream a mad gray color. I love the battleship gray. It’s gorgeous. It’s super sexy.” Even in Paris, black sesame seeds are making a showing. At Patisserie Sadaharu Aoki, the black sesame macaroons and black sesame éclairs are among the popular pastries. Japan is in the throes of a “sesame boom,” according to industry insiders. Japan is the largest single importer of sesame seeds in the world. There, traditional uses include goma dofu, a sesame tofu, and wagashi. A new focus on the health benefits—some proven, some not—of sesame seeds and “black foods” (black soybeans, black rice, Chinese black tea) has helped popularize black sesame. The newest addition to the dessert menu at Beacon in Culver City includes a black sesame crème brûlée. Pastry chef Daniel Espindola says a Chinese sweet black sesame soup, called zhi ma wu, inspired him. The crème brûlée is thick, creamy, and dark. A black sesame cream puff is a bestseller at Keiko Nojima’s 10-month-old Patisserie Chantilly in Lomita, in the South Bay of Los Angeles. Nojima did not offer that flavor every day until customers demanded it. She was inspired by pastries in Tokyo, where she served an apprenticeship and where patisserie flavored with black sesame is common. Nojima also makes black sesame tuiles and a white sesame blancmange with black sesame seeds and kinako sauce, made with soy flour. Helm (2007) related: “On Asian plates, black means healthful. Dark varieties of rice, beans, seeds deliver nutrition. Black dominates the decorations and costumes of Halloween, but you may want to add black to your plate, too. Black-colored foods are a signal of health in some parts of the world, and it may be the next big nutrition trend in this country. The black food craze is red-hot in Asia, particularly Japan, and it may be poised to jump West, according to Simone Baroke, health and wellness analyst for Euromonitor International.” The Nation’s Restaurant News (September 11, 2006) featured Dish of the Week was Chocolate Shanghai Soup Dumplings at the Rickshaw Dumpling Bar, New York: “Chef Anita Lo prepares a ganache of chocolate and butter. She wraps that in a sweetened rice dough called mochi and rolls that in black sesame seeds. The dumplings are deep-fried and served hot, so the ganache is liquid.” Oliver (2008) focuses, in “Nutrients Noir,” on the beneficial effects of dark-colored foods to the human body. Traditional Chinese Medicine teaches that dark foods tonify the energy channel and nourish the blood. Black soybeans contain high levels of polyphenols, which can prevent the oxidation of LDL cholesterol; black rice contains anthocyanins that can prevent insulin resistance, while jet-black sesame seeds are rich in antioxidants. Aoki (2009) excerpted praises for Black Potage (soup), translated from reports by Nikkei M.J., November 24, 2008: “Time and time again, the color black is an attention getter for food products in Japan. Asahi Beverage has come out with a new product called ‘Black Potage.’ The black color is a result of black sesame paste added to corn soup. Black sesame is an ingredient that has received much positive attention from nutritionists for its health benefits.” Similarly, Okashi (Japanese Snacks) (2009) raves about Glico Pocky Kurogoma (Black Sesame): “Kurogoma is a mixture of black sesame, black rice, black soy beans, black pine nut and black quince in what tastes like white chocolate. Sounds weird? It’s actually a very tasty combination. If you like those little sesame sticks in snack mixes, you’ll think these are yummy!” A blogger’s response: “Trust the Japanese to make junk food classy. These black sesame sticks are addictive. They don’t have the snap and crackle of Glico Pretz but are richer and more flavorful. No wonder, for they are essentially white chocolate sticks studded liberally with black sesame seeds, rice and wheat puffs and hazelnut paste.”

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The Japanese make a candy that has a hard surface and is filled with threads of spun sugar mixed with black sesame paste; it shears in sheets and slivers of grainy flakes the consistency of halvah. Crunchy, it resembles the Butterfinger® candy. Another Japanese specialty item is sweet black sesame paste, akin to peanut butter, a spread on bread and English muffins. Marriot (2009) urged, in “Changing Trends in South Korean Food Market”: “Packaged foods that are basically healthy could endure the current economic pressure … Ingredients like green tea, black bean and black sesame are specifically popular.”

Black Sesame in Products Available in New York City’s Chinatowns, 2008 and 2009 Good-Vita Natural Oat Cracker, Dong Guan Kam Tai Co. Ltd., Xi Ping Village, Nancheng area, Dong Guan City, Guang Dong, China. Naturally good for you. Silang Black Sesame. Ingredients: wheat flour, white sugar, edible palm oil, wheat bran, starch, egg, oats, black sesame, raising agent, salt. Individually wrapped, 2 per pack. Author’s notes: Excellent mealy texture imparted by oats and wheat bran; sesame flavor pronounced, perhaps seeds were toasted; crisp oat flakiness, not very high sugar content. Whole black seeds are incorporated into the dough. Brown Sugar Mochi [= chewy rice cake] Sesame flavor. Royal Family Food Co., Nan-Tou City, Taiwan. Ingredients: maltose, sugar, trehalose, starch, brown sugar, sesame jam, soy bean powder, flavor, sorbic acid preservative. Author’s notes: Chewy glutinous rice cake, good flavor and generous black filling. Package shows black sesame and black filling; unspecified starch; the Internet says potato starch is used for these mochi. Sesame Candy “Powder Type Cold Cooked Cakes.” Shortbread, sweet. Suzhou Buerjia Food Co., Ltd, Canshushi Dock, Mudu, Wuzhong, Suzhou, Jiangsu, China. Ingredients: flour, sugar, sesame, vegetable oil, glucose, maltose. Shelf life, 180 days. Storage method: dry shade, Kaifeng immediately after eating (refrigerate after opening), temperature < 15ºC, relative humid < 70%. Author’s notes: Powdered sesame coats these rectangles of unique consistency. Log form, center is white, outer dough is grayish white; separates into layers of soft flaking dough. Sesame Brown Rice Wafer, Ming Chi Food Co., Ltd. No. 198-3,4,5, Fute Lane, Natseng Village, Tienwei Hsiang, Changhua County, Taiwan. Vegetarian. No preservatives, no artificial colors. Ingredients: wheat flour, corn starch, milk powder, cocoa powder, sugar, glucose, vegetable oil (corn oil), sesame paste, flavoring (sesame), brown rice, raising agent. Author’s notes: elegant package shows old round stone manual sesame grinder with larger round stone container below that has a carved channel for releasing the extracted oil. Black sesame illustration on package. These crunchy wafers have a rich dark-brown color, presumably due to black sesame, and the creamy light brown filling tastes of cocoa and sesame, in two layers; not very sweet, but possible with artificial flavor. I-Mei Thin Crispy biscuits—chocolate & black sesame. I-Mei Foods Co., Lot, 10th fl. No. 88, Sect. 2, Hsinyi Road, Taipei, Taiwan. Ingredients: wheat flour, sugar, vegetable oil (palm, coconut), cocoa powder, milk powder, coconut powder, black sesame, salt, leavening agent, artificial choc flavor. Author’s notes: few outright sesame seeds, pronounced artificial chocolate flavor, crisp texture. Dried Seasoned Fish with Black Sesame. Kurogom Iwahi Senbei. Product of Japan, imported by W&H Group, 285 Vandervoort Ave., Brooklyn, New York. Ingredients: sardine, sesame seed, sugar, malt sugar, cornstarch, honey, soy sauce, fish sauce. Author’s notes: Crunchy snack, slightly more pronounced “fishiness” glaze flavored by fish and soy sauces. Bones plentiful, added dietary calcium, and crunchy. Daifuku Red Bean Cake, Mochi Kuro Goma [rice cake]. JFC International, San Francisco. Product of Japan. Ingredients: red bean, sesame seed, rice, glutinous rice flour, rice starch, water, sugar, amylase. Author’s notes: Soft round ball with soft center (possibly starch and amylase), red bean paste, coated with black sesame seeds; 7.5 cm in diameter. Sesame Pan Cake. Hurng Fur Foods Factory, Ltd. Taipei, Taiwan. No artificial pigment and no preservative. Ingredients: wheat flour 69.5%, black sesame (12%) palm olein 10.5%, sugar 7.5%, salt 0.5%. Author’s notes: Squares of flaky crackers, not very sweet.

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Black Sesame Cookies. Gold Sweet Garden, China. Ingredients: wheat flour, partially hydrogenated vegetable shortening (palm and or soybean oil), black sesame, sugar, baking powder, salt. Author’s notes: Bite-size rectangles packed in round plastic container; crisp texture. Sesame Rolls. Shih Fang Hsih, Taiwan. Ingredients: flour, sugar, sesame powder, vegetable oil, corn powder, salt. Author’s notes: Wafer rolls with, black sesame interior. Cracker: Kikusendo goma douraku. Nishin Trading Inc., Brooklyn, New York. Ingredients: wheat flour, sugar, black sesame seed, egg, margarine, white sesame seed, baking powder. Author’s notes: Long, cigar-shaped wafers.

Black Sesame Ice Cream Black sesame ice cream is an early Asian trend that has caught on elsewhere, scoop by scoop. For instance, Haagen-Dazs introduced a new black sesame-flavored ice cream in Japan, a seasonal item made with black sesame paste. Brinnehl (2006) wrote: “This introduction follows the ‘black foods’ trend found strictly in Asia Pacific. Consumers say black sesame has more intense flavor.” At luxury ice cream parlors in New York City, such as Il Laboratorio del Gelato, two types of sesame ice cream are available: toasted white, and black. For the white, they use hulled organic sesame seeds and simply process them in a blender with their cream base. For the black, they use a pure black Japanese “sesame seed only” paste, Hoshi Jun Nerigoma Kuro Kuki Br., and then add Japanese black sesame seeds to that, and then their base. Manhattan’s Chinatown Ice Cream Factory uses both black sesame powder and black sesame seeds, untoasted. Sundaes and Cones uses toasted black seeds: its Chinese owner said they’ve “always made it that way,” referring to it as “healthy.”

Nutraceuticals, Functional Foods, and Extractable Components Sesame oil is a cell-growth regulator that slows down cell growth and replication. It also has antioxidant properties. The oil can neutralize free oxygen radicals. Chapters 3, 4, 5, 6, and 7, this volume, provide dependable details. When the seeds from food-grade, high-oil sesame are processed, the resulting sesame meal contains from 50% to 55% protein. Sesame meal may be blended with other flours for baking and other food uses; sesame meal remaining after the oil is pressed is an excellent high-protein feed for poultry and livestock feed (Bedigian 2000, 2004a). Hossain and Paul (2007) established that sesame meal increased prawn production for monoculture of giant freshwater prawn (Macrobrachium rosenbergii de Man) in Bangladesh. A diet containing 20% fish meal, 10% meat and bone meal, 15% mustard oilcake, 15% sesame meal, 35% rice bran, 4% molasses and 1% vitamin-mineral premixes is recommended to farmers. Sesame meal and flour are emerging markets with significant growth potential; both added to recipes give a better nutritional balance to health food products. The antioxidants naturally found in sesame increase the shelf life of other food products produced with the flour. Arai et al.’s review (2002) of food trends in functional food science and industry in Japan classifies sesamin as a pro-antioxidant. Bröring and Cloutier (2008) evaluated new products and value creation for nutraceuticals and functional foods. They offer some definitions for the growing field of health ingredients emerging “at the boundary of the pharmaceutical and food industries”: A food may be regarded as functional if it satisfactorily demonstrates benefit to one or more target functions in the body, beyond adequate nutritional effects, in a way that either improves health or reduces disease, such lowering cholesterol, or being an antioxidant. Ishigaki (1999) invented a food that is a fermentation product of sesame with antioxidative properties. The technique for fermenting sesame was to digest crushed raw intact sesame seeds with an enzyme derived from Rhizopus oligosporus, followed by lactic acid fermentation. Comline Business Data (1999) reported an experiment by a research team affiliated with Suntory, one of Japan’s top alcoholic beverage producers, joined by the Agriculture Department of Kyushu University, that has uncovered the mechanism behind the liver-protecting function of the compound

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sesamin, a constituent of sesame seeds considered beneficial to the liver. Sesamin provides beneficial effects such as enhancing the liver-protecting functions of vitamin E and DHA, and reducing the amount of cholesterol absorbed in the small intestine. The sesamin constituent of sesame oil is at a level of about 1%. Sesamin is one type of lignan. The protective mechanism in the lignan works by changing into the metabolite catechol in liver cells; this substance then protects the cells from the toxic effects of active oxygen. The anti-oxidation function should prove useful toward the reduction of aging and the prevention of diseases associated with the aging process. Nutritionists are realizing that sesame oil is healthier than most other oils. Phillips et al. (2005) showed that pistachios and sesame seeds contain more cholesterol-reducing compounds than most other nuts and seeds. Among the 27 products evaluated, sesame seeds and wheat germ contained the highest concentration of phytosterols, > 400 mg/100 g.

Pharmaceutical Applications Sesame seed oil is naturally antibacterial and antiviral and is a natural anti-inflammatory agent (Forse and Chavali patent 1998; Kobayashi et al. 2001) in topical preparations and in the traditional medicines of India, Africa, and Asia (Bedigian 2000, 2004a). Sesame oil is used pharmaceutically as a carrier oil. Many “natural” cosmetics now include sesame oil for its antioxidant properties. The oil treats diaper rash; sesame oil swabbed into the nose protects against air-born viruses and bacteria; sesame seed oil cures chronic sinusitis. Cowley and Elliott (1990) described a treatment for burns and scalds. The Chinese herbal salve, Moist Burn Ointment, according to Dr. Xu Rongxiang, will use the nutrition of the body to repair burned skin. A treatment developed in 1979 uses sesame seeds and honey. While success stories do not count as scientific validation, this approach may be worth a closer look.

Cosmetic Industry: Emollient Body Lotion and Soap Sesame oil is valued in the cosmetic and personal care industry globally. Its prime competitors in the cosmetics niche include other vegetable oils such as apricot and peach kernel, sweet almond, and wheat germ, although oil traders have varying impressions of sesame oil’s competitive involvement. All of these oils are in tight supply, says a broker who handles oils for use in cosmetics and personal care products (Santos 1995). Substitution among the oils in cosmetic formulations does contribute to the dynamics of the market. While established consumer products will typically retain their current ingredient list, a broker says that under these tight supply conditions, emerging products are opting for readily obtainable constituents. “[Producers of] new formulations are looking for alternatives to sesame oil because the oil is not as available as it once was,” she says. “Sesame oil was an inexpensive ingredient; now, at this higher price, other oils are being used.” Sweet almond oil inventories are dropping despite higher almond yields in California. Brokers cite a recent USDA grading guideline for edible almonds that reduces the amount of almonds slated for oil production (Chemical Marketing Reporter, 1/30/95). Inspectors grading the crop determine the percentage of damage. Since the standards for retail almonds were reduced somewhat, more almonds are considered edible. This means less material will be available for non-edible applications such as oil. “We’re receiving one-third of what we used to get,” one broker says. “Everyone’s on allocation. Sweet almond oil has been scarce for about two years.” Still, oils such as sesame and sweet almond competing for cosmetics outlets can be ferreted out (Santos 1995). The Marketing Intelligence Service Ltd. (2003) announced a selection of Harnn Natural Home Spa Grain Soap varieties produced in Thailand, offered in the United States by Wattana, Bangkok–based Harnn Products Co., Ltd.: 70-gram boat-shaped bars packed in a paper sleeve label, with white sesame seed and black sesame seed scents available. Promotional literature for the product line boasts: “Harnn Natural Home Spa is a pure and simple concept of guilt free self indulgence with a full range of easy to use natural bath and spa products; each formulation is based on traditional herbal medicine. Rice bran

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oil plays a major role in the products with its natural antioxidants in the form of three natural vitamin-E, tocopherol, toctrienol and oryzanol responsible for softening, moisturizing and sun protection. The entire range of products utilizes ingredients from natural herbal medicine, pure plant essential oils, natural color pigment, preservative free, not tested on animals and no child labor is used in any step of production.”

Skin Care Formulations Neutrogena Body Oil (1999) sesame seed formulation is an ultra-light, non-greasy, easily absorbed natural oil formulated from sesame seeds to help seal in moisture after bathing or showering, leaving the skin feeling soft and silky. British author Michèle Roberts (2005) entertainingly publicized a search trying out products that avoid synthetics in favor of natural substances by caressing her hands with a cream composed of tamarind extract, avocado oil, mango butter, sesame seed oil and mulberry extract. Prance (2009) reported: “The advanced skin care market is at a key point in its lucrative expansion. Increasing consumer demand for effective products that deliver visible results coincides with advances in biotechnology, biology, nanotechnology and peptide technology that can deliver such results for the first time in the history of this industry … multiple sesame and marine-based sebumregulating agents.” Heralded in the Cosmeeting Beyond Beauty Paris 2009 awards: “A triumph for natural ... A new line of skin care products has arrived on the European and U.S. markets that are said to abolish the need for cosmetic procedures to reverse the signs of ageing. Skin care company Euoko, based in Canada, has developed the 24 product based skin care line to focus on five different treatment needs, including anti-ageing and skin whitening. Created using a mixture of marine compounds, fruit extracts and biotechnologically obtained molecules the product range is tapping into a booming desire from consumers to halt and prevent the onslaught of ageing with a more affordable alternative that can be used at home.” Following three years of research into product creation, the company claims that the range adheres to all current trends that are presiding in the cosmetics industry at present. A forerunner, Youthing Strategies (2001) Face & Body Lovely Skin Formula and Birthing Oil is said to be made with certified organic sesame seed oil, as well as geranium, lavender, lemon balm, and neroli essential oils, and d-alpha-tocopherol from soy (vitamin E). Birthing Oil, pure, organic, Ayurveda formula oil is to be used on the abdomen and perineum, especially during the last four weeks of pregnancy; it is claimed to absorb and penetrate, lubricating, softening, and relaxing the underlying muscle and ligamentous structure, thus preparing for the stretching required during labor and birth; it is also recommended for an equal or longer time after the birth event, as it “helps body tissues return to shape without stretch marks.” Expanchimie (1993), established to “specialize in molecular distillation of active principles,” isolated a new active cosmetic principle with the introduction of its sesame oil extract, obtained through the molecular distillation of virgin sesame oil such that the most volatile elements do not deteriorate. Properties include the two natural antioxidants sesamin and sesamolin, a high content of unsaponifiable fraction, and a high percentage of linoleic acid, one of the essential fatty acids. This composition makes it suitable for a variety of cosmetic applications, incorporated for its antioxidant and anti-freeradical properties, as well as for its moisturizing and regenerative qualities. Product applications include sun preparations, anti-wrinkle creams, and cosmetics with moisturizing properties. Baison (2001) has recently introduced to Japan a bath product, Baison India Esthe Bath Additive, based on sesame oil and a variety of Asian herbs. “According to trade sources, sesame oil works to stimulate circulation of the blood and boost lymph functions, thus expelling excess water and impurities from the body and speeding the process of burning fat.” Sousselier (2005) describes Sesamactive thoroughly: “Among the best massage oils, sesame seed oil is known for its rapid absorption into the skin, its perfect balance between oleic and linoleic acids makes a great moisturizing agent and skin protector. A number of new derivatives which aim to extend the use of this oil have recently been developed.” Sesamactive sesame seed oil is “rich in

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unsaponifiables that were isolated and combined for improved efficiency with a special fraction of olive oil unsaponifiables; this mix is dissolved in sesame seed oil to obtain the desirable consistency and skin feel. It exhibits a very high content in unsaponifiables, more than 35%. Unsaponifiables are included in cosmetics, for their benefits: e.g., phytosterols, present in many vegetable oils have a similar structure to cholesterol and play the same role by interacting with lamellar lipid layers and increasing their stability. Their topical application increases moisture (Zettersten). Among them stigmasterol has been proved to exhibit strong anti-inflammatory activity by topical application (Garcia). It reduces TPA induced edema and showed anti-metal-loperoxidase activity. “Sesamactive offers a unique unsaponifiable profile which imparts synergistic properties: soothing activity, emolliency and emulsifying. An ex-vivo test for demonstrating the anti-inflammatory activity was conducted. An independent laboratory performed the following protocol: Skin explants from plastic surgery were placed on a plate, with 24 wells. Inflammation was triggered by 1µg/mL PMA (phorbol myristate acetate), following a 24-hour pre-treatment with Sesamactive. “Sesamactive inhibits significantly (in a dose dependent manner) the release of IL-1_. Inhibiting IL-1_ allows the inflammatory reaction in the skin to be limited and prevents photo-ageing. Inflammation and both UV-A and UV-B irradiation induce the expression of pro-inflammatory cytokine, particularly IL-1_, and activate the PLA2 catalyzed release of arachidonic acid (Bastian) which starts the inflammatory cascade leading to leukotriene release (Sjursen). IL-1_ also induces collagen degradation, as MMP-1 is induced through IL-6 production (Wlaschek) and trans-activation of EGF receptor (Wan). Ultimately, this leads to photo-ageing. Sesamactive soothes irritated skin, prevents UV-induced damage and photo-ageing, provides an unctuous skin feel and stabilizes emulsions (as sterols are co-emulsifiers). Sesamactive is a soft ivory solid, containing 2–5% sesame, used for skin care, soothing products, anti-wrinkle, body butter, lipstick, sun protection, after sun. “Two other derivatives from sesame seed oil are also available: Sesamollient and Sesambutter. Sesamollient: Obtained from sesame fatty acids (INCI: Hydrogenated ethyl hexyl sesamate), Sesamollient is highly stable and presents perfect compatibility with the skin. It spreads easily, penetrates rapidly while imparting a pleasant dry feel to the skin. Sesamollient relieves skin roughness and dryness and restores its suppleness and flexibility. Uses of Sesamollient, Colourless liquid, 2–15%: skin care, make-up, after sun.” Promoters claim that Sesambutter is a natural emollient, consisting of partially hydrogenated sesame seed oil (INCI: Hydrogenated sesame seed oil). It enhances the elegance of its emulsion formulations. Non-tacky, it contributes to a great skin feel by bringing softness. Body butter also benefits from its stability and unctuousness. It eases the spread of finished products, builds up body and structure in a formulation, and repairs dry and damaged hair. Sesame seed oil is not only useful for cosmetic application and massages, but it is now also the source of new ingredients with special benefits for the skin and hair. Naturactiva specializes in marketing “green and blue” cosmetic ingredients creating value and bringing new technology, image, and activity. Soliance recently acquired the company. Applications of Sesambutter, Soft ivory solid, 1–5%: skin care, body butter, lipstick, make-up, after sun, hair conditioner.

Hunting Bait A minor economic contribution, landowners and government agencies grow sesame for wildlife food plots, and as bait to attract game birds. Farmers plant sesame on ditch banks and along wooded creeks to sustain quail and pheasants. In South Carolina, farmers plant sesame as bait to attract dove and quail for hunters (Wannamaker pers. comm. 2009).

Industrial Use A small amount of sesame has industrial applications, but its high price limits growth in that sector. Common uses are in paints, soaps, cosmetics, perfumes, bath oils, and insecticides, and in

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pharmaceuticals as a vehicle for drug delivery. In the past, it was used to prepare India ink, and as a lamp oil. Carlin (2002), citing Soldering and Assembly Technology (2002), reports that Matsushita Electric Industrial Co. Ltd., best known for its Panasonic brand of consumer electronic and digital communications products, announced the development of an easy, efficient, and safe solder-recycling process. Conventional processes use heat or high pressure to separate reusable solder from waste solder residue. In the new process, specially treated sesame seed waste added to the melted compound solder residue of flow-soldering machines separates the reusable solder from the compound. The recycled pure solder, formed into bars, may be used just as solder made from virgin materials. There are three Japanese and four overseas patents on this new method at present. The biological pesticide use of sesame in synergized pyrethrum formulations (Bedigian et al. 1985; Glynne-Jones 2001) deserves renewed attention, in view of its relative safety to humans and animals.

Biotechnology Sesame breeding programs in China, Japan, Korea, Thailand, and the United States now manipulate the antioxidant level as a primary selection factor in selection of future varieties. An assessment of genomic work in underutilized crops (Dawson et al. 2009) indicates: “In Sesamum indicum, expression profiles in developing seed have been compared with Arabidopsis, in order to identify candidate genes involved in the biosynthesis of sesame lignans, which have antioxidant and health protecting properties. Related work is concerned with the possibility of creating more diverse fatty acid compositions in sesame oil, in order to make it more competitive in world markets.” They conclude: “It is clear, however, that biotechnology is not a panacea for promoting underutilized species, and the cost and effort involved in realizing successful interventions will often be much greater than many researchers have first considered, with timescales of decades rather than years being the norm (CGIAR 2006).” Sowmya et al. (2009), from India’s Central Food Technological Research Institute, tested using sesame oil, hydrocolloids, and emulsifiers to replace fat in cakes in the search for low-fat alternatives. Their results show that reduced-fat, nutritionally superior cakes with quality characteristics better than control may be prepared by replacing fat with 50% sesame oil and using a combination of different hydrocolloids. In addition to the fat reduction, the researchers note an improvement in the fat profile of the resulting cakes, with a 2.4 times decrease in palmitic acid, and a 5.9 times increase in the content of essential fatty acids. Emulsifiers, additives that can bind water and oil together in an emulsion, are important in many low-fat foods where the lowered fat content reduces the stability of the formulation. Emulsifiers are often necessary in baked goods and snacks when manufacturers want to remove, reduce, or avoid using trans-fats. Their cake evaluation included batter viscosity, cake volume, and overall quality, with their research leading to significant improvements in the microstructure of cake crumb with a smoother structure. The nutritional profile of the cakes also improved, with the saturated fat content decreasing by over 30%, and unsaturated fats, in the form of linoleic acid, increasing. Saydut et al. (2008) investigated sesame oil for use as an alternative fuel. They extracted oil from sesame grown in Diyarbakir, southeast Anatolia, with conventional solvents. They prepared the methylester of sesame seed oil by transesterification of the crude oil. Their results indicated that “transesterification improved the fuel properties of sesame seed oil,” and the authors support the production of biodiesel from sesame seed oil as a viable alternative to diesel fuel.

Future Prospects The introduction of the nonshattering characteristic into high-yielding, normally shattering cultivars brings some reduction in yield and/or seed quality. Higher-yielding nonshattering cultivars can help

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Figure 25.28  Darfur’s Sudanese refugees at Bredjing Refugee Camp, Eastern Chad, August 9, 2004. Photo courtesy Christoph Bangert, originally published in The New Yorker, January 5, 2009, with “Lives of the Saints,” by J. Harr.

sesame compete with other crops. Cultivars that permit mechanical harvesting, such as developed in the United States and introduced in Thailand (Wongyai, Chapter 21, this volume), hold promise. Only after substantial mechanical harvesting of the crop has been underway for some time will we know what pests may arise to attack the crop under those circumstances. War and famine create debilitation, desecration, and disruption that are permanently altering cultures that have survived independently for centuries, reliant upon sesame farming amidst harsh environmental conditions. It is my ardent hope that the land grabs and industrial agriculture described in Part II neither irrevocably displace nor starve out indigenous populations, nor cause loss of local sesame landraces that have evolved during hundreds of years of human selection. Equipped with a perspective based on nearly four decades of firsthand study of African cultures, and adequate time to reflect on the impacts of wars in southern Sudan, the Nuba Mountains (Bedigian 1988; Bedigian and Harlan 1983), and Darfur, I contemplate the devastation done to subsistence farmers whose agricultural practices I have admired so. The photograph of Darfur’s Sudanese refugees at the Bredjing Refugee Camp in Eastern Chad in 2004, showing vitamin-fortified refined vegetable oil imported from the United States (Figure 25.28), contrasts conspicuously with their former lives as cultivators of the locally abundant, highly nutritious sesame oil crop. The two-page photo spread by Christoph Bangert that introduced Jonathan Harr’s distressing analytical essay “Lives of the Saints” discloses another tragic outcome of the ravaging genocide in Darfur. During a severalmonth (October–December 1999) visit to Darfur in exploration of sesame and its wild relatives, I observed a region rich in diverse crops selected and maintained by stoic, long-suffering indigenous farmers over centuries. The deterioration is marked in Bangert’s photograph that displays recycled cardboard cartons stamped “refined, vitamin A fortified vegetable oil” donated by the United States (probably from the less nutritious soybean). It delicately decries to observant eyes the disturbing destruction of Darfur’s genetic resources of sesame, an excellent source of protein, loaded with the beneficial limiting amino acid methionine and antioxidant-rich oil with innumerable health benefits, including anti-bacterial, anti-viral, and anti-fungal actions. We still lag very far behind the point where sesame should be in world markets, at every level: production, yield, and consumption. One key challenge is to make sure emerging sesame markets have a fair chance of competing in world commodity markets, as new trends globally unfold relating

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to land use, poverty, longer and more punishing droughts, and industrialization of agriculture. There are economic incentives now to expand sesame research and use. Drought-tolerant sesame, regarded carelessly for so long, seems finally to have arrived, offering opportunity for more profit under the current climate of water shortage.

Acknowledgments Catholic Relief Services personnel Tom Remington, Benjamin Safari, Joseph Sedgo, and Robbert van der Steeg patiently indulged my persistent queries about their admirable African projects. Richard Radutzky, Joyva Corporation, Brooklyn, New York, answered many questions about processing sesame during tours of their gleaming facility. Christoph Bangert generously shared his photograph of Darfur’s Sudanese refugees at Bredjing Refugee Camp, Eastern Chad, taken August 9, 2004. The Leonard Lief Library, Lehman College, of the City University of New York (CUNY) and the Science Information and Business Library branch, New York Public Library catalyzed this research. Agricultural economist John Dyck, Economic Research Service, USDA, kindly provided official customs data from various reporting countries, trade matrices for sesame seeds and sesame oil for calendar 2008, and Japan’s imports of sesame seeds and sesame oil for the calendar years 1994–2008, assembled by Global Trade Information Services, Inc. Chemist and computer specialist emeritus D.E. Shaw, U.S. Army Corps of Engineers, guided data analysis thoughtfully.

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National Women Farmers Association (NAWFA). 2009. Oilseeds (Sesame and groundnuts) Processing Project. http://www.nawfa.org/value.html Neutrogena body oil. 1999. International Product Alert 6(18). September 20, 1999. Neutrogena thinks big with sesame seed formulation. 1999. Chemist and Druggist August 21, 1999: 12. New sesame on the street. 2002. New Agriculturalist online. http://www.new-ag.info/02-4/newsbr.html#nb9 Nicaragua Solidarity Campaign. 2002. Nicaragua: Campaign briefing: Fair trade works. http://www.nicaraguasc.org.uk/archive/fair%20trade/fairtradeworks_2002.htm Okashi (Japanese Snacks). 2009. Glico – Pocky Kurogoma (Black Sesame). Squidoo. http://www.squidoo. com/okashi Olam. 2008. Sesame seed. http://www.olamonline.com/globalbusiness/sesame.asp Oliver, H. 2008. Nutrients noir. Delicious Living 24(3): 16. Owens, S. 1993. Catholic Relief Services in The Gambia: Evolution from agricultural research to communitybased experimentation. In K. Wellard and J.G. Copestake, eds., Non-Governmental Organizations and the State in Africa: Rethinking Roles in Sustainable Agricultural Development. 239–252. Routledge, London. Padmanabhan, M. 2008. Sesame seed exports likely to take a hit. http://sify.com/finance/fullstory.php?id=14588746 Parker, J. 2009. Buying Farmland Abroad: Outsourcing’s Third Wave. The Economist. May 21. Pehanich, M. 2003. Market trends rising star: Frontera Foods Inc. http://www.preparedfoods.com/Articles/ Column/aacdffe5d2788010VgnVCM100000f932a8c0 Perlik, A. 2006. Sesame gulf shrimp. Restaurants and Institutions May 15, 116(10): 53. Petran, M. 2000. Sesame seeds. Restaurant Business 99(12): 1–2. Phillips, K.M., D.M. Ruggio and M. Ashraf. 2005. Phytosterol composition of nuts and seeds commonly consumed in the United States. Journal of Agricultural and Food Chemistry 53(24): 9436–9445. Pillsbury Bake-Off® Contest Winners Recipe Collection, Grand Prize and Hall of Fame Recipes. 1954. Open Sesame Pie, Dorothy Koteen. http://www.pillsbury.com/recipes/recipe-collections/Pillsbury-Bake-OffContest-Winners-Recipe-Collection.htm?WT.ac=HP_RecipeCollectionsLink3 Pitchford, P. 1993. Healing with Whole Foods: Oriental Traditions and Modern Nutrition. North Atlantic Books, Berkeley, California. Pitts, M., D. Dorling and C. Pattie. 2007. Oil for food: The global story of edible lipids. Journal of WorldSystems Research 13(1): 12–32. Prance, L. 2009. New product line covers all current skin care trends. www.cosmeticsdesign-europe.com/ Products-Markets/New-product-line-covers-all-current-skin-careRice, A. 2009. Is there such a thing as agro-imperialism? New York Times Magazine November 22: MM46 (New York edition). Rice vinegar and sesame oil: new line of seasoned vinegar and blended and pure sesame oils. Product Announcement. 2001. Prepared Foods 170(8): 47. Roberts, M. 2005. Food. New Statesman 24 Jan.: 56. Rubenstein, C. 2009. China’s eye on African agriculture. Asia Times online Oct. 2. http://www.atimes.com/ atimes/China_Business/KJ02Cb01.html Santos, W. 1995. Sesame oil supply dearth forces prices to escalate. Chemical Marketing Reporter 247(18): 10. Sarch, M.T. 1993. Case study of the farmer innovation and technology testing program in the Gambia. In Wellard, K. and J.G. Copestake, eds., Non-Governmental Organisations and the State in Africa: Rethinking Roles in Sustainable Agricultural Development. 225–238. Routledge, London. Saydut, A., M.Z. Duz, C. Kaya, A.B. Kafadar and C. Hamamci. 2008. Transesterified sesame (Sesamum indicum L.) seed oil as a biodiesel fuel. Bioresource Technology 99(14): 6656–6660. SeneGambia Development Assistance Program (DAP). 2002–2007. Sesame Production and Marketing, Opportunities and Challenges. DAP Challenges Series, CRS and USAID. Sesame: Threats and opportunities. 2006. Biodiversity International. http://www.bioversityinternational.org/ publications/publications/annual_report/article/article/sesame-threats-and-opportunities.html Shahidi, F., C. Liyana-Pathirana and D.S. Wall. 2006. Antioxidant activity of white and black sesame seeds and their hull fractions. Food Chemistry 99: 478-483. Shepherd, A.W. 2007. Approaches to linking producers to markets: A review of experiences to date. Agricultural Management, Marketing and Finance Service Occasional Paper 13. FAO, Rome. Shiva, V. 2000. Stolen Harvest: The Hijacking of the Global Food Supply. Zed Books, London. Shiva, V. 2002. Globalisation and the war against farmers and the land. Navdanya Shulman, M.R. 2009a. Recipes for Health: Roasted cauliflower with tahini-parsley sauce. New York Times October 21. http:// www.nytimes.com/2009/10/21/health/nutrition/21recipehealth.html?ref=fitnessandnutrition

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Regulatory 26 Current Status of Sesame and Its Commercial Products Dorothea Bedigian Contents Introduction..................................................................................................................................... 491 Pharmacopoeias.............................................................................................................................. 492 Labeling of Allergenic Ingredients................................................................................................. 492 Contact Dermatitis..................................................................................................................... 492 Allergy in Human Diet.................................................................................................................... 493 Recent Experimental Studies..................................................................................................... 493 Regulatory Aspects..................................................................................................................... 494 Salmonella Contamination.............................................................................................................. 495 Recalls........................................................................................................................................ 497 Aflatoxins and Other Fungal Contaminants.................................................................................... 498 Heavy Metals.................................................................................................................................. 499 Pesticides and Herbicides............................................................................................................... 499 Rodent Hairs, Fecal Matter, Insect Parts.........................................................................................500 Gras Status...................................................................................................................................... 501 Patents............................................................................................................................................. 501 Shatter-Resistant Sesame........................................................................................................... 501 Food and Food-Related Uses..................................................................................................... 502 Dietary Supplements, Nutraceutical and Pharmaceutical Use................................................... 502 Acknowledgments........................................................................................................................... 502 References....................................................................................................................................... 502

Introduction Sesame’s use in healing has been recognized and employed since antiquity (Bedigian 2000). Many reports in this volume show that sesame and its oil contain functional ingredients beneficial for their nutritional value as well as medicinal roles. Sesame should be encouraged in the diet for its anticarcinogenic and antioxidant activity. However, while incidence of them is rare, sesame allergens are a known disadvantage (Bedigian et al. 1985), as discussed in detail by Teuber, Chapter 8, in this volume. The literature shows that there are additional health concerns that require precautionary measures by commercial growers and processors. These include Salmonella and other bacterial contaminants, aflatoxins and other fungal contagions, heavy metals, especially lead, toxins, herbicides and pesticides, and zoological contaminants, such as insect parts, rodent hair, and fecal waste. These findings, while site-specific, are cautionary. Producers, aware of these sanitation issues, should consult with national health authorities and adopt appropriate safety procedures, and should certainly avoid 491

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attempting to circumvent necessary precautions. This summary illustrates issues requiring regulation of sesame in world markets; space limits prevent this review from being comprehensive.

Pharmacopoeias A search for sesame in the European Scientific Cooperative on Phytotherapy monographs led to Indian Medicinal Plants: An Illustrated Dictionary (Khare 2007): “Seeds – an important source of protein; rich in thiamine and niacine. Nourishing, lackagogue, diuretic, laxative, emmolient. Powdered seeds given internally in amennorrhoea and dysmenorrhoea. (Black seeds are preferred in Indian medicine.) Paste is applied to burns, scalds, piles. Leaves – used in affections of kidney and bladder. Bland mucilage is used in infantile diarrhoea, dysentery, catarrh and bladder troubles, acute cystitis and strangury.” “History and Lore of Sesame in Southwest Asia” (Bedigian 2004) contains references from early Arab, Armenian, and Greek compendia. “Sesame in Africa” (Bedigian 2003), assembled from scores of obscure references, details recent analyses and early usage in traditional African medicine. Bedigian, Chapter 24 in this volume, reviews records about sesame in early British and American pharmacopoeias. Hershenson’s comparison of the United States Pharmacopoeias from 1820 and 1960 intended to show which plant drugs have remained official and which were dropped during the 140-year span of the U.S.P. He reveals (1964) that sesame appears as Sesami Oleum on the secondary list of plants, as S. orientale in 1820, but as S. indicum in 1960. It appears again on a second table (1964): New Plant Additions U.S.P. xvi, as sesame oil, S. indicum. Raubenheimer (1910) defended the healing virtues of sesame oil steadfastly: “It is official in most of the foreign pharmacopoeias and has been admitted to the recently published pharmacopoeias, replacing olive oil in a great many galenical preparations. As it is recognized by the Ergänzungsbuch (supplement to the German Pharmacopoeia), it will undoubtedly become official in the new (5th) edition of the Arzneibuch. “The colonial addendum of the British Pharmacopoeia permits the use of sesame oil in India, the African Eastern and North American colonies, in the preparation of official liniments, ointments, and plasters for which the British Pharmacopoeia orders that olive oil should be used. Sesame oil has the following advantages over cottonseed and olive oil: 1. it does not readily turn rancid; 2. it is easily saponified even by cold process. … “I can, however, not agree with the decision of the old Revision Committee that sesame oil is antiquated and no longer in use. It has been official right along in a number of pharmacopoeias, it has been used officially and unofficially in the preparations of a large number of galenicals and has been admitted to all the recent pharmacopoeias. As I said before the British Pharmacopoeia sanctions the use of oil of Sesamum in place of olive oil in the British Colonies. Inasmuch as the revisers of the foreign pharmacopoeias are convinced of the value of this oil and in view of the many experiments, for a period of several years, which I and other pharmacists have made with oil of Sesamum in various galenical preparations, I sincerely hope that the present Revision Committee will consider the admission of this oil into the new U.S.P. and its use in several galenicals.”

Labeling of Allergenic Ingredients Contact Dermatitis There are warnings about sesame and its oil, externally (dermatological) and internally, concerning its allergens. FDA Regulations require that, where a food contains an allergenic ingredient or an ingredient originating from an allergenic ingredient, the food must be marked or labeled with a clear reference to the name of the allergenic ingredient concerned. By law, sesame must be labeled on pre-packed manufactured foods sold in Canada and the European Union (EU).

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The Material Safety Data Sheet (2008) about sesame oil includes it under Federal and State Regulations: TSCA 8(b) inventory, and on the European Inventory of Existing Commercial Chemical Substances. Toxicological information: “Toxic Effects on Humans: Slightly hazardous in case of skin contact (irritant), of ingestion, of inhalation.” Bedigian et al. (1985) discussed toxicological studies with sesamol that reveal proliferative lesions in rats fed sesamol: “Most were benign, two were malignant and two were questionable. A report (National Academy of Sciences 1973) on toxicants occurring naturally in foods states that one component of insecticidal synergism appears to be the placing of extra demands on the animal’s detoxification mechanism when they already have difficulty coping with the toxicant. The lignans of sesame oil are related to the hepatotoxin safrole that increases the incidence of the benign proliferative lesions in rats. In view of what is now known about the biological activity of sesamin and sesamolin as insecticidal synergists and antioxidants with an active methylenedioxyphenyl group, we question the use of sesame oil as a ‘control’ in pharmacological experiments. It no longer seems appropriate to view sesame oil as ‘inert’.” An early report (Kubo et al. 1986) described a case of contact sensitivity to the unsaponifiable substances in sesame oil in Denmark. An ointment composed of 60% sesame oil was used to treat a burn on the forearm. Ten days later, contact dermatitis developed. Examination revealed the allergens were sesamin and sesamolin, the unsaponifiable substances in sesame oil. Keskinen et al. (1991) announced a case of occupational asthma, rhinitis, and urticaria due to sesame seed, in a British male.

Allergy in Human Diet Sesame seeds are becoming an emerging global food allergy of a serious nature because of a high risk of systemic anaphylaxis (Chiu and Haydik 1991; James et al. 1991; Leatherhead 2002; Pecquet et al. 1998; Perkins 2001; Rubenstein 1950; Senti et al. 2000; Steurich 1989; Torsney 1964). In the early 21st century, new precautionary warnings were issued, such as “New Food Allergen Labeling Regulation: How Will It Affect You?” (Food and Health Network 2004), and “News on the Allergen Front” (2004).

Recent Experimental Studies Although a mouse model to study sesame anaphylaxis is desirable, currently it is not available. Using a transdermal exposure model system, Navuluri et al. (2006) tested the hypothesis that sesame seed elicits IL-4-associated IgE antibody response with consequent clinical sensitization in mice. Groups of BALB/c mice were exposed to sesame seed extract or saline or a control food (vanilla bean extract) by transdermal applications. Systemic IgE, IgG1, and IgG2a antibody responses were examined using preoptimized ELISA. Type 2 and type 1 cytokine responses were evaluated by ex vivo antigen-mediated activation of spleen cells. Clinical response to oral sesame challenge was studied. Western blot and N-terminal amino acid sequence analyses were performed to identify the sesame allergens. Transdermal exposure to sesame elicited robust IgE and IgG1 but very little IgG2a antibody responses. IgE response to transdermal exposure in two high-IgE responder mice strains with disparate MHC confirmed the intrinsic allergenicity of sesame seed. Transdermal sensitization was associated with activation of IL-4 but not IFN-γ. Furthermore, oral exposure to sesame resulted in clinical signs of systemic anaphylaxis. Western blot and sequence analysis identified four allergens, including Ses i 3 and the basic subunit of 11s globulins. These data argue that transdermal exposure to sesame seed can result in IL-4 activation, IgE response, and clinical sensitization for systemic anaphylaxis. Gangur et al. (2005) present a synopsis on the global prevalence, natural history, nature of the allergens, and immune mechanisms of sesame allergy. Evidence exists of the ability of protein and oil components of sesame to trigger immediate hypersensitivity via IgE antibody and delayed hypersensitivity via cell-mediated immune responses, respectively. There has been increased reporting of sesame allergy during the past five decades, mostly from developed

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countries. Clinically, most sesame allergy was presented in at least two major forms: (1) immediate hypersensitivity, often expressed as systemic anaphylaxis, associated with positive skin prick test and/or IgE antibody test results to sesame proteins with some cross-reactivity with other foods, and (2) delayed hypersensitivity to lignin-like compounds in sesame oil clinically expressed as contact allergic dermatitis. There were a few cases of immediate hypersensitivity to sesame with negative skin prick test and/or IgE antibody test results, confirmed by oral challenge tests. The authors conclude that sesame allergy is a significant, serious, and growing problem. Evidence exists of the ability of protein and oil components of sesame to trigger immediate hypersensitivity via IgE antibody and delayed hypersensitivity via cell-mediated immune responses, respectively.

Regulatory Aspects Caminiti et al. (2006) caution: “According to European Union (EU) food legislation, sesame, as an allergenic food, must be labeled when used as an ingredient in packaged foods. Nevertheless, the legislation does not take into account those foods sold as open (loose) products in restaurants, takeaways, and similar establishments, where ingredients may not be identifiable and cross-contamination may occur. Consequently, it is necessary that patients and physicians are also informed about lesser known allergenic foods. In addition, the legislation should be updated, following for instance the Swiss model, in order to make the declaration of possibly allergenic ingredients also compulsory in the case of freshly cooked foods.” The Food Allergy and Anaphylaxis Network (2002) reported the following regulatory measures by selected nations: “Labeling. Food Standards Australia New Zealand (FSANZ) regulates packaged and unpackaged foods in Australia and New Zealand. The FSANZ Food Standards Code 1.2.3 has been operational from December 20, 2002. Under the FSANZ Food Standards Code, crustaceans, egg, fish, milk, tree nuts, sesame seed, peanut, soy, gluten-containing cereals, and products derived from them must be named on the ingredient list at all times, without exception.” Canada (represented by Anaphylaxis Canada and Association Quebecoise des Allergies Alimentaires): “Common food allergens. Peanut, tree nuts (e.g., almond, hazelnut, cashew, walnut), soy, sesame seed, wheat, milk, egg, fish, shellfish, and sulfite (an additive).” Germany (represented by Deutscher Allergie- und Asthmabund e.V. [DAAB]): “Labeling. Germany follows the labeling regulations set by the European Union (EU) in EU Guideline 2003/89/EG. Since November 25, 2005, all packaged food that is produced in Germany has to follow the updated version of the food labeling regulations: 13 main food allergens must be listed: gluten-containing cereals, shellfish, fish, egg, peanut, soy, milk, tree nuts, celery, mustard, sesame seed, lupine and mollusks. Products derived from these allergens must be named without exception, if used as an ingredient. In addition, sulfite must be listed, if more than 10 mg/kg is used. If the legal name of the product identifies the use of an allergen, it does not need to be listed with the ingredients. If an ingredient derived from one of the main food allergens is considered free of any allergenic protein, it does not have to be listed (every exception is assessed by the European Food Safety Authority; e.g., glucose syrup from wheat starch). Food for direct consumption and loose products are not included in labeling regulations.” The Netherlands (represented by Nederlands Anafylaxis Netwerk): “Common food allergens. Peanut, milk, egg, wheat, tree nuts (e.g., almond, hazelnut, cashew, walnut), soy, fish, shellfish, and sesame seed.” “United Kingdom (represented by the Anaphylaxis Campaign) Common food allergens: Peanut, tree nuts (e.g., almond, hazelnut, cashew, walnut), sesame seed, fish, shellfish, egg, and milk.” The U.K. follows labeling regulations set by the European Union (EU). Sesame seeds must be declared in packaged foods. Kägi and Wüthrich (1993) warned: “With the increasing demand for vegetarian food the consumption of vegetable burgers as an alternative to beef burgers has now become widespread. Since products of this kind are often not provided with a clear description of their components or ingredients, potential allergens generally cannot be identified by the consumer. Their ingestion, however,

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may lead to severe allergic reactions in sensitized individuals. Here we describe nine systemic allergic reactions to sesame seeds that were diagnosed at the Allergy Unit, Department of Dermatology, Zurich, Switzerland between 1978 and 1991. In 1991 alone, we registered three cases of anaphylactic reaction to falafel vegetable burgers in patients allergic to sesame seeds. Falafel is an oriental specialty consisting of a wheat flour bun filled with chickpea balls. It is served together with a white sauce containing freshly ground sesame seeds. Our cases highlight the potential danger of vegetarian food and underline the importance of a proper allergologic assessment to recognize food allergy promptly so that the patient can eliminate the causative allergen and use suitable medication in the event of a dietary indiscretion.” In 2003, the U.K.’s Food Standards Agency prepared a summary report of findings; by 2004, the had drafted regulations for labeling, and listed sesame seeds and their derivatives (tahini and sesame oil) in Schedule AA1, along with cereals containing gluten, crustaceans, fish, eggs, peanuts, soybeans, milk, nuts (namely almond, hazelnut, walnut, cashew, pecan, Brazil nut, pistachio, macadamia nut, and Queensland nut), celery, mustard, and sulfur dioxide and sulfites at levels above 10 mg/kg or 10 mg/L expressed as SO2. The Agency’s Clear Food Labeling Best Practice Advice 12.2 recommended the use of simple language, e.g., providing the illustrative example “tahini (sesame).” The main points contained in current and impending EU labeling legislation include the types of ingredients that require allergen labeling and details on how each ingredient is described. To protect the health of consumers, they must be informed of the composition of foodstuffs through the ingredients listings on labels. In response to this, the European Council introduced Directive 2003/89/EC to require allergen labeling on certain foodstuffs. This was implemented throughout the U.K. starting November 25, 2005. This document is not a definitive interpretation of the law, which only the courts can provide. It is the responsibility of the individual businesses to ensure compliance with the law. There is the EU Directive 2003/89/EC, amending Directive 2000/13/EC regarding the indication of the ingredients present in foodstuffs, which makes additional allergen labeling a requirement on the labeling of all foodstuffs sold in the European Community. In England, this directive has been implemented by the Food Labeling (Amendment) (No.2) (England) Regulations 2004 and by parallel legislation in Scotland, Wales, and Northern Ireland. This will be enforced using powers and penalties given in the Food Safety Act 1990. All prepacked foods need to have the presence of any allergenic ingredients listed. This still applies even if the food or any of its ingredients were not required to be declared under the Food Labeling Regulations 1996. The regulations do not apply to foods sold loose or those prepacked for direct sale, that is, foods packed in the establishment from which they are sold. Allergen labeling became law in the United States in 2005. The statute Food Allergen Labeling and Consumer Protection Act amends Section 403 of the Federal Food, Drug and Cosmetic Act and is the result of years of work and cooperative efforts involving the food industry, the FDA, the Food Allergy and Anaphylaxis Network (FAAN), consumer advocacy groups, concerned families nationwide, and bi-partisan efforts by federal legislators such as senators Judd Greg (R-NH) and Edward Kennedy (D-MA). The new requirements are not unique to the United States. In 2003, the European Union issued a broader directive that requires food manufacturers to list twelve potentially allergenic ingredients and their derivatives, extending to other ingredients such as celery, mustard, sesame seed, and sulfites. Sesame allergy test kits became available (Eiamin 2005), and the FSA issued voluntary allergy labeling guidance (Fletcher 2006).

Salmonella Contamination The U.S. Food and Drug Administration (FDA) Compliance Guidance (2008) considers that “the primary pathogen of concern is Salmonella spp. The field should provide routine coverage for this pathogen.” Brockmann et al. (2004) found that sesame seed can be contaminated with Salmonella during growth, further storage, and processing. Irrigation and fertilization with manure and sludge, plant

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irrigation with surface water from streams, and animal droppings are potential sources of contamination. However, in sesame seed products in which the seed undergoes further treatment or processing, questions about the source of Salmonella contamination arises. Cross-contamination during the manufacturing process (by infected workers) is often mentioned; it can occur in isolated cases or in countries where minimal standard hygiene conditions are not always maintained during production, but it seems unlikely to the authors that contamination occurs regularly during processing, for several reasons. High temperatures (>120ºC) and the inclusion of sugar in the production process, as in halvah, at this stage minimize the risk. Contamination resulting from improper hygiene during packaging or transport would lead to the contamination of single jars rather than of entire lots. The authors’ finding that several products as well as the raw sesame seed from different countries were contaminated makes it more likely that contamination happened during harvesting. During the same outbreak investigation, Salmonella was isolated in Australia from halvah produced in Lebanon. Furthermore, the National Enteric Pathogen Surveillance Scheme in Australia has recorded the isolation of 17 Salmonella spp. from sesame seeds and sesame seed products, including hummus, tahini, and halvah, between 1985 and 2001. They assert that Salmonella contamination of sesame seed seems to be a more urgent problem than previously thought. Food microbiologists and public health professionals were made aware of this and now highlight the importance of hygiene, especially during harvest. Unicomb et al. (2005) described sesame seed products contaminated with Salmonella, especially three outbreaks associated with tahini: “In November 2002, the first of three outbreaks of Salmonella montevideo infection in Australia and New Zealand was identified in New South Wales, Australia. Affected persons were interviewed, and epidemiologically linked retail outlets inspected. Imported tahini was rapidly identified as the source of infection. The contaminated tahini was recalled and international alerts posted. A second outbreak was identified in Australia in June–July 2003 and another in New Zealand in August 2003. In a total of 68 S. montevideo infections, 66 cases were contacted. Fifty-four (82%) reported consumption of sesame-seed-based foods. Laboratory analyses demonstrated closely related PFGE patterns in the S. Montevideo isolates from human cases and sesame-based foods imported from two countries. On the basis of our investigations sesame-based products were sampled in other jurisdictions and three products in Canada and one in the United Kingdom were positive for Salmonella spp., demonstrating the value of international alerts when food products have a wide distribution and a long shelf life. A review of the controls for Salmonella spp. during the production of sesame-based products is recommended.” The venerated U.S. tahini and halvah manufacturer Joyva Corporation, Brooklyn, New York (Richard Radutzky, pers. comm. Jan 28, 2008), displayed their mandatory sanitary certification procedures. Prior to packaging for shipping, every lot of tahini is inspected and certified by an external testing service, Silliker Labs, Allentown, Pennsylvania, for Salmonella, Staphylococcus, and Listeria. An increase in hummus consumption fuels demand for tahini. The New Zealand Food Safety Authority (NZFSA) Discussion document “Case Study: Sesame Seed-based Products” (2004) found: “In July 2003, Egyptian tahini paste (a sesame-seed product used in Middle Eastern foods) was tested by a food business as part of preliminary hazard identification for the introduction of a food-safety programme. Salmonella montevideo was isolated and the recall of over 3 tons of tahini sauce resulted. In August 2003, Environmental Science and Research confirmed a cluster of nine cases of Salmonella montevideo infection. Both tahini paste and halvah (a confection made with tahini paste) were found to be contaminated with S. montevideo. Food Safety Australia New Zealand recalled 3 product lines, and in September 2003 NZFSA introduced an emergency food standard for tahini and halvah, mandating sampling of the products at the border. Both implicated brands had been sampled by ESR prior to the outbreak as part of a microbiological survey of tahini-based food products, but were not found to be contaminated. This sampling was prompted by an Australian warning in July 2001 against consumption of two imported brands of halvah believed to have been responsible for a number of cases of infection caused by Salmonella typhimurium DT104.since 1993,l there have been 128 confirmed cases of S. montevideo infection in New Zealand. They represent up to 2.4% of the annual number of human

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Salmonella cases notified during that period. Although Salmonella infection from other serotypes may also be due to contaminated imported foods, these data suggest that imported foods account for only a small proportion of salmonellosis in New Zealand.” This report cites Unicomb et al. (2003) and ESR, “A Report on Tahini and Tahini-based Products,” May 2002, ESR, Porirua. Note that in 2009 the NZFSA regulatory authority changed. Standard Management Rule 22, Tahini or crushed sesame seeds or any products containing these, dictates: “From the 1st July 2009, NZFSA replaced this SMR with a standardized format for all Imported Food Requirements. Made obsolete; refer to the Imported Food Requirement for tahini or crushed sesame seeds or any products containing these.” The new regulations 2.0 require “Importer Clearance Options”:

2.1 The requirements in this document apply to crushed sesame seed products and are in addition to clearance requirements detailed in the Import Clearance Procedure. 2.2 Importers must also meet the requirements of the Food (Importer Listing) Standard 2008 and the Food (Importer General Requirements) Standard 2008. Importers should also read and understand the Food Importer Standards Guidance before sourcing products to import. 2.3 For crushed sesame seed products, importers have a responsibility under the Food (Importer General Requirements) Standard 2008 to ensure imports are not contaminated with Salmonella. Tahini and crushed sesame seed products are at high risk of contamination during processing (crushing and packaging). Good manufacturing practices during processing can greatly reduce the likelihood of Salmonella contamination. Tahini and crushed sesame seed pastes do not normally receive a heat treatment prior to consumption, which would inactivate the pathogenic bacteria. 2.4 The following two options are available to importers when they are aiming to satisfy a Food Act Officer that the food complies with the Food Act and can therefore be cleared: Option 1 – Clearance sampling and testing on arrival in New Zealand. In the absence of a multiple release permit (MRP), products are sampled and tested in New Zealand. Products will be tested for Salmonella, in accordance with NZFSA’s sampling and testing protocol. Option 2 – Multiple Release Permit (MRP) MRPs are issued for imported food products that are: • Inadvertently captured by the tariff codes monitored by the NZFSA, and /or • From particular suppliers under an arrangement agreed to by the importer and NZFSA. Al-Hooti et al. (1997) illustrate the level of precautionary quality control in Kuwait in the case of date bars fortified with almonds, sesame seeds, oat flakes, and skim milk powder. Fortified date bars were prepared from some of the commonly grown date cultivars in the United Arab Emirates. The ash and protein contents increased, but the fat content decreased slightly with the inclusion of skim milk powder in the remaining date bar formulations. All the date bars sampled were free from Enterobacteriaceae and coliforms.

Recalls The FDA posts press releases and other notices of recalls and market withdrawals by the firms involved as a service to consumers. For example: “(San Leandro, CA, May 25, 2007) nSpired Natural Foods of San Leandro, California is voluntarily recalling all MaraNatha Sesame Tahini in 16-oz sizes with a Use By Date of 04/11/08 and earlier, and 15-lb and 32-lb sizes with an expiration date of 01/05/08 (lot 07130) and earlier, because it has the potential to be contaminated with Salmonella, an organism which can cause serious and sometimes fatal infections in young children,

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frail or elderly people, and others with weakened immune systems. Healthy persons infected with Salmonella often experience fever, diarrhea (which may be bloody), nausea, vomiting and abdominal pain. In rare circumstance, infection with Salmonella can result in the organism getting into the bloodstream and producing more severe illnesses such as arterial infections (i.e., infected aneurysms), endocarditis and arthritis. MaraNatha Sesame Tahini was distributed nationally through distributors, retail stores, and comes in a 16-oz glass jar, and 15-lb and 32-lb pails. Products affected are Organic Raw Sesame Tahini, Organic Roasted Sesame Tahini, Natural Raw Sesame Tahini and Natural Roasted Sesame Tahini. There have been no confirmed cases of illness to date. Potential salmonella contamination was discovered during routine, random sample testing by the Canadian Food Inspection Agency. As a result, the company is voluntarily recalling this product as a precautionary measure and has put additional safety measures in place.” Similarly, in 2007 the largest U.S. natural food store, Whole Foods Market, recalled sesame butter for possible Salmonella and issued a nationwide recall of 365 Organic Everyday Value Sesame Tahini. Professional Liability Insurance Services, Inc. (2007) reported the following Salmonella recalls in the U.K.: “Damasgate Wholesale Recalls Sesame Seed Paste Halvah; ... Sesame seeds and seed mix.” The Association of Food, Beverage and Consumer Products Companies (2009) includes concern about Salmonella in low-moisture foods. Its Salmonella Control Guidance search of the EU pathogen alert system showed that Salmonella has been detected in coriander, dehydrated onions, dried mushrooms, sesame seeds, dried sage, spices, and soybean meal (Betts 2007). A review of recall records at FDA by Vij and colleagues (2006) showed that from 1970 to 2003 there were 21 recalls involving spices and herbs contaminated with Salmonella. Sixteen of these recalls occurred during 2001–2004, and 12 of these recalls involved spices imported from around the world (India, Spain, Turkey, Egypt, Jamaica, Mexico, and Taiwan). The spices in these recalls included ground black pepper, ground cumin, ground oregano, paprika, red pepper powder, ground sage, sesame seeds, ground thyme, and dried basil leaves (Vij et al. 2006).

Aflatoxins and Other Fungal Contaminants Yentür et al. (2006), using high-performance liquid chromatography (HPLC), analyzed 20 packages of sesame and 20 cans of peanut butter collected from local Ankara markets. Their data revealed that while aflatoxin levels found in sesame samples were within the Turkish Food Codex values, the levels found in peanut butter were excessive. There was no investigation, however, of aflatoxin levels in tahini, sesame paste, which would have provided a more unequivocal comparison. Earlier, Nilüfer and Boyacioglu (2002) compared three methods: HPLC, fluorometry, and enzyme-linked immunosorbent assay (ELISA). Their survey demonstrated the need for control of aflatoxin contamination of foodstuffs involving sesame seeds as an ingredient. Li et al. (2009) conducted a study on the natural occurrence of aflatoxins in Chinese peanut butter and sesame paste samples and found 32% of sesame paste samples contained aflatoxin B1 levels higher than Chinese and EU regulations. Seven sesame paste samples were declared positive, based on EU and Chinese regulations, rejected, and banned, with an uncertainty level of 40%. Seeking to balance health benefits with the potential trade disruptions that regulations can cause is their issue of concern. Previously, Jonsyn (1988) sampled the mycoflora of sesame seeds from four geographic locations in Sierra Leone. Three toxigenic Aspergillus species, A. flavus Link ex Fries, A. ochraceus Wilhelm, and A. tamarii Kita, were common to all samples. Penicillium citrinum Thom and two Fusarium spp. were found in samples from two localities. The mycotoxins aflatoxin B1 and G1, ochratoxin A and B, and citrinin occurred too. Later Jonsyn (1990) sampled a local specialty, ogiri, made of fermented sesame seeds, widely used locally as a condiment. She also examined the various ways the finished product is marketed and stored. Three common methods for wrapping ogiri were with dried banana leaves, fresh or smoked leaves of Newbouldia laevis Seem., and plastic wraps. Fungi do not participate in the ogiri fermentation process but do contaminate the product. Aspergilli and Penicillia were more pronounced when improper processing, handling, and storage occurred. The

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use of clean dry nylon fiber bags to ferment the product, coupled with periodic smoking during and after fermentation, proved very effective controls. Samples wrapped in dry banana leaves were less likely to be contaminated, especially with regular smoke treatment. Ogiri samples in tight plastic wraps had longer shelf life even without smoking.

Heavy Metals Angelova et al. (2004) set out to ascertain the level of pollution and the way the heavy metals enter oil crops near a smelter in Bulgaria. “Soil and plants were sampled at different distances from the source of pollution, the Non-Ferrous-Metal Works (NFMW) near Plovdiv (0.5 and 15 km). The contents of the heavy metals in the plant material (roots, stems, leaves, seeds, fruit shell) and sunflower oil and rapeseed oil were determined.” An inductively coupled plasma emission spectrometer was used to make quantitative measurements. “Peanuts (Arachis hypogaea L.) were the crop with the highest uptake of heavy metals from the soil, followed by rapeseed (Brassica napus L.), sesame (Sesamum indicum L.), and sunflower (Helianthus annuus L.). The distribution of heavy metals in the organs of the crops had a selective character that in peanuts decreased in the following order: roots > stems > leaves > fruit shell > seeds; in sunflower—leaves > roots > stems > seeds > fruit shell; and in sesame and rapeseed—leaves > stems > roots > fruit shell > seeds. A clearly distinguished tendency toward a decrease of the contents of heavy metals in oil crops was observed with increasing of the distance away from the NFMW. The quantities of lead (Pb), copper (Cu), and cadmium (Cd) in the rapeseed oil obtained from rapeseed grown 0.5 km away from the NFMW, were higher than the accepted maximum permissible concentrations. In the oil from sunflower grown in the region of the NFMW, the contents of Pb and Cu exceeded about two times the maximum permissible concentration and could be hazardous for people to consume it. Sunflower and rapeseed could be grown in industrially polluted regions until stage ‘blossoming’ and be used for fodder for the animals.” A study of occurrence of lead in sesame paste still has significance today. Yannai and Haas (1973) found that the sesame plant has an unusual capacity for lead accumulation from the soil into the seeds. The lead content of sesame paste was somewhat higher than that of seeds. The maximum acceptable load of lead from food set by a FAO/WHO Expert Committee on Food Additives (1967) was 0.005 mg/kg body weight/day, a fact that has consequences for populations that rely heavily of sesame paste as a food staple. Angelova et al. (2005) viewed sesame a “moderate lead accumulator.” Pappa et al. (2006) tested the total selenium content of foods purchased from local markets in the northwestern part of Greece using hydride generation atomic fluorescence spectroscopy. The results of this study were within the range from other countries. The overall mean average of selenium concentration of the foods examined, in decreasing order, was found in sesame seeds (783.1 ng g-1), fish (246 ng g-1), legumes (162.5 ng g-1), eggs (123 ng g-1), bread (91.9 ng g-1), meat (71.7 ng g-1), cheese (69.8 ng g-1), yoghurt (23.6 ng g-1), nuts (19.6 ng g-1), milk (15.4 ng g-1), vegetables (6.5 ng g-1), and fruits (3.4 ng g-1). Considering the average daily individual consumption of these foods by Greeks, the average daily dietary intake of selenium supplied by this source is 39.3 µg per capita.

Pesticides and Herbicides Bhatnagar and Gupta (1998) discovered from their studies in Rajasthan that lindane residues persisted both in seed and oil of sesame. At the lower dose of 500 g active ingredient (a.i.)/ha, the residues were within tolerance level, while at the higher dose the residues were above the maximum residue limit (MRL) (0.05 ppm) both in seed and oil. At Kanpur, the residues of lindane persisted in oil above MRL at both the doses: 500 and 1000 g (a.i.)/ha. The sesame seed and oil showed chlor­ pyriphos residues at both the 0.39 and 0.56 mg kg-1 treatments. Sesame seed showed chlorpyriphos residues at 500 and 1000 g a.i./ha while the corresponding values of residues in oil were 0.95 and 1.30 mg kg-1. These values were above the MRL (0.05 ppm) of chlorpyriphos in oil seeds.

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Om et al. (1998) in “Pesticide Residues in Marketed Sesame” investigated the contamination in seven varieties of domestic and imported sesame purchased from sesame marketed in Seoul, Korea. This data obtained may provide basal information about re-evaluation and establishment of the level of pesticide residues for public health interest. Three pesticides, benomyl, mancozeb, and metalaxyl, are the major fungicides of sesame cultivation. Metalaxyl residues were detected in sample B (imported sesame) and F (Yecheon sesame) at 0.014 ppm and 0.04 ppm, respectively. Metalaxyl, commercially named Ridomil or Metasyl, belongs to the acylalanine family. FAO/WHO (1987) reported the maximum residue limit (MRL) of metalaxyl in soybeans (0.1 ppm), cotton seed oil (0.05 ppm), and peanuts (0.1 ppm), while the Pesticide Chemical News Guide determined levels in cotton seed oil (0.1 ppm) and peanuts (0.2 ppm). However, owing to its low consumption in Western countries, the MRL of metalaxyl in sesame was not established. Considering these MRLs, the authors viewed the metalaxyl residues of imported and Yecheon sesame in their study as significant amounts, and recommended on the basis of this study, which detected metalaxyl residue in sesame, that the Korean Ministry of Health and Social Affairs should determine and establish the allowance limit of metalaxyl residue for food safety and public health. The Korea Food and Drug Administration (2003) issued Notice #2003-108, Proposed Revision of Food Standards and Specifications, revising the MRL of the pesticides chlorothalonil and fluazifop-butyl on sesame. Gebreegzi et al. (2000) reported a method used for the simultaneous analysis of carbaryl, malathion, fenitrothion, and diazinon residues in sesame seeds obtained from an Ethiopian field crop that had been treated with the pesticides during its growing period. It appears that any residues present after the last application had declined to levels below the detection limit by harvest time. Although no information is available on the MRLs of the pesticides under study in the sesame crop, it is worth noting that the Joint FAO/WHO Meeting of Experts on Pesticide Residue recommended the MRL guideline levels of 1 to 20 µg/g of carbaryl, malathion, fenitrothion, and diazinon in grain and milled products from grain. According to the FDA, sesame seed and oil are among exempted products in the category “Pesticides of a character not requiring FIFRA regulation, Code #152.25.” The Pesticide Action Network North America (n.d.) report “Sesame oil: Identification, Toxicity, Use, Water Pollution Potential, Ecological Toxicity and Regulatory Information” indicates: “Not toxic in any category so far as data reported.” However, the Japanese Health, Labor and Welfare Agency (2009) found sesame from China in violation by presence of the pesticide dicofol; it placed all products in quarantine and requested China’s Health, Labor and Welfare department to inspect sesame seeds and their processed products. Beyer and Biziuk’s (2008) review of current analytical techniques for analyses of food contaminants cites Papadakis et al. (2006) to check for organochlorine pesticide residues in sesame seeds. Carson (2009) announced in “Section 18 Crisis Emergency Exemption Allows Sesame Growers to Use Herbicide”: “Oklahoma Secretary of Agriculture, Terry Peach, received permission for state sesame growers to apply a restricted use herbicide, Dual Magnum®, as a pre-emergent. The chemical is an important tool for weed control but must be applied before the sesame plants emerge. ‘Sesame production is increasing in Oklahoma with about 50,000 acres expected to be planted this year,’ he said. ‘Our growers have asked for this herbicide and we were pleased we were successful in receiving this exemption.’ Growers have only 15 days to apply and may begin using the chemical immediately” (dated May 22, 2009). The German Pesticide Action Network prepared the “Field Guide to Non-chemical Pest Management in Sesame Production” (Bissdorf 2007), which offers valuable guidance about alternative practices, and aimed toward farmers in emerging markets.

Rodent Hairs, Fecal Matter, Insect Parts The FDA (2005) defined “the criteria for direct reference seizure to Division of Compliance Management and Operations (HFC-210) and for direct citation by the District Offices, ‘Insect Filth

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and Decomposition’: The sesame seeds contain an average of 5% or more insect infested or decomposed seeds by weight; or Mammalian Excreta: The sesame seeds contain an average of 5 milligrams or more of excreta per pound; or Foreign Matter: The sesame seeds contain an average of 0.5% or more foreign matter by weight … Article (sesame seeds) adulterated (when introduced into and while in interstate commerce) (while held for sale after shipment in interstate commerce), within meaning of 21 U.S.C. 342(a)(3), in that it consists wholly or in part of a filthy substance by reason of presence therein of (insects), (insect webbing), (insect excreta), (insect damaged sesame seeds), and (mammalian excreta); and that it consists in part of a decomposed substance by reason of presence therein of (moldy, decomposed sesame seeds); and is unfit for food by reason of presence therein of (stones), (clay), and (sand); or 342(b)(2) in that (stones), (clay), and (sand) have been substituted wholly or in part for sesame seeds.” The FDA Import Alert (2009) lists import products detained without physical examination and receiving surveillance, owing to insect or animal filth contamination, from Guatemala, India, Mexico, and the People’s Republic of China during the past two decades. The FDA Guidance, Compliance and Regulatory Information (2009) defines as a defect in sesame seeds an “average of 5 mg or more of mammalian excreta per pound, post harvest and/or processing animal contamination”; insect filth: “average of 5% or more seeds by weight are insectinfested or damaged pre-harvest and/or post harvest and/or processing infestation”; mold: “average of 5% or more seeds by weight are decomposed pre-harvest infection”; foreign matter: “average of 0.5% or more foreign matter by weight, post processing and/or processing contamination.” Michels and Shroff (1996) listed earlier Compliance Policy guidelines.

Gras Status Sesame is widely used in human food and medicine, as it has GRAS (Generally Recognized as Safe) status (National Archives and Records Administration 2009). The CRC Handbook of Food Additives, 2nd ed., (Furia 1980) identifies sesame as GRAS, natural flavor, in FDA §121.101. The “Final Report on the Safety Assessment of Sesame Oil” (1993), a clinical assessment of sesame oil, concluded that “sesame oil is safe as a cosmetic ingredient in the present practices of use.” Smolinske described its regulatory classification (1992): “Sesame oil is an oleaginous vehicle in pharmaceuticals. Unsaponifiable fraction contains sesamol, sesamolin, sesamin, not more than 1.5% of pharmaceutical grade oil, present in 50 pharmaceutical products registered with FDA. There are also several oral capsules, concentrates, emulsions, tablets, topical creams containing this excipient, used as solvent and skin and hair conditioner in cosmetics: eye makeup, lipsticks, makeup foundation, hand and body cream and lotions.” However, Anton et al. (1974), analyzing sesame oil as a carrier oil, warned: “Sesame oil, a vehicle we used to solubilize tetrahydrocannabinol for chronic oral administration to mice, unexpectedly reduced norepinephrine in the brain, heart and spleen. This indicates that some solubilizing agents (at least sesame oil) may not be pharmacologically inert.” Presently, the National Archives and Records Administration (2009) Electronic Code of Federal Records lists sesame seed as “generally recognized as safe.”

Patents These are a few representative patents related to sesame capsule shatter resistance, food, and pharmaceutical applications for illustration; it is beyond the scope of this chapter to identify all.

Shatter-Resistant Sesame Langham, D.R. 2009. Non-Dehiscent Sesame Variety Sesaco 32. SESACO, San Antonio, Texas. Patent 20090222939.

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Food and Food-Related Uses Ishigaki, R. 1999. Fermented sesame having antioxidative properties, and food containing the same. Yugengaisha SOI. Patent 5891492. Osawa, T., K. Nagai and K. Shibuya. 1999. Protein composition derived from sesame seed and use thereof. Takemoto Yushi Kabushiki Kaisha. Patent 5993795. Shinmen, Y., K. Akimoto, S. Asami, Y. Suwa, Y. Kitagawa, M. Sugano, H. Yamada and S. Shimizu. 1993. Liver function improver. Suntory, Ltd. Patent 5211953. Silkeberg, A. and S.P. Kochhar. 2000. Refining of edible oil retaining maximum antioxidative potency. Lipidia Holding S.A. Patent 6033706.

Dietary Supplements, Nutraceutical and Pharmaceutical Use Benecke, H.P. and B.E. Sherwood. 1984. Sesamin as a psychotropic agent, for alleviating the symptoms of alcohol and tobacco withdrawal: tranquilizing, anti-depressant, anti-convulsant effects. The Vinoxen Company, Inc. Patent 4427694. Forse, R.A. and S. Chavali. 1998. Anti-inflammatory and infection protective effects of sesamin-based lignans. Beth Israel Deaconess Medical Center, Inc. Patent 5762935. Namiki, M., T. Osawa, Y. Fukuda and T. Ozaki. 1987. Lignan compound. Takemoto Yushi Kabushiki Kaisha. Patent 4649206. Namiki, M., T. Osawa, Y. Fukuda and T. Ozaki. 1987. Method of producing phenol-type natural antioxidative materials from processed sesame seed products. Takemoto Yushi Kabushiki Kaisha. Patent 4708820. Namiki, M., T. Osawa, M. Isobe and Y. Fukuda. 1988. Method of producing active antioxidant. Takemoto Yushi Kabushiki Kaisha. Patent 4774343. Namiki, M., T. Kobayashi and H. Hara. 2001. Process of producing sesame lignans and/or sesame flavors. Kabushikikaisha Fujimiyohoen. Patent 6278005. Sugiura, M., M. Inayoshi and S. Sakurai. 1999. Method of separating sesamin analogues. Takemoto Yushi Kabushiki Kaisha. Patent 5902458.

Acknowledgments Appreciation to librarians who provided professional support for this research, in particular the Leonard Lief Library, Lehman College, City University of New York (CUNY); Olive Kettering Library at Antioch College, Yellow Springs, Ohio; and the Science Information and Business Library Branch, New York Public Library. Richard Radutzky of Joyva Corporation, Brooklyn, New York, welcomed me twice to tour their spotless facility, to take photographs, and answer my many questions about processing sesame.

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