Tropical Fruits [Volume 2, 2 ed.] 9781845939342

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CROP PRODUCTION SCIENCE IN HORTICULTURE SERIES Series Editor: Jeff Atherton, Professor of Tropical Horticulture, University of the West Indies, Barbados This series examines economically important horticultural crops selected from the major production systems in temperate, subtropical and tropical climatic areas. Systems represented range from open field and plantation sites to protected plastic and glass houses, growing rooms and laboratories. Emphasis is placed on the scientific principles underlying crop production practices rather than on providing empirical recipes for uncritical acceptance. Scientific understanding provides the key to both reasoned choice of practice and the solution of future problems. Students and staff at universities and colleges throughout the world involved in courses in horticulture, as well as in agriculture, plant science, food science and applied biology at degree, diploma or certificate level will welcome this series as a succinct and readable source of information. The books will also be invaluable to progressive growers, advisers and end-product users requiring an authoritative, but brief, scientific introduction to particular crops or systems. Keen gardeners wishing to understand the scientific basis of recommended practices will also find the series very useful. The authors are all internationally renowned experts with extensive experience of their subjects. Each volume follows a common format covering all aspects of production, from background physiology and breeding, to propagation and planting, through husbandry and crop protection, to harvesting, handling and storage. Selective references are included to direct the reader to further information on specific topics.

Titles Available: 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23.

Ornamental Bulbs, Corms and Tubers A.R. Rees Citrus F.S. Davies and L.G. Albrigo Onions and Other Vegetable Alliums J.L. Brewster Ornamental Bedding Plants A.M. Armitage Bananas and Plantains J.C. Robinson Cucurbits R.W. Robinson and D.S. Decker-Walters Tropical Fruits H.Y. Nakasone and R.E. Paull Coffee, Cocoa and Tea K.C. Willson Lettuce, Endive and Chicory E.J. Ryder Carrots and Related Vegetable Umbelliferae V.E. Rubatzky, C.F. Quiros and P.W. Simon Strawberries J.F. Hancock Peppers: Vegetable and Spice Capsicums P.W. Bosland and E.J. Votava Tomatoes E. Heuvelink Vegetable Brassicas and Related Crucifers G. Dixon Onions and Other Vegetable Alliums, 2nd Edition J.L. Brewster Grapes G.L. Creasy and L.L. Creasy Tropical Root and Tuber Crops: Cassava, Sweet Potato, Yams and Aroids V. Lebot Olives I. Therios Bananas and Plantains, 2nd Edition J.C. Robinson and V. Galán Saúco Tropical Fruits, 2nd Edition Volume 1 R.E.Paull and O. Duarte Blueberries J. Retamales and J.F. Hancock Peppers: Vegetable and Spice Capsicums, 2nd Edition P.W. Bosland and E.J. Votava Raspberries R.C. Funt

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TROPICAL FRUITS, 2ND EDITION, VOLUME II

Robert E. Paull Tropical Plant and Soil Sciences University of Hawaii at Manoa Honolulu, HI, USA and Odilo Duarte Retired Professor - Escuela Agrícola Panamericana El Zamorano, Honduras Now: Professor and Lead Scientist in Agribusiness CENTRUM Católica Business School Pontificia Universidad Católica del Perú, Lima, Perú

CABI is a trading name of CAB International CABI CABI 875 Massachusetts Avenue Nosworthy Way 7th Floor Wallingford Cambridge, MA 02139 Oxfordshire OX10 8DE USA UK T: +1 800 552 3083 (toll free) T: +1 (0)617 395 4051 E-mail: [email protected]

Tel: +44 (0)1491 832111 Fax: +44 (0)1491 833508 E-mail: [email protected] Website: www.cabi.org

© R.E. Paull and O. Duarte 2012. All rights reserved. No part of this publication may be reproduced in any form or by any means, electronically, mechanically, by photocopying, recording or otherwise, without the prior permission of the copyright owners. A catalogue record for this book is available from the British Library, London, UK. Library of Congress Cataloging-in-Publication Data Paull, Robert E. Tropical fruits / Robert E. Paull and Odilo Duarte. -- 2nd ed. p. cm. -- (Crop production science in horticulture series ; no. 20) Includes bibliographical references and index. ISBN 978-1-84593-672-3 (alk. paper) 1. Tropical fruit. I. Duarte, Odilo. II. C.A.B. International. III. Title. IV. Series: Crop production science in horticulture ; 20. SB359.P38 2011 634’.6--dc22 2010016776 ISBN-13: 978 1 84593 789 8

Commissioning editor: Sarah Hulbert Editorial assistant: Chris Shire Production editor: Simon Hill Typeset by Columns Design XML, Reading. Printed and bound in the UK by MPG Books Ltd.

CONTENTS

PREFACE

vii

ACKNOWLEDGEMENTS

ix

1 ANNONAS: SOURSOP AND ROLLINIA

1

2 BREADFRUIT, JACKFRUIT, CHEMPEDAK AND MARANG

25

3 CARAMBOLA AND BILIMBI

53

4 DURIAN

75

5 GUAVA

91

6 MANGOSTEEN

123

7 RAMBUTAN AND PULASAN

139

8 PASSION FRUIT AND GIANT PASSION FRUIT

161

9 PALMS

191 v

vi

Contents

10 OTHER AFRICAN FRUIT: TAMARIND, MARULA AND ACKEE

223

11 OTHER TROPICAL ASIAN AND PACIFIC FRUIT

255

12 AMERICAN FRUIT

303

INDEX

363

PREFACE

Volume I presented the general aspects of tropical fruit production and covered the major tropical fruit in international trade such as banana, pineapple, papaya, mango and avocado. Many other tropical fruit, already well-known in the tropics, are now appearing in larger temperate city markets. In this volume, we have selected those that are being increasingly seen in overseas markets outside of the tropics. The choice of crops to present in Volume II was the greatest challenge, especially in the last three chapters dealing with other Asian and Pacific, African and American Fruits. The fruit crops covered in these last three chapters is the tip of what is available and that have considerable potential as fruit crops. A number of the chapter fruit sections show the significant gaps in our knowledge of managing these fruit crops in large orchards and not backyard production. A major gap is lack of breeding effort to develop varieties suitable for intensive production that have disease and insect resistance, high yield and desired fruit quality that suit different growing environments and consumer markets. We have followed the same chapter layout used in the first edition and Volume I of this edition. The information in each fruit chapter deals with taxonomy, varieties, propagation and orchard management, biotic and abiotic problems, variety development and postharvest handling. The information contained should be of use to all readers and students interested in an introductory text on tropical fruit production. Many have contributed to the endeavour. Encouragement and help of Henry in this passion came from many and acknowledged in the First and Second Editions. Numerous comments and suggestions from colleagues have been incorporated. All errors and omissions are our responsibility. The illustrations of many of the crops covered in this Volume and for Volume I were done by Susan Monden in Honolulu. The family of Dr. Jorge Leon granted us permission to use the figures from ‘Botánica de los Cultivos Tropicales’. Dr. Lionel Robineau, coordinator TRAMIL gave us permission vii

viii

Preface

to use the Hylocereus drawing and Dr. Mike Nagao the use of the Pulasan picture. Mrs. Meg Coates Palgrave kindly agreed to let us use the Marula drawing from Trees of Central Africa though we are unable to render it in colour. The editor of Flore Analytique du Bénin let us use the ackee drawing. Thanks are also due to the Commissioning Editor Sarah Hulbert and Christopher Shire at CABI for their assistance and patience during the book’s development. We would greatly appreciate receiving all comments and suggestions on this text. We can be reached at the address in the front of the text or via E-mail at [email protected] or [email protected]. In closing, we both acknowledge the continued support, assistance, and love of our wives Nancy and Carla, and our children that enabled us to complete this undertaking. Robert E. Paull Honolulu, USA. 2012 Odilo Duarte Lima, Peru. 2012

ACKNOWLEDGEMENTS

The authors gratefully acknowledge the support, information, and ideas supplied by Jeff Anderson, Alton Bailey, Jit Baral, Lou Biad, Chris Biad, Anna Biad, Judy Bosland, Emily Bosland, Will Bosland, Emma Jean Cervantes, Danise Coon, Deyuan Wang, Natalie Goldberg, Max Gonzalez, Wendy Hamilton, Steve Hanson, John Hard, Sue Hard, Jaime Iglesias, Sanjeet Kumar, Jimmy Lytle, Jo Lytle, Ariadna Monroy, Mary O’Connell, Jaebok Park, Jennifer Randall, Adrian Rodriquez, Robert Steiner, Ousmane Sy, Betty Terrien, Nankui Tong, Manju Vishwakarma, Stephanie Walker, April Ulery, Everardo Zamora, and the Chile team at New Mexico State University.

ix

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1 ANNONAS: SOURSOP AND ROLLINIA

BOTANY Family Both soursop and Rollinia belong to the Annonaceae, commonly referred to as the custard-apple family. The family consists of about 75 genera that are now widely distributed. Some Annona species are grown as ornamentals, while others are known for their edible fruit and perfume.

Important genera and species The soursop belongs to the most important genus Annona, which among its more than 100 species has seven species and one hybrid that are grown commercially worldwide. Soursop is the most tropical of these species and has the largest fruit. Rollinia (or biriba) belongs to the closely related genus Rollinia and it is not as well known as soursop. The two most important commercial species are cherimoya and sweetsop. Along with the hybrid, atemoya, all three are discussed in Chapter 6 of Volume 1. Annona muricata L. is known as soursop in English and guanábana in most Spanish-speaking countries. It is also known as catoche (Venezuela), zapote agrio, zapote de viejas or cabeza de negro (Mexico), guayabano (Philippines), nangka belanda zuurzak or sisrsak (Indonesia), thurian-khaak (Thailand), sitaphal (India), fruta de conde, graviola, jaca do Pará (Brazil), nona sri kaya or durian belanda (Malaysia) and corossol epineux (France). The synonyms for Rollinia mucosa (Jacq.) Baill. are R. orthopetala A. DC. or R. deliciosa Saff., R. pulcherrima A. DC. and Annona mucosa Jacq. (Sousa, 2008). Other names are biribá, fruta da condessa or beribá (Brazil) (Manica, 2000), anona babosa or zambo (Mexico), anón (Peru), chirimoya (Ecuador),

© Paull and Duarte 2012. Tropical Fruits, 2nd Edition, Volume II (R.E. Paull and O. Duarte)

1

2

Chapter 1

mulato (Colombia), cachiman cochon or cachiman montagne (Guadalupe), anón cimarrón (Puerto Rico), anonillo (Panama) and candongo (Dominican Republic).

Area of origin and distribution Soursop is the most tropical of and produces the largest fruit among the Annona species. The Caribbean is the area of origin, although soursop was distributed very early to the warm lowlands of eastern and western Africa and to south-east China. It is commonly found on subsistence farms in south-east Asia, and was established very early in the Pacific islands. Soursop is considered well suited to processing and for use in local markets for fresh consumption. It is grown extensively in Mexico, from Culiacan to Chiapas, and from Veracruz to the Yucatan Peninsula in the Gulf region. Large orchards are seen in this region, with a total of more than 6000 ha being grown. Venezuela has around 4000 ha, Brazil more than 2000 ha and Peru almost 500 ha. Colombia and Ecuador have also developed some modern orchards in the last few years for the local fruit markets and for industrial use. Exports of fresh fruit are very low. Rollinia originated in the forests of the Brazilian Amazon in the states of Acre, Rondônia and the Antilles. It has been spread throughout Brazil and other South American countries, as well as Florida (Manica, 2000; Donadio et al., 2002). This species, apparently cultivated since pre-Columbian times, is not widely cultivated for commercial purposes; rather, it occurs in backyard orchards or small plantings.

ECOLOGY Soil Soursop, as with most Annona species, is capable of growing in a wide range of soil types, from sandy soil to clay loams (Pinto et al., 2005). Nevertheless, higher yields occur on more well-drained sandy to sandy loam soils. Drainage is essential to avoid root rot. A. glabra is of interest as a rootstock because of its tolerance to flooded soils. Soursop can withstand some drought, but will experience flower abscission. The ideal soil pH is 5–6.5. Rollinia also prefers well-drained deep soils with a good content of organic matter but it can grow in poor acid soils high in exchangeable aluminum. The tree can withstand periodic flooding (Sousa, 2008).

Annonas: Soursop and Rollinia

3

Climate Rainfall Rainfall and high humidity during the peak flowering season greatly enhance fruit production by preventing desiccation of stigmas, prolonging their receptive period, and increasing fruit set and early fruit growth. Under very rainy conditions, as occurs in parts of Costa Rica, soursop has many leaf and fruit disease problems and is not normally grown commercially. In Colombia, soursop will grow successfully under rainfall conditions that can consist of two rainy seasons a year or just one. The alternating rainy and dry seasons have a positive effect on flower initiation. In addition, dry periods favor some leaf fall that results in new vegetative growth. Well-distributed yearly precipitation of 500–1500 mm results in adequate production, depending on its distribution. Yields are low when the rainfall is less than 500 mm (Duarte 1997; SCUC, 2006). Rollinia grows in hot, humid climates where a short dry period can occur, but in many cases monthly rainfall can be as high as 300 mm during the rainy season. It probably tolerates heavy rainfall areas better than the other fruitproducing species of this family. It needs at least 1500 mm of rainfall, and in many areas in the Amazon valley it will grow with more than 2700–3000 mm (Donadio et al., 2002). Temperature Temperature is a major limiting factor to production, with frost killing young trees while older trees show some tolerance. Soursop is the least tolerant of the Annona species (15–25°C mean minimum). Donadio et al., (2002) has reported that Rollinia can withstand mild frosts in the Jaboticabal area of Brazil, where the plant will defoliate in the winter. Soursop grows best under average temperatures of 25–28°C. It can be grown at elevations of up to 1000 m in the tropics and subtropics, as long as winter temperatures do not drop below 15°C. The temperature range for Rollinia is 1–2°C higher than for soursop, and it prefers the hot, humid tropics. Poor pollination, a frequent problem with all Annona species, occurs with high temperatures (30°C) and low humidity (30% relative humidity [RH]), even with hand pollination. Lower temperatures (25°C) and high humidity (80% RH) greatly improve pollination. Light and photoperiod Light penetration to the base of vigorous trees with a dense canopy in close spacing can be 2% of full sunlight, and there is very little fruit set. The soursop plant also tends to have a conic upright form. Pruning practices and spacing need to be adjusted to ensure light penetration. No photoperiod responses have been reported for any Annona species.

4

Chapter 1

Wind The soft wood of the trees makes them susceptible to wind damage and limb breakage. Wind may also be partially responsible for the penetration of collarrot organisms. Productivity can be improved by windbreaks and under-tree sprinkling to raise the RH above 60%.

GENERAL CHARACTERISTICS Tree The soursop is a small, evergreen tree that is slender and upright or lowbranching and bushy. It grows to heights of 4.5–9 m. Glossy, dark-green leaves are alternate, simple and entire, with an obovate to elliptic shape, and are 12.7–20 cm long (Fig. 1.1). The leaves emit a strong odour when crushed.

Fig. 1.1. The leaves and flower of soursop.

Annonas: Soursop and Rollinia

5

Rollinia generally reaches 6–10 m in height, but can grow as high as 20 m with a trunk diameter of 60 cm. The wood is soft, and the round or conic canopy is formed by branches that tend to grow vertically with laterals forming at their bases. The plant is semi-deciduous, with alternate oblong or elliptical oblong leaves, 12–20 cm long and 8–10 cm wide with an acuminated apices base. The leaves are leathery and the petioles are 6–12 mm long. Flowers occur once a year after leaf fall.

Flowers The flowers of Annona species are hermaphroditic and are produced singly or in small clusters on the current season’s growth, although flowers arising in ‘cushions’ from old wood are not uncommon. All lateral buds can have up to two vegetative buds and three flower buds. Soursop lateral buds are exposed in the leaf axil (Fig. 1.1), while the lateral buds of atemoya, cherimoya and sweetsop are normally ‘buried’ (subpetiolar). Adventitious buds can arise at any point on the trunk. New flowers continue to appear toward the apex of the shoot as flowers produced earlier at the basal portions mature. Soursop flowers are pale yellow and 2.5–4 cm long, with three thick, fleshy petals and three smaller inner petals alternating with the outer petals (Fig. 1.1). They have a peculiar odor. Defoliation of A. muricata manually or with ethephon spray promotes lateral branch growth and induces additional flower formation near the apex of the branches. Rollinia flowers are solitary or form small clusters on the current season’s growth (Moncur, 1988). They have three sepals and six petals. The external petals have the form of wings and give the flower the appearance of a propeller (Fig. 1.2A). They form a tubular structure at their junction in the center of the flower (Villachica et al., 1996). Annona species generally require 27–35 days for flower-bud initiation to anthesis. In A. squamosa, flowering can extend from 3–6 months or even longer, with heavy peaks. Two major flowering periods occur after periods of vegetative flushes, with the second peak coinciding with the onset of the monsoon season in India (Kumar et al., 1977). Flowering can occur year round with a continuous warm climate and water availability, while harvest becomes more seasonal in the subtropics.

Pollination and fruit set Natural pollination The flowers exhibit both dichogamy and a protogynous nature (Pinto et al., 2005). This poses a serious problem in obtaining high yields. A. muricata floral anthesis takes place mostly between noon and 8 pm and from 4 am to 8 am, with pollen release occurring between 4 am and 8 am (Moncur, 1988).

6

Chapter 1

Fig. 1.2. Rollinia flowers (A) and fruit (B).

Escobar and Sánchez (1992) have given a detailed description of the timing of the pollination process, dividing it into four phases that can take between 96 and 132 h. In phase I, the flower button opens slightly at the basal point of contact of the outer petals. Sexual structures are whitish and stigmatic liquid starts to become apparent and viscous, indicating the flower is receptive. In phase II, after 48–60 h the tips and bases of the outer petals have separated, the flower is more receptive since more stigmatic liquid is present, and the stamens become yellow, normally in the morning as the flower reaches its final size. In phase III, after another 24–48 h, the outer petals are semi-open and have a yellow-greenish color and more stigmatic liquid. The stamens have a dark-yellow color and the pollen is viable. Phase IV is reached 24 h later, when the outer petals are completely open and have acquired a sulfur color. Stigmatic liquid becomes less viscous and the flower is still receptive. The anthers are now cream in color and release viable pollen. The inner petals do not open, but are slightly separated in phases III and IV. After this all the petals, stamens and stigmata fall in 12–24 h, with the calyx, receptacle and peduncle remaining attached. Natural pollination in soursop is complex and in most cases results in very low fruit set and yields, with wind- and self-pollination being low (1.5%). The nitidulid beetles (Carpophilus and Uroporus spp.) are considered important pollinators of Annona flowers, although no significant effect has been observed from their presence in some cases. These beetles breed very fast in the remains of fruit, so it is recommended to maintain the rotting fruit attractant. Some reports have indicated that the presence of three nitidulid beetles per flower can increase fruit set by 25% (SCUC, 2006).

Annonas: Soursop and Rollinia

7

In the case of Rollinia, the flowers are also protogynous and the two female and male phases do not overlap to allow for self-pollination (Moncur, 1988). The petals open only slightly during the female stage. Insects are attracted by the scent, but nectar is not produced. Later on, the male-stage flowers open widely and insects forage for the pollen. All of this leads to poor fruit set. In Brazil, four species of leaf beetles (Chrysomelidae) pollinate the flowers with only 32% fruit set (Morton, 1987). Hand pollination Hand pollination is used to overcome poor pollination. Hand pollination is often very efficient, resulting in significant economic returns from the higher fruit set and larger and more symmetrical fruit. Hand pollination has also proven to be effective in Rollinia (Moncur, 1988). The pollen grains of flowers appearing early in a flowering season have thick walls and are high in starch, germinate poorly and give poor fruit set. The pollen of later flowers shows a high proportion of individual pollen grains without starch grains, and these germinate well. Pollen is obtained from opened flowers collected between 4 and 5 pm when the sacs have turned from white to cream. Flowers on thin branches or at the end of such branches should be harvested for pollen collection. Pollen can be obtained directly from picked flowers held in a paper bag or cardboard box, not a sealed container, at phase IV. Flowers picked at phase III will release pollen the next morning. Pollen from both stages can then be mixed for use. When the flowers are shaken over a shallow tray or in a plastic jar, the stamens and pollen separate and the pollen will stick to the jar walls. The pollen is then transferred to a small container. Pollen obtained in the afternoon can be held in a refrigerator for use the next morning. The moist pollen is applied to flowers in phase III or IV using a hair brush or even by rubbing the pollen on the stigma with an index finger. Some people remove one of the inner petals to make it easier to apply the pollen. Flowers can be tagged to keep control of the process. Pollination is performed between 6 and 10 am, and earlier if the days are hot and dry. Success in hand pollination is sometimes variable, being less successful on very humid overcast days and with young, vigorous trees. About 150 flowers can be pollinated by a skilled laborer in 1 h with a success rate of 80–100%. Flowers for hand pollination should preferably be taken from strong branches at the center of the canopy of trees older than 4 years. Growth regulators for fruit set Hand pollination in commercial orchards is tedious, time-consuming and costly. Attempts have been made to use growth regulators to regulate fruit set, with considerable variations in response. Auxin-induced fruit grow very slowly with less fruit drop, while gibberellic acid promotes fruit set and growth rate; however, it does not assist in post-set retention (Yang, 1988).

8

Chapter 1

Fruit The soursop fruit is a syncarp that varies from less than 0.4 kg to more than 4.5 kg, with some fruits reaching 12 kg. The size depends on genotype, extent of pollination and fertilization. A normal fruit is generally heart-shaped to oval (Fig. 1.3), but poor pollination results in unfertilized ovules that lead to small, distorted, irregular shapes. The skin is dark green with many recurved, soft spines. The flesh is juicy and white with a cottony texture, and contains many dark brown seeds that are about 2 cm long. The pulp has an agreeable sub-acid flavor with a distinct aroma. Soursop produces fruit throughout the year, but in most areas peak production is during summer and early autumn, sometimes with a secondary peak in the early spring. The Rollinia fruit is also a syncarp that generally weighs from 200 to 1000 g (Fig. 1.2B) and sometimes up to 4 kg. The flavor is like that of the soursop, but it is sweeter and less acidic; the aroma is also appreciated by consumers. The weight of 1000 seeds is about 315 g. The ripe fruit normally has a yellow skin and the pulp is cream or white, mucilaginous, soft and juicy. Fruit growth shows the typical sigmoidal curve, with maturation occurring in 16–24 weeks, depending on the species and growing conditions (Fig. 1.4). Low humidity (90 46–90 K2O (g/plant)

0–1

40

0

0

0

60

40

30

1–2

80

80

60

40

80

60

40

3–4

120

120

80

60

120

80

60

>4

180

120

80

40

180

120

60

Another recommendation suggests that non-irrigated bearing plants should be fertilized with 3 kg ammonium sulfate, 660 g triple superphosphate and 500 g potassium chloride (SCUC, 2006). This is applied in three equal portions during the year, preferably at the start, the middle and toward the end of the rainy season. The fertilizer should be lightly incorporated into the soils around the tree. Soursop also responds well to manure applications: either 15 kg per plant of decomposed cow manure or 3–4 kg of decomposed poultry manure. In cool subtropical areas, most vegetative growth takes place during the warmer months from spring to autumn. A reduction in nitrogen during the winter minimizes new vegetative growth in young trees that are vulnerable to cold temperatures. As with other perennial fruit trees, soil and plant tissue analyses are the techniques most used to evaluate the nutritional state of the plants. Soil sampling in adult soursop orchards should be similar to that recommended for other crops. For leaf sampling, the recommended method depends on the age of the plant, the position of the leaf in the canopy and on the branch and, as with many fruit crops, whether the branches are fruiting or not. Pinto and da Silva (1996) recommended collecting 8- to 9-month-old leaves that are free from fertilizer or agrichemical residues. The sample should consist of about 100 leaves for every 5–7 ha. Four leaves should be obtained from each of 25 randomly selected plants. The orchard should be divided into smaller plots according to soil characteristics. Samples should not be taken from sick or abnormal plants. Flowering time and periods of heavy rain should be avoided. Select plants of similar size and age, and avoid recently fertilized plants. Normal leaf concentrations for nitrogen and potassium in Brazil are 1.6- to 2.0-times greater than those from deficient leaves. Comparing data from Avilán (1975) and Silva and Silva (1997), there is a greater difference in Venezuela than in Brazil between normal and deficient leaves with regard to nitrogen, while the variation is less for potassium (Table 1.2).

Annonas: Soursop and Rollinia

15

Table 1.2. Leaf nutrient concentration for soursop in Venezuela and Brazil. Venezuela (Avilán, 1975)

Brazil (Silva et al., 1984)

Normal

17.6

25–28

Deficient

11.0

13–16

2.9

1.4

1.1

0.6–0.7

Normal

26.0

26.1

Deficient

12.6

26.4

Normal

17.6

10.8

Deficient

10.8

4.5

0.2

1.5–1.7

Element

Concentration

Nitrogen (g/kg) Phosphorus (g/kg)

Normal Deficient

Potassium (g/kg) Calcium (g/kg) Magnesium (g/kg)

Normal Deficient

Boron (mg/kg)

0.08

1.1–1.3

Normal

–

35–47

Deficient

–

6–14

Pest management Diseases A number of diseases of soursop have been reported (Table 1.3). Anthracnose, caused by Colletotrichum gloeosporioides, is the most serious disease on soursop, particularly in areas of high rainfall and humidity and during the wet season in dry areas. This disease causes twig dieback, defoliation and dropping of flowers and fruit. On mature fruit, the infection causes black lesions. Black canker (Phomopsis annonacearum) and diplodia rot (Botryodiplodia theobromae) occur mostly on neglected trees and cause similar symptoms of purplish to black lesions, resulting in mummified fruit. Marginal leaf scorch is also caused by P. annonacearum, while B. theobromae causes twig dieback. Diplodia rot has darker internal discoloration and causes deeper, more extensive corky rot in fruit. Cylindrocladium fruit and leaf spot is caused by a soil-borne fungus, C. colhounii. It can cause almost total loss of fruit during years of persistent heavy rains. Symptoms begin with small dark spots, primarily on the shoulders of the fruit, which spread along the sides, enlarge, become dry and crack. Infection is skin-deep, but the fruit become unmarketable. Control measures recommended are good orchard sanitation with heavy mulching and lower-branch pruning to prevent splashing of soil during heavy rainfall (Sanewski, 1991).

16

Chapter 1

Table 1.3. Major diseases of soursop. Common name

Organism

Parts affected, symptoms

Region or country

Anthracnose

Colletotrichum gloeosporioides (Glomerella)

Flowers, fruit, leaves, dieback, seedling damping off

Universal

Armillaria root rot Armillaria luteobubalina

Roots, base of trees, decline

Australia

Bacterial wilt

Pseudomonas solanacearum

Tree wilt

Australia

Black canker (diplodia rot)

Botryodiplodia theobromae

Universal

Black canker Purple blotch

Phomopsis annonacearum Phytophthora palmivora

Leaf scorch, twig dieback, peel blackening, graft union rotting As for diplodia rot

Rust fungus

Australia

Phakopsora cherimoliae

Spots on immature fruit, fruit drop, twig dieback Leaves

Australia

Florida

Fruit rot

Gliocladium roseum

Fruit

India

Rhizopus rot

Rhizopus stolonifer

Fruit

Brazil

Seedling rot

Rhizoctonia solani Cylindrocladium spp.

Seedlings

Universal

Insects Insect pests of soursop occur in numerous growing areas (Table 1.4). One of the most serious insects in Mexico, Central America, Trinidad, Surinam, Colombia, Venezuela and Brazil is the Cerconota moth, which lays its eggs on young fruit. The emerging larvae tunnel into the pulp, causing blackened, necrotic areas. It is not uncommon to find every fruit larger than 7.5 cm infested. For this moth, the use of light traps is recommended, as well as picking and burying fallen fruit. The use of specific approved insecticides and the release of parasitoid have also proven effective (Escobar and Sánchez, 1992). The Bephrata or Bephratelloides wasp is also widely distributed throughout the Caribbean, Mexico, Central America and central and northern South

Annonas: Soursop and Rollinia

17

Table 1.4. Major insect pests of soursop. Common name

Organism

Parts affected

Country/region

Bephrata wasp (soursop wasp)

Bephrata meculicollis

Fruit

Wasp

Bephratelloides paraguayensis Cerconota anonella

Fruit

Thecla ortygnus

Flowers, young fruit Young fruit Stem, leaves Fruit Fruit Fruit Fruit Leaves Leaves, flowers Leaves, stem Leaves, stem

Mexico, Americas, Trinidad, Surinam Americas, Barbados Americas, Trinidad, Surinam Americas, Caribbean Queensland Universal Queensland Caribbean Caribbean, Mexico Australia Caribbean American tropics

Cerconota moth (soursop moth) Thecla moth Banana spotting Mealy bug Citrus mealy bug Southern stink bug Caribbean fruit fly Queensland fruit fly Potato leaf hopper Red spider mite Scale insects Coconut scale

Amblypelta lutescens Dysmicoccus spp. Planococcus citri Nezara viridula Anastrepha suspensa Bactrocera tryoni Empoasca fabae Several genera, species Saissetia coffeae Aspidiotus destructor, other genera and species

Fruit

Universal Caribbean

America. This wasp is considered to be the most important pest in Florida. Considerable damage to the soursop fruit has been observed in Mexico and Central America by the authors. The larvae infest the seeds and damage the pulp as they bore through the flesh to emerge when the fruit matures. Control measures include preventive spays with approved products during initial fruit growth. For both of these insects, very good control can be obtained by bagging the fruit using plastic bags either with holes or with the basal end open (Escobar and Sánchez, 1992; Broglio-Micheletti et al., 2001). The Thecla moth is widespread throughout parts of the Caribbean and in the American tropics, but it is not considered to be as serious a pest as the Cerconota moth and Bephrata wasp. Damage is primarily to the flowers. The larvae feed on flower parts, such as the perianth, stamen and stigmas, and the flowers fail to set fruit. Mature-green annonaceous fruit have been shown to be rarely infested by the Mediterranean fruit fly (Ceratitis capitata) and the Oriental fruit fly (Dacus dorsalis), but they are found occasionally in tree-ripened fruit. Bait sprays and field sanitation are recommended measures to minimize fruit-fly infestation. Fruit bagging also provides protection.

18

Chapter 1

Mealy bugs and various species of scale insects are found universally and usually become serious pests on neglected trees. The former is reported to be a major pest on marketable fruit in some areas of Australia (Sanewski, 1991). Red spider mites can become a serious problem in dry areas or during dry seasons. Heavy infestations have been observed on soursop flowers and leaves in the Tecomán area of Mexico during the prevailing dry period, with trees showing heavy flower drop.

Weed management Problem weeds, especially grasses and twining weeds, should be controlled before planting by cultivation and herbicides. Young trees should be protected from weed competition by hand weeding, mulching or contact herbicides. Shallow root systems limit the use of cultivation under the tree.

HARVESTING AND POSTHARVEST HANDLING Harvesting season, yield and harvesting The harvesting season is quite similar in most areas, especially for soursop and sweetsop, differing only in range (Table 1.5). A major problem in soursop cultivation is obtaining commercial yields and large fruit with a symmetrical shape. To increase fruit set and size and achieve a better shape, hand pollination has become an important aspect of cultivation practices in

Table 1.5. Peak harvesting seasons for soursop. Country/region

Month(s)

Caribbean

Year round

Brazil, center

May–September

Brazil, north-east

Year round

Florida

June–November

Hawaii

January–October

Indonesia

Year round

Mexico

June–September

The Philippines

June–August

Colombia

Year round

Puerto Rico

March–September

Annonas: Soursop and Rollinia

19

some areas. Rootstocks have been shown to greatly influence yield (Sanewski, 1991). In Hawaii, soursop yields from trees grown in a marginal field have shown approximately 43 kg/tree on 4-year-old trees, increasing to 83 kg/tree on 6-year-old trees. In Paramaribo, Surinam, soursop yields of 54 kg/tree at 278 trees/ha have been reported. Fruit is harvested when fully mature and firm. The skin-color changes as the fruit approaches maturity. The immature soursop fruit is dark green and shiny, losing its sheen and becoming slightly yellowish-green on reaching maturity. Determining harvest time by dating floral anthesis is impractical as flowering occurs over many months. If a rigid hand-pollination protocol is used, with removal of naturally pollinated fruit, days from anthesis can be used. Fruit is hand harvested and put into lug boxes or baskets. Harvesting is more difficult and time-consuming for soursop, because the trees are generally taller than those of other Annona species and the fruit are much larger. In large soursop orchards, mechanical harvesting aids are feasible and accelerate handling. Rollinia fruit turn yellow at maturity and should be harvested before they start to change color or as the process starts, but before they are completely ripe. Ripe fruit are soft and difficult to handle. The fruit should be harvested very carefully by cutting the peduncle with a sharp knife or pruning shears. Yields can vary from 25 to 60 fruit/tree/year for 5-year-old trees, while 15-yearold trees can produce 100–150 fruits/year (Vargas et al., 1999). Harvesting in Brazil is normally done between January and June, 4 months after flower anthesis.

Postharvest handling Harvested fruit should be handled with care to prevent bruising of the skin. This is especially important for fruit that are marketed for fresh consumption. Firm soursop fruit need to be held after harvest for 4–7 days at room temperature, with optimum quality processing occurring 5–6 days after softening begins (Paull, 1983). The skin of the ripening soursop fruit will gradually turn dark brown to black, but the flesh is unspoiled. Storage temperatures below 15°C cause chilling injuries and a failure to develop full flavor. Pre-cooling of fruit is essential to help extend the shelf life. Protuberances on the skin of fully ripe Rollinia are easily injured and they turn brown to almost black, making the fruit unattractive (Morton, 1987). When processed, soursop fruit are stored on racks in the shade and inspected daily. All fruit that yield to finger pressure are removed for processing. Slightly immature fruit will ripen but they lack the full flavor and aroma, and nectars prepared from the puree of such fruit have a flat taste. Pulp-recovery percentages have been reported to range from 62% to 85.5% (Paull, 1982).

20

Chapter 1

Differences in recovery percentages are caused by differences in equipment, extraction methods, cultivar and cultural practices, including environmental influences. The number of seeds per fruit also influences pulp recovery.

Compositional changes during fruit ripening All Annona species bear climacteric fruit. Soursop respiration begins to increase within a day of harvest and reaches its peak at days 6–8. Ethylene production is initiated approximately 48 h after initiation of the respiration rise, and reaches its peak at about the same time as the respiration peak reaches a plateau (Paull, 1983). Total soluble solids increase from around 10% to 16% during the 3 days of ripening. The major titratable acids are malic and citric acids. Days 6 and 7 are considered to be the optimum edible stage and coincide with the peak of ethylene production.

UTILIZATION Soursop fruit is marketed fresh to local markets. This fruit, of all the Annona species, has the best processing potential because of the excellent flavor characteristic of the pulp and high recovery from large fruit. Unfortunately, soursop has to be hand peeled and cored, an expensive and time-consuming operation. The fragility of the skin and the fruit’s irregular shape and softness limit machine processing. Soursop pulp is viscous and requires dilution to produce a desirable nectar viscosity; however, this diluted product is flat and weak. To overcome this dilution effect, the pH needs to be adjusted to 3.7 by adding citric acid and sugar to 15% total soluble solids to create a desirable balance between acidity, sweetness and flavor. Unsweetened and sweetened soursop pulp processed below 93°C show no changes in organoleptic properties. Freeze preservation produces a higher-quality product. Enriched pulp, sweetened or unsweetened, can be processed and stored frozen for re-manufacture as various products or reconstituted directly by the consumer. Puree can be used to prepare an iced soursop drink or mixed with other juices, or it can be made into sherbets and gelatin dishes. Soursop is a good source of potassium, riboflavin and niacin (Table 1.6). Rollinia pulp is normally eaten fresh, though in some parts of Brazil it is used to make a fermented wine. Sugar can be added to the pulp to make some desserts. The seeds have insecticidal properties (Vargas et al., 1999).

Annonas: Soursop and Rollinia

21

Table 1.6. Composition of 100 g edible portion of soursop (Wenkam, 1990) and Rollinia (Collazos et al., 1975, cited by Villachica et al., 1996). Constituent Proximate Water (g) Energy Protein (g) Fat (g) Carbohydrate (g) Fiber (g) Ash (g) Minerals Calcium (mg) Iron (mg) Magnesium (mg) Phosphorus (mg) Potassium (mg) Sodium (mg) Vitamins Ascorbic acid (mg) Thiamine (mg) Riboflavin (mg) Niacin (mg) Vitamin A Seed/skin (%)

Soursop

Rollinia

80.10 247 kJ 0.69 0.39 18.23 0.95 0.58

85.0 53.0 cal 1.1 0.4 12.9 1.2 0.6

9.00 0.82 22.00 29.00 320.00 22.00

– – – – – –

16.40 0.07 0.12 1.52 0 34

3.40 0.07 0.23 0.79 0 –

FURTHER READING Bayogan, E.R. and Paull, R.E. (2008) Soursop Annona muricata. In: Janick, J. and Paull, R.E. (eds) The Encyclopedia of Fruit and Nuts. CAB International, Wallingford, UK, pp. 42–46. Campbell, C.W. (1985) Cultivation of fruits of the Annonaceae in Florida. Proceedings of the Tropical Region of the American Society for Horticultural Science 29, 68–70. Coelho de Lima, M.A. and Alves, R.E. (2011) Soursop (Annona muricata L). In: Yahia, E.M. (ed) Postharvest Biology and Technology of Tropical and Subtropical Fruits. Volume 4: Mangosteen to White Sapote. Woodhead Publishing Ltd., Cambridge, pp. 363– 391. Love, L., Paull, R.E. (2011) Rollina. University of Hawaii at Manoa, College of Tropical Agriculture and Human Resources. Fruit and Nuts Publication F_N-21. Available from: http://www.ctahr.hawaii.edu/oc/freepubs/pdf/F_N-21.pdf. Accessed August 20, 2011.

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Marler, J.E., George, A.P., Nissen, R.J. and Andersen, P.J. (1994) Miscellaneous tropical fruits – annonas. In: Schaffer, B.C. and Andersen, P.C. (eds) Handbook of Environmental Physiology of Fruit Crops. Volume II: Subtropical and Tropical Crops. CRC Press, Boca Raton, Florida, pp. 200–206. Pinto, A.C. (2002) Soursop. In: Crisóstomo, L.A. and Nuamov, A. (managing eds) and Johnston, A.E. (ed) Fertilizing for High Yield and Quality Tropical Fruits of Brazil. International Potash Institute Bulletin, IPI, Horgen, Switzerland, pp. 202–217.

REFERENCES Alvarez-Garcia, L.A. (1949) Anthracnose of the Annonaceae in Puerto Rico. University of Puerto Rico, Journal of Agriculture 33, 27–43. Avilán, R.L. (1975) Efecto de la omisión de los macronutrientes en el desarrollo y composición química de la guanábana (Annona muricata L.) cultivada en soluciones nutritivas. Agronomía Tropical (Maracay) 25, 73–79. Broglio-Micheletti, S.M.F., Agra, A.G.S. de Melo., Barbosa, G.V.S. and Gomes, F.L. (2001) Controle de Cerconota anonella (Sepp.) (Lep.: Oecophoridae) e de Bephratelloides pomorum (Fab.) (Hym.: Eurytomidae) em frutos de graviola (Annona muricata L.). Revista Brasileira de Fruticultura 23, 722–725. Clement, C.R., Mueller, C.H. and Chavez Flores, W.B. (1982) Recursos genéticos de espécies frutiferas nativas da Amazonía Brasileira. Acta Amazonica 12, 677–685. Donadio, L.C., Moro, F.V. and Servidone, A.A. (2002) Frutas Brasileiras. Editora Novos Talentos, Jaboticabal, Sao Paulo, Brazil. Duarte, O. (1997) Guanábana. Boletín de Divulgación, Escuela Agrícola Panamericana, El Zamorano, Honduras. Escobar, W. and Sánchez, L.A. (1992) Guanábano. Manual de Asistencia Técnica No. 57. Sección Nacional de Frutícolas, Instituto Colombiano Agropecuario (ICA), Colombia. George, A.P., Nissen, R.J. and Brown, B.I. (1987) The Custard Apple. Queensland Agricultural Journal 113, 287–297. Hernández, M.C.L.V. and Nieto-Angel, D. (1997) Diagnostico Técnico y Comercial de la Guanábana en México. Memorias del Congreso Internacional de Anonáceas, Universidad Autonoma Chapingo (UAC), Chapingo, México. Kumar, R., Hoda, M.N. and Singh, D.K. (1977) Studies on the floral biology of custard apple (Annona squamosa Linn). Indian Journal of Horticulture 34, 252–256. Laprode, S.C. (1991) Variación estacional de nutrimentos foliares em guanabana (Annona muricata L.). Revista Corbana 15, 6–10. Manica, I. (2000) Frutas Nativas, Silvestres e Exoticas 1. Cinco Continentes Editora, Porto Alegre, Brasil. Mansour, K.M. (1997) Current status of Annonaceae in Egypt. Mesfin Newsletter 1, 5–10. Marler, J.E., George, A.P., Nissen, R.J. and Andersen, P.J. (1994) Miscellaneous tropical fruits – annonas. In: Scheaffer, B.C. and Andersen, P.C. (eds) Handbook of Environmental Physiology of Fruit Crops, Vol II. Subtropical and Tropical Crops. CRC Press, Boca Raton, Florida, pp. 200–206. Morton, J.F. (1987) Fruits of Warm Climates. Creative Resource Systems Inc., Winterville, North Carolina, pp. 88–90.

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Nakasone, H.Y. (1972) Production feasibility for soursop. Hawaii Farm Science 21, 10– 11. Paull, R.E. (1982) Postharvest variation in composition of soursop (Annona muricata L.) fruit in relation to respiration and ethylene production. Journal of the American Society for Horticultural Science 107, 582–585. Paull, R.E. (1983) Changes in organic acids, sugars, and headspace volatiles during fruit ripening of soursop (Annona muricata L.). Journal of the American Society for Horticultural Science 108, 931–934. Pinto, A.C. de Q. and da Silva, E.M. (1996) Graviola Para Exportação, Aspectos Técnicos da Produção. Embrapa-SPI, Brasília. Pinto, A.C. de Q., Cordeiro, M.C.R., de Andrade, S.R.M., Ferreira, F.R., Filgueiras, H.A. de C., Alves. R.E. and Kinpara, D.I. (2005) Annona species. International Centre for Underutilized Crops, University of Southampton, UK. Available from: http://www. icuc-iwmi.org/files/R7187_-_Annona%20monograph%202005.pdf. Accessed August 20, 2011. Samuel, R., Pineker, W., Balasubramaman, S. and Morawetz, W. (1991) Allozyme diversity and systematics in Annonaceae – a pilot project. Plant System Evolution 178, 125–134. Sanewski, G.M. (ed.) (1991) Custard Apples – Cultivation and Crop Protection. Information Series Q190031. Queensland Department of Primary Industries, Brisbane, Australia. SCUC (Southern Centre for Underutilized Crops) (2006) Annona: Annona cherimola, A. muricata, A. reticulata, A. senegalensis and A. squamosa. Field Manual for Extension Workers and Farmers. University of Southampton, Southampton, UK. Silva, A.Q. and Silva, H. (1997) Nutrição e Adubação de Anonáceas. In: São José, A.R., Souza, I.V.B., Morais, O.M. and Rebouças, T.N.H. (eds.) Anonáceas, Produção e Mercado. Universidade Estadual do Sudoeste da Bahia, Vitória da Conquista, Bahia, pp. 118–137. Silva, H.A., da Silva, A.Q., Cavalcante, A.T. and Malavolta, E. (1984) Composição mineral das folhas de algunas fruteiras do Nordeste. Anais do 7mo. Congresso Brasileiro de Fruticultura (Florianópolis), pp. 320–325. Sousa, N.R. (2008) Rollinia mucosa Biribá. In: Janick, J. and Paull, R.E. (eds) Encyclopedia of Fruit and Nuts. CAB International, Wallingford, UK, pp. 68–70. Thakur, D.R. and Singh, R.N. (1964) Studies on pollen morphology, pollination and fruit set in some annonas. Indian Journal of Horticulture 22, 10–17. Vargas, O., Alix, C., Lobo, A.D. (Authors), Duarte, O. and Sanchez, J. (Technical Reviewers). (1999) Frutales y Condimentarias del Trópico Húmedo. CURLA; PDBL; AFE/COHDEFOR; DICTA; SETCO; PROFORFITH, La Ceiba, Honduras. Villachica, H., de Carvalho, J.E.U., Muller, C.H., Diaz, C. and Almanza, M. (1996) Anona (Rollinia mucosa (Jacq.) Baillón), In: Frutales y Hortalizas Promisorias de la Amazonía. Tratado de Cooperación Amazónica, Secretaría Pro-Tempore, Lima, Peru, pp. 20– 24. Wenkam, N.S. (1990) Foods of Hawaii and the Pacific Basin. Fruits and Fruit Products, Raw, Processed, and Prepared. Vol. 4, Composition. Research Extension series 110. HITAHR, College of Tropical Agriculture and Human Resources, Honolulu, Hawaii. Worrell, D.B., Carrington, C.M.S. and Huber, D.J. (1994) Growth, maturation, and ripening of soursop (Annona muricata L.) fruit. Scientia Horticulturae 57, 7–15.

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Yang, C.S. (1988) Application of plant growth regulators on Annona culture. In: Lin, H.S., Chang, L.R. and Lin, J.H. (eds) The Application of Plant Growth Regulators on Horticultural Crops. Symposium Proceedings. Special Publication No. 12, Taichung District Agricultural Improvement Station, Changhua, Taiwan (Chinese, English summary), pp. 305–320.

2 BREADFRUIT, JACKFRUIT, CHEMPEDAK AND MARANG

The family Moraceae includes the fig and mulberry. The genus Artocarpus, which includes breadfruit, jackfruit, chempedak and marang, contains about 50 species with milky latex. Most species are native to Asia, and 15 produce edible starchy fruit that are frequently staples. The genus name comes from the Greek words ‘artos’ (bread) and ‘karpos’ (fruit). The three most important species are the more tropical breadfruit A. altilis (Parkinson) Fosberg (syn A. communis, Foster; A. incisus L.; Communis incisa), the jackfruit A. heterophyllus Lam. (syn A. integer [Thumb.] Merrill; A. integrifolius) and its close relative chempedak A. integrifolia L., (syn. A. polyphema Persoon; A. champeden [Lour.] Stokes). Other Artocarpus species are also grown: A. odoratissimus (marang), A. camansi (breadnut) Blanco, A. lakoocha Roxb. (monkey jack) and A. mariannensis Trécul. (dugdug). Species with edible fruit that are not commercially grown, but are collected and consumed in their native range, include A. anisophyllus Miq., A. chama Buch-Ham., A. fulvicortex Jarrett, A. hypargyreus Hance, A. kemando Miq., A. lanceifolius Roxb. subsp. lanceifolius and clementis Merr., A. nitidus Trécul., A. rigidus Blume, A. sarawakensis Jarrett., A. sericicarpus Jarrett, A. styracifolius Pierre, A. tonkinensis, A. Chevalier and A. vrieseanus Miq. (Love, 2008).

BREADFRUIT Introduction Breadfruit originates from New Guinea and possibly the Moluccas, with numerous varieties spread throughout the islands of the Pacific. It has been distributed throughout the humid tropics since the late 1700s. The tree was the reason behind Captain Bligh’s voyage to Tahiti and the mutiny on The Bounty (Spary and White, 2004). In many regions, the seeded and © Paull and Duarte 2012. Tropical Fruits, 2nd Edition, Volume II (R.E. Paull and O. Duarte)

25

26

Chapter 2

seedless cultivars have different common names. Seeded breadfruits are called breadnut (English), kelur or kelor (Indo-Malaya) and kamansi or pakok (Philippines), while seedless are sukun (Indo-Malaya) and rimas (Philippines). Other names include arbre à pain (French), sake (Thai and Vietnamese), árbol del pan or panapen (Spanish), fruta pao (Portuguese) and ulu, uru, kuru, uto, mei, lemae and mos (Pacific islands). Two closely related species that possibly contributed to breadfruit are breadnut A. camansi Blanco from New Guinea, the Indo-Malay region and possibly the Philippines; and dugdug A. mariannensis Trécul from western Micronesia. Breadnut is a wild ancestor of the breadfruit indigenous to the lowlands of New Guinea, where it grows in flooded riverbanks, secondary and primary growth forest, and freshwater swamps, and in cultivation. It may also be indigenous to the Moluccas and possibly the Philippines. Dugdug is morphologically very distinct from A. altilis and grows wild in Palau, Guam and the Northern Mariana Islands. Introgression between the two species has occurred in Micronesia and there are a number of hybrid varieties (Ragone, 1997). Breadfruit is principally grown as a subsistence crop in most areas of the world, with Pacific and Caribbean islands being the major production areas. Fruit range from 0.2 to 4.5 kg, depending on the cultivar. Yields vary from as low as 50–150 to as many as 700 fruit/tree, with an estimated yield of 16–50 t/ha based on a density of 100 trees/ha. Canopy volume is a good measure of the potential yield.

Ecology Soil A variety of soils with sufficient depth and good drainage are suitable. Soils with high levels of organic matter and fertility are recommended. On Pacific islands, breadfruit does grow on shallow coralline soils, demonstrating its considerable varietal adaptability. Climate Regular rainfalls of 1500–3000 mm/year and humidity of 70–90% are preferred. Rainfall is necessary for vegetative growth, flowering and fruit growth, with a bimodal pattern preferred with a 3–6 month dry season. The tree is sensitive to chilling, with no growth at temperatures of 5°C or lower. The tree is well suited to hot, humid, tropical lowlands, with temperatures of up to 38°C and altitude below 1500 m. Best production takes place below 650 m in the tropics. Full sun is required, and no photoperiodic events have been noted.

Breadfruit, Jackfruit, Chempedak and Marang

27

General characteristics Tree This fast-growing evergreen tree can grow up to 30 m in humid and wet areas, and can live for as long as 90 years. The tree is partially deciduous under drought or during the dry part of a monsoon climate. The alternate and ovate leaves, which are 20–75 cm in length, are dark green with none to as many as 13 lobes (Fig. 2.1A). The trunk is straight, with thick branches terminating in branches of 10–20 cm in length with two large deciduous stipules enclosing the terminal bud. Root suckers begin bearing in 3–5 years and seedling plants in 8–10 years.

A

B

C

D

Fig. 2.1. Breadfruit leaf (A), male (B) and female (C) flowers and immature fruit (D). Jackfruit and chempedak inflorescences are similar in shape. (From Nakasone and Paull, 1998, with permission from CAB International.)

28

Chapter 2

Flowers This monoecious species has the staminate (Fig. 2.1B) and pistillate inflorescence on a 4–15 cm peduncle in separate leaf axils. The drooping, spongy, club-shaped male (15–20 u 3–4 cm) inflorescence has minute flowers, each with a single stamen. The globose pistillate inflorescence (6–10 cm) is covered with numerous tiny flowers on a spongy axis. Each pistillate flower is reduced to a tubular calyx with a two-celled ovary, and a two-lobed stigma on a short style. Pollination and fruit set Rain encourages vegetative growth and flowering. Some cultivars can flower throughout the year under the right environmental conditions. Crosspollination is assured by the staminate inflorescences maturing before the pistillate. Following wind or insect pollination, fertilization occurs over 3–6 days in seeded cultivars. A high percentage (75%) of the florets are set, with the percentage being reduced in rainy weather. This reduction suggests that pollination is necessary to stimulate parthenocarpic growth. However, pollination is difficult as the rudimentary perianth acts as a physical barrier to pollination and argues against the fruit being parthenocarpic. Pollen sterility is also a factor contributing to reduced fertility and seed production. Paclobutrazol, naphthalene acetic acid and ethephon inhibit vegetative growth but fail to stimulate flowering. In the West Indies, methanol spray in the dry season has been found to enhance vegetative growth and bring about earlier and more profuse flowering. Solar radiation significantly influences the onset of flowering and female inflorescence production. Fruit set is also related to tree width, with fewer fruit setting on trees with a greater width; this is possibly associated with uneven light interception, and suggests that tree management including pruning and plant spacing can impact fruit yield. Fruit The fruit develops from the entire inflorescence as the perianths of the individual flowers attached to the central axis or core, fuse together and become fleshy (Fig. 2.1D). The fruit is normally round to oblong, sometimes cylindrical and 10–30 cm in length. The thin, reticulated skin is pale green or yellow–green when the fruit is mature, turning yellow-brown when ripe. The core is surrounded by a pale-yellow or creamy white edible pulp (Fig. 2.2). Most cultivars are seedless, but the seeded wild types have 10–150 brown seeds of 2.5 cm in length. Depending on the stage of maturity and cultivar, the core and the flesh will exude a white viscous latex that discolors greenish or reddish-brown on exposure to air. The skin also exudes latex and dried, hardened drops are an indication of fruit maturity in some varieties. The fruit matures in 13–21 weeks from the time the pistillate inflorescence is first detectable in the terminal leaf

Breadfruit, Jackfruit, Chempedak and Marang

29

Fig. 2.2. Mature breadfruit (front right), jackfruit leaf and bud (top right) and jackfruit (back).

sheath (Fig. 2.3). Optimum maturity occurs at 15–19 weeks and fruit at this stage are preferred, as it provides a 5-week period during which the fruit can be harvested and still be acceptable to the consumer.

Cultivar development Seedless cultivars are typically triploid (2n ≈ 84), with the reduced seed number in diploid (2n ≈ 56) cultivars probably due to accumulated mutations in clonally propagating plants using root suckers. Numerous varieties have been described (Table 2.1), although few have been compared at the same location. Triploidy is common in seedless types. Many Micronesian cultivars are hybrids or triploids of A. altilis, A. camansi and A. mariannensis, with some of the diploids being fertile. Molecular data support the conclusion that breadfruit is a complex of these three species. Seedy types are more common in the

Chapter 2

Total Sugars (g)

30

Fig. 2.3. Growth of breadfruit, showing the pattern of fruit diameter, fruit fresh weight, total sugars and fruit starch. (Redrawn from Worrell et al., 1998.) AIS, alcohol-insoluble solids. Table 2.1. Fruit characteristics of selected widely distributed breadfruit cultivars. (From Ragone, 2011 and others.) Variety

Origin

Shape

Flesh, seeds

Ma’afala

Polynesia

Small oval

Maopo

Polynesia

Puou

Polynesia

Oval to broad ovoid Round, oval or heart-shaped

White flesh, seedless, occasionally with one or two seeds Pale white or creamy, seedless Creamy paleyellow, seedless, occasionally with one or two seeds Light yellow–green, seedless Creamy-yellow, seedless

Meinpadahk Micronesia Oval to asymmetrical Yellow-heart Caribbean Oval

Fruit weight (average kg) 0.8

2.5 1.9

1.1 2.0

Breadfruit, Jackfruit, Chempedak and Marang

31

western South Pacific. Evaluation and selection trials are currently underway in an extensive germplasm collection of Pacific Island breadfruit cultivars at the National Tropical Botanical Garden in Hawaii. This organization maintains an extensive website describing many varieties, although no breeding work has been reported. Variability has been observed in growth form, leaf shape, fruit quality, time to bearing, seasonality, keeping quality of fruit and salt tolerance.

Cultural practices Propagation and nursery management Seeds have 90–95% viability as soon as they are removed from the fruit, but this is lost in 2 weeks. Breadfruit is typically clonally propagated traditionally from root shoots or cuttings, although losses can be high with root suckers. Roots of 1.5–6 cm in diameter are cut into sections from 12 to 30 cm long. These are placed in clean, washed sand or potting media and kept moist. The roots can be placed horizontally below the surface of the medium or diagonally with the upper few centimeters exposed. The percentage of rooting ranges from 80% to 85% and takes 2–5 months, if kept well watered. Some success has been achieved with air layering, budding and grafting. There is interest in grafting seedless cultivars to rootstock of atoll-adapted seeded and seedless types. The cultivar Ma’afala has been used as a rootstock in Samoa. Field preparation No special orchard preparation is reported. Transplanting and spacing Plants are set out at 7–15 m, depending on the variety and growing conditions. Shade is provided for the first year as the young tree’s growth resumes. Irrigation practices Continued vegetative growth requires irrigation, especially during periods of drought. Irrigation reduces fruit drop during the dry season. Pruning The tree may be pruned to improve its shape, although regular pruning is not normally carried out. Trees that have grown too tall to readily harvest are often topped or trimmed back to keep the tree at a more convenient height. Fruit-bearing branches may break during heavy fruiting periods and these need to be removed. Some growers suggest that pruning branches that have borne fruit stimulates new shoots and limits tree height.

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Chapter 2

Fertilization General requirements have not been determined. The application of 100–200 g ammonium sulfate per tree 1 month after planting and again at 6 months is recommended (Coronel, 1983). The amount should be gradually increased until the trees start to produce fruit; thereafter, 500–1000 g complete fertilizer may be applied to each tree twice a year. A full bearing tree may require at least 2 kg complete fertilizer per application. Mulching and the application of organic manure two to three times a year, sometimes mixed with fertilizer, are used to increase and maintain growth rate. Pest management ‘Pingelap’ causes dieback from the top branches, and tree death is caused by an unknown organism with no method of control. This was a major disease in Micronesia in the 1960s. Other diseases include dieback (Fusarium, Pythium and Rosellinia), leaf spot (Cercospora), leaf rust (Uredo artocarpi), root rot (Phellinus noxius), fruit rot (Phytophthora, Phyllosticta and Rhizopus) and stem end rot (Phomopsis, Dothiorella). Fruit rot tends to be more of a problem on rough- than smooth-skinned varieties. Control measures involve removing affected fruit from the tree and not allowing fruit to ripen on the tree or rot on the ground. Mealy bugs, scales and twig borers are the major pests, with no control usually practiced. The fruit is a fruit-fly host. Recently, mealybugs have become a major problem affecting breadfruit in Kiribati, while Phellinus is causing crown rot and dieback of trees in Samoa (Brooks, 2002). Weed management Mulching around the base of the trunk is practiced to control weeds, conserve moisture and provide nutrients. Orchard protection A windbreak is not usually necessary. However, branches may break in high winds during periods of heavy fruiting. Breadfruit trees are occasionally used as windbreaks and shade for other crops.

Harvesting and postharvest handling Mature-green fruit are harvested as a starch vegetable, while some people prefer to eat the ripe sweet fruit. Harvested green fruit produce copious latex, especially from the cut peduncle and injuries on the fruit. Maturity is indicated by larger size, a slight change in the skin color to yellowish-green, small drops of latex on the rind and firm flesh texture. In addition, the segments are more rounded and smoother than in less mature fruit. As the fruit starts to ripen, the skin changes to a yellowish-green and begins to soften. Latex needs to be

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33

allowed to drain from the fruit after harvest and before washing in water to avoid latex stain. Fruit that are physiologically mature, with green skin, firm flesh, uniform shape and free from decay, sun-scald, cracks, bruises and mechanical damage, are marketed. Fruit at different growth stages are harvested to meet different market needs. There are no US or international grade standards. The fruit is graded according to appearance, blemishes, maturity and size. Various fruit counts are used depending on fiberboard carton size (9–18 kg). Fruit are sold on a weight basis. Telescope two-piece fiberboard cartons or one-piece cartons with dividers to minimize fruit movement and rubbing are used. The fruit is cooled as soon as possible after harvest and stored at 12–14°C and 90–95% relative humidity for a maximum of about 20 days. Hydrocooling is not recommended as it leads to skin browning. Film wrapping and coatings delay the softening and skin discoloration of fruit stored at 13°C. Controlled atmosphere studies have indicated that at 12°C, the best storage atmosphere is 2–5% O2 and 5% CO2 for up to 3 weeks. Chilling injury symptoms begin to develop within 7 days at 10°C. Symptoms are a brown scald-like discoloration of the skin, failure to fully soften, poor flavor development, and an increase in decay.

Utilization Breadfruit is typically eaten while still mature, firm and starchy (Fig. 2.3). In some areas, round immature fruit are also eaten cooked. The sweet ripe fruit is eaten as a dessert and can be used to make pies, cakes and other sweets. The fruit can be roasted, boiled, dried, pickled, used in bread making or fermented, while slices can be fried or stored in brine. The edible flesh comprises 70% of the fruit, and is 60–85% water, 1.2–2.4% protein, 22–37% carbohydrate and 0.2–0.5% fat (Table 2.2). The carbohydrate in mature fruit is mainly starch. Alcohols are the major aroma compounds, with cis-3-hexenol3-hydroxy2-butanone, cyclohexanediol and 2-pentanone making up 62% of the detected volatiles. The cooked seeds are also eaten, and contain 47.7–66.2% water, with 13.3–19.9% protein, 26.6–76.2% carbohydrate and 2.5–29% fat. The leaves and fallen fruit are fed to animals. The collected latex is used medicinally and as a caulk, glue and chewing gum.

JACKFRUIT AND CHEMPEDAK Introduction The jackfruit A. heterophyllus Lam. (Moraceae) and its very close relative chempedak A. integer (Thunb.) Merr. originated in India and Malaysia.

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Table 2.2. Composition of 100 g edible portion of breadfruit, jackfruit, chempedak and marang (Dignan et al., 1994; Wenkam, 1990). Constituent Edible portion (%) Proximate Water (g) Energy (kcal) Protein (g) Fat (g) Carbohydrate (g) Fiber (g) Ash (g) Minerals Calcium (mg) Iron (mg) Phosphorus (mg) Potassium (mg) Sodium (mg) Vitamins Thiamine (mg) Riboflavin (mg) Niacin (mg) Vitamin A (IU) Vitamin C (mg)

Breadfruit

Jackfruit

Chempedak

Marang

70

28

22

24–33

62 561 1.3 0.18 37 1.45 1.2

83 301 1.6 0.2 25.4 5.6 2.2

67 490 2.5 0.4 25.8 3.4 1.2

21 0.26 48 551 13

37 1.7 26 292 48

40 1.1 5 246 25

0.12 0.06 1.54 41 20.5

– 0.06 0.4 66 7.9

– 0.15 0.5 48 17.7

65.7–84.2 265–510 kJ 0.8–1.5 0.2–0.3 32.4 0.6–0.77 0.5–0.8 17 2.1 35 – – – – – – –

Jackfruit is also known as jacquier (French), nangka (Javanese and Malay), langka (Philippines), khnaor (Cambodia), makmi, khanum, banum (Thailand) and mit (Vietnamese). The English name is most likely derived from the Portuguese jaca, taken from the Malaya tsjaka. Jackfruit has been spread to Sri Lanka, southern China and south-east Asia, and further to tropical Africa. It was probably introduced into the Philippines in the 12th century and domesticated soon thereafter. The writings of Pliny the Elder as early as 100 AD mention jackfruit as being essential to the traditions in its place of origin (Campbell and Ledesma, 2003). The tree is still highly regarded by subsistence farmers from India and through south-east Asia for its fruit, timber and medicinal uses. Chempedak, also known as bankong, baroh (Malaysian/Indonesia), sonekadat (Burmese), champada (Thai), cempedak, jack tree (English), kathal, kathar (Hindi), campedak, cempedak, comedak (Javanese), chakka, pilual (Tamil) and mit to nu (Vietnamese) is distributed in Burma, peninsular Thailand and Malaysia, the Indonesian islands and western New Guinea. Chempedak is separated from jackfruit by having a smaller size with a slender peduncle, a male inflorescence that is pale green to yellow and not dark green, smaller and roundish fruit with a thinner rind, and more juicy flesh that is a darker yellow

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35

when ripe. In addition, the embryo radicle is immersed while in jackfruit it is superficial (Jarrett, 1959). Chempedak is restricted to south-east Asia, with some trees in Australia and Hawaii, while jackfruit is spread throughout the tropics.

Ecology Soil A variety of well-drained soils with a pH 5–7.5 can be used for jackfruit. Deep alluvial sandy and clay loams are preferred. The soils used for chempedak are normally uneroded and well-drained, although the tree tolerates temporary water-logging. Climate Cold, drought and flood tolerance limits the distribution of jackfruit to areas with more than 1500 mm rainfall evenly distributed throughout the year, without a prominent dry season. A warm and humid frost-free climate with minimum temperatures of 16–22°C and mean temperatures of 25–30°C, an altitude below 1000 m, and regions 25° north and south are desirable for good jackfruit bearing. It is grown in protected subtropical regions 30° north and south. Temperatures below 5°C severely damage trees and frost will kill developing shoots and fruit, and sometimes main branches. The trees do not do well in exposed locations with drying winds. They have some salt tolerance, but poor drought and flood tolerance. Chempedak is found at 0–1200 m in areas with a mean annual temperature of 13–47°C and mean annual rainfall of 1250–2500 mm. It is frequently an understory tree.

General characteristics Tree These monoecious, evergreen, latex-producing trees reach up to 25 m in height with a straight stem that branches near the base at an angle of 32–88°. All parts of the plant produce a milky-white gummy latex. The diameter of the normally dome-shaped dense canopy is 3.5–7 m in 5-year-old trees. The trunk is rarely buttressed with a girth of 30–80 cm and a grayish-brown, rough, uneven, somewhat scaly bark. Minute white hairs up to 0.5 mm long are found on the surface. The tree produces a long taproot. The glossy leaves are 4–25 u 2–12 cm (Fig. 2.2) and are usually hairy, with a dark-green top and pale-green underside. The leaves are arranged alternately on horizontal branches and spirally on ascending branches. Midrib and main veins are greenish-white to pale greenish-yellow. At the nodes, the stipules are

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fused around the stem that leaves an encircling scar after the leaf abscises. Chempedak has long wiry brown hairs (1.3 g) give the best seedling survival, as initial growth is slow. Seeds should be planted in freely draining growing medium under high humidity and shade. On germination (2–3 weeks), a radicle and plumule emerge from opposite ends; as soon as an adventitious root develops at the base of the young shoot, the radicle dies. Very slow seedling growth is a major problem and is attributed to poor seedling root development, having no root hairs and few laterals. A porous medium is best for seedling growth, with peat moss, bark and coarse sand being ideal. Growth increases significantly when side shoots emerge. The shoots generally emerge from every node. Grafting onto mangosteen seedlings is not difficult, although such plants are slower-growing and small-fruited with a shorter juvenile phase. Other rootstock have been tested with variable results. Positive results have been obtained with top-wedge grafting. Rooting of cuttings and air layers from mature trees have failed, although cuttings from seedling can be rooted under mist.

Field preparation No specific information is available regarding land preparation, although high rates of organic matter are recommended. Practices normally follow recommendations for other tree crops in the area. Deep-ripping is recommended for compacted soils.

Transplanting and spacing The long, delicate taproot and poor lateral root development mean that transplanting should be performed with care. Planting holes are prepared (1.2 u 1.3 m) in advance and organic matter added a month before transplant. Plants should have reached 60 cm before transplanting and a deep ball of earth set out, then watered heavily.

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Because of the need for shade and humidity, trees are often planted in mixed stands with durian, rambutan and coconut used as the dominant trees. An area of 40–80 m2 is allowed per mangosteen tree and trees 0.6 m high are planted at 8–10 m (110–140 trees/ha) or 11–12 m if a mechanical harvesting aid is to be used. Shade is maintained for 2–4 years, then gradually reduced to full sunlight.

Irrigation practices Mangosteen trees can withstand some water-logging but not drought, so a constant supply of water is required. A continuous dry period of 15–30 days should be imposed to limit apical bud growth (Fig. 6.2) and encourage flowering. The recommended crop coefficient at this stage is 0.00 (Table 6.2). This dry period is followed by two heavy waterings, spaced about 7 days apart. The trees should then be regularly watered during fruit growth and development at 80–85% of evapotranspiration (Table 6.2). Trickle irrigation or microsprinklers may be ideal for this crop.

Pruning The regular pyramidal crown and slow overall growth limits pruning. However, the tall nature of the tree (25 m) and fruit being borne singly make harvesting difficult; dwarf rootstocks and pruning may therefore be useful. Inside shoots and dead branches are removed along with suckers at the base of the main trunk. Water sprouts should also be removed. Severe pruning is never desirable. The limited pruning is carried out when there are no flowers, fruit or leaf flushes. Table 6.2. The crop coefficient (Kc) for mangosteen to estimate the daily water requirement (WR) for different stages of development, based on evapotranspiration (ET). WR = Kc u ET (Hiranpradit et al., 1998). Stage of development Vegetative growth Floral initiation Floral development Fruit setting Early fruit growth Late fruit growth Fruit maturity

Kc 0.60 0.00 0.75 0.75 0.80 0.85 0.85

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Fertilization Manure is recommended for young trees, along with mulching around the tree base. Non-bearing trees require a low, steady supply of nutrients, applied every 3 or 4 months. One recommendation is for 70 g nitrogen, 6 g phosphorus and 50 g potassium per tree per year until maturity. About 2–7 kg of complete fertilizer (10:10:19) per year is required for mature bearing trees. Half is applied when vegetative growth is being stimulated after fruit harvest (Fig. 6.2) and the remainder 2–5 weeks after anthesis. Dolomite can be applied at 0.2 kg per tree per year of age to 15 years, with a constant application rate for older trees. Manure is also used.

Pest management On the Malay Peninsula, Cankers on stems and young and older branches are caused by Zignoella garcineae P. Henn. The foliage on infested branches withers and eventually the whole tree dies. Trees should be cut and destroyed to arrest the spread. Thread blight, caused by Pellicularia koleroga Cooke, has been reported in Puerto Rico under conditions of excess shade and humidity. The smaller stems are first attacked, with the blight becoming severe when it attacks the leaves forming a whitish film over the blade. The leaves turn a clear brown, then darken before abscising. Removal of some shade and application of a Bordeaux mixture or other copper fungicides give control. Postharvest decay can be caused by Botryodiplodia theobromae. Only a few insect pests have been reported, possibly due to the bitter sap. Ants nesting in the tree can damage the growing tips. Mites can attack the fruit surface and make it unattractive for market. Caterpillar larvae and grass hoppers can cause some leaf damage. Fully ripe fruit are attacked by monkeys, rats and bats.

Weed management The slow growth of young trees means they can be quickly overtaken by weeds. Organic mulch is often used to assist with weed control and reduces evaporation from the soil around the trees. Mulch should not be placed against the tree trunk. Plastic mulch can also be used.

Orchard protection Shade is essential during the first 2–4 years. Shading (30–50%) can be achieved with mixed stands or crops such as pigeon peas, bananas, plantains,

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rambutan, durian and coconut, placed at least 1.5 m from the mangosteen tree. Cloth is also widely used to provide shade. Excessive shade (>50%) produces tall and skinny trees. Cover crops (e.g. Crotalaria, cowpeas, tropical kudzu) also help and have been recommended as long as the area around the tree is clear. Mangosteen trees must be protected from strong winds and salt spray.

HARVESTING AND POSTHARVEST HANDLING Harvesting The fruit are picked when soft and dark purple with the peduncle attached. Harvesting is by hand or with a pole and basket every 2–3 days. Mangosteen harvest indices have been based on the extent and intensity of purple pericarp development (Table 6.3). The stage at harvest depends on whether the fruit is intended for the local market or export; export fruit are picked at an earlier

Table 6.3. Mangosteen harvest index stages. Fruit are normally harvested between stages 1–4 and eaten from stages 4–7. The final total soluble solids figure was obtained after the fruit was allowed to ripen to stage 5 at 24°C (Tongdee, 1985) and fruit attachment force from the tree (Tongdee and Suwanagul, 1989).

Stage Pericarp color

Detachment force (kg) Latex

Seed/aril

0

Yellowish-white

2.2

Severe

1

Light greenishyellow with scattered pink spots Irregular pink– red Uniform pink background Red to reddishbrown Reddish-purple

2.09

Severe

1.19

Moderate Difficult

1.24

Slight

1.32

2 3 4 5 6

7

Dark purple, slight red coloration Dark purple– black

Not separable Not separable

Final eating flavor

Final total soluble solids

Inferior

15.2

Inferior

–

16

Moderate

Minimum stage Export

None

Readily

Export

17.7

1.32

None

Easy

18.3

1.32

None

Easy

Eating stage Eating

1.32

None

Easy

Eating

–

–

–

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stage. Fruit should not be harvested before the pericarp is a light greenishyellow with distinct irregular pink red spots over the entire fruit (stage 1). Fruit with less color development have excessive latex exudation at the peduncle and an inferior flavor when they do darken to the full purple stage in about 5 days. Care is essential to avoid mechanical injury, as a 20 cm fall causes significant damage to the aril. Fruit ripening on a tree takes place over 6–12 weeks. The amount of latex declines with maturity, while total soluble solids increase and acidity remains relatively constant after stage 1 (Fig. 6.5). Burst latex vessels on the fruit skin leave dried yellow latex (gamboge) that may be scraped off.

Postharvest handling

Acidity (% Citric)

Total Soluble Solids (%)

Fruit are graded to remove damaged fruit and for size and color. There are no US or international standards. Fruit are usually sold in single-layer fiberboard cartons of 2.25 kg with padding, sometimes in trays and individually wrapped to prevent injury (20–24 fruit/carton). In South-east Asia, the fruit are sold either in baskets or strung in long bundles of 10–25 fruit. The thick fruit wall hardens as the fruit ripens and during storage at low temperatures (22ºC Low Water, High N

Temperature >22ºC Low Water, High N

Temperature >22ºC High Water

Flowering

Floral Induction and Development

Temperature >22ºC Low Water, High N

Temperature >22ºC High Water

Temperature >22ºC Water Stress

Floral Induction and Development Prune Fertilize Irrigate

No Flowering

Temperature 22ºC High Water, High N

142

Temperature >22ºC High Water, High N

No Irrigation Induce Stress

First Flowers Remove Plastic and Irrigate

Fertilize

Fruit Set and Growth Irrigate

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Fig. 7.2. The fruiting cycle of rambutan, as affected by fertilization and water availability, under normal conditions (A) and when water stress is used to induce flowering (B). Soil surface covers and ditches are used to take away rainfall (C). The plastic cover is removed when tree flowering occurs (D).

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Fig. 7.3. Rambutan leaves (A), panicle (B), hermaphrodite flower (C), male flower (D) and fruit bunch (E) showing the spintern on the pericarp, and one fruit with half the pericarp removed to expose the aril that surrounds the seed.

and remain receptive for 1 day. Nectar production for both flower types begins at anthesis. Hermaphrodite trees with both functional male and female flowers are more desirable and are most commonly found in some rambutan cultivar selections, with male flowers in the range 0.5–0.9% (Lam and Kosiyachinda, 1987). Flower induction, pollination and fruit set Rambutan is not believed to have a cold requirement for flowering and is suited to tropical areas with a temperature range of 22–30°C. In Australia, flowering in the dry tropics (Darwin, 12.5°S) usually follows the onset of cool nights (18–12°C) in July to August (Diczbalis et al., 1996). In the wet tropics, however, flowering is reported to occur throughout the year regardless of the climate (Watson, 1988) but usually occurs from September to October following a short dry season. In Thailand, a drop in night temperatures of 2–3°C with the onset of the dry season has been suggested as the prompt for flowering. Multiple regression analysis showed that for every 1°C decrease in

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night temperature, flower induction increased by 6.7% (Manakasem, 1995). Temperatures lower than 22°C reduce leaf flushing and can extend fruit development to nearly 6 months. Management practices in Thailand are directed toward producing a large crop in the May to June period. Cultivars vary in their requirements for induction, leading to early- and late-season bearers. The cultivars ‘Jitlee’ and ‘R137’ are more suited to areas with some water stress than ‘R4’ or ‘R7.’ Foliar-applied paclobutrazol does not produce off-season flowering. Ringing and covering a narrow area of the bark (95% relative humidity) and low temperature (10–15°C). Fruit will brown rapidly once exposed to cool dry conditions such as experienced in supermarket displays, despite careful attention to harvesting and postharvest storage. Hence, exporters should strongly consider the use of retail-ready packaging such as bags or punnets (clam shells) in sizes that suit the intended markets.

Utilization World production figures are difficult to obtain, given that the major and smaller centers of production do not regularly update production data. Estimates based on data available from the mid 1990s suggest that total world production is in the vicinity of 1.2 million t (Vinning and Moody,

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1997). Recent production statistics suggest that the world area under rambutan exceeds 200,000 ha and production is approximately 1.5–2.0 million t/year (Campbell and Ledesma, 2003; Crane et al., 2003; Huang et al., 2003; Poerwanto, 2003; Salakpetch, 2003). Thailand, Indonesia and Malaysia account for approximately 80% of the total world production. The amount traded internationally is substantially less. UK fruit markets record receivables of fresh product from Honduras, Indonesia, Malaysia, Panama, the Philippines, Sri Lanka and Thailand. The trade of rambutan is somewhat limited by quarantine regulations, with a number of potential importing countries imposing strict disinfestation requirements. Central American producers such as Costa Rica, Guatemala, Honduras and Mexico supply local and mainland USA markets. Australia is capable of producing up to 1000 t of rambutan in favorable years, with approximately 100 t exported to Japan. Hawaii produces approximately 120 t, with most being consumed locally and some exported to the mainland USA and Canada after irradiation. Rambutan is primarily consumed as a fresh fruit, but is also frozen, juiced, canned and dried in limited quantities (Anon, 1979). The proximate fruit composition shows high levels of potassium and some vitamins (Table 7.3).

PULASAN Botany The pulasan or poolasan, N. mutabile Blume (Sapindaceae), is sometimes confused with its close relative rambutan, which it closely resembles. The common names include ngo-khonsan (Thailand), rambutan-kafri and kapalasan (Indonesia), meritam (Sabah, Sarawak), bulala (Tagalog) and rambutan-kafri and rambutan paroh (Malaysia). The Dutch name in Java is kapoelasan. The species is native to the region from Burma to the Malay Peninsula, and also occurs in India (Assam), Burma, Indonesia, Malaysia and the Philippines. Wild trees are infrequent in lowland forests around Perak, Malaya, but abundant in the Philippines at low elevations from Luzon to Mindanao. It is grown to a limited extent in northern Australia and Hawaii. Although the fruit is considered superior to rambutan, it is not as commonly seen in the market. The lack of proven varieties, suitable production and postharvest handling practices, and consumer awareness of pulasan’s qualities contribute to its limited production.

Ecology Pulasan is a lowland primary forest tree. It grows well at below 350 m in the tropics, with annual rainfall of 1500–3000 mm. Well-drained rich soil that

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Table 7.3. Composition of 100 g edible portion of rambutan and pulasan (Nga, 1980; Ortiz and Cordero, 1984; Wills et al., 1986; Morton, 1987; Wenkam, 1990). Constituent Edible portion (%) Proximate Water (g) Energy (kJ) Protein (g) Lipid (g) Carbohydrate (g) Fiber (g) Ash (g) Minerals Calcium (mg) Iron (mg) Magnesium (mg) Phosphorus (mg) Potassium (mg) Sodium (mg) Vitamins Ascorbic acid (mg) Thiamine (mg) Riboflavin (mg) Niacin (mg) Vitamin A (IU)

Rambutan 43 83 297 0.8 0.45 14.5 4 0.3 25 3 10 13 140 20 48 Trace 0.065 0.8 0

Pulasan 35–45 84–91 – 0.82 0.55 12.9 0.14 0.43 0.01–0.05 0.002 – – – – – – – – –

is high in organic matter is preferred, and the tree does not do well on sandy soil. Flowering is more common following a longer dry season than required for rambutan. In many ways pulasan is similar to rambutan in its climatic requirements, although it is less tolerant of high light during establishment. It is often found on riverbanks, but rarely in swamps.

General characteristics Tree Pulasan trees grow to 10–15 m in height. The alternate leaves are pinnate or odd-pinnate and 17–45 cm long. There are two to five pairs of opposite or nearly opposite leaflets, which are oblong- or elliptic-lanceolate, 6.25–17.5 cm long, and up to 5 cm wide (Fig. 7.5). The leaves are slightly wavy, dark

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green and barely glossy on the upper surface; they are pale and somewhat bluish with a few short, silky hairs on the underside. Flowers The very small, greenish, petalless flowers have four to five hairy sepals and are borne singly or in clusters on the branches of the erect, axillary or terminal panicles. Male flowers possess five to eight well-developed stamens with dehiscent anthers that shed viable pollen (Fig. 7.5). The hermaphroditic female flowers possess five to eight stamens attached to the base of the ovary and do not extend beyond the stigma (Fig. 7.5). The anthers are indehiscent. The pistil consists of a bi-lobed ovary with a single style, topped with a bifurcated stigma. Reproduction Seedling trees can be grouped into male trees that produce only male flowers and do not produce fruit, and female trees that produce functionally female hermaphroditic flowers. Pollen germination tests indicate that the male flowers produce viable pollen. Some hermaphroditic female trees may also produce functional male flowers since lone ‘Seebabat’ trees have been reported to set fruit on their own. Trees flower during June and August, and fruit mature during October to December in Malaysia and April to May in

Fig. 7.5. Pulasan trees, flowers and fruit clusters are very similar to those of rambutan. Male inflorescence (A) and hermaphrodite flowers (B). The fruit clusters (C) are tighter than those of rambutan and the fruit have short, thick, stubby spines or tubercles on the pericarp rather than spinterns. (From Encyclopedia of Fruits and Nuts 2008, Plate 78, courtesy of Dr. Mike Nagao.)

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Thailand. Flowering can occur twice a year (February to March and August to October) in locations such as Hawaii. Mature fruit can be harvested in spring or fall, roughly coinciding with the rambutan flowering seasons. Fruit Fruit are borne in clusters (Fig. 7.5). Although two carpels are present on each flower at anthesis, only one usually develops while the other aborts but remains attached to the base of the developing fruit. The fruit is 4–6 cm wide and 4–7 cm long, with a dark red or occasionally yellow, thick, leathery skin when ripe, covered with short, thick, stubby spines or tubercles. Fruit weigh between 50–80 g, and the edible pulp is 25–30% of the total fruit weight. The aril is white, juicy and sweet with 16–25% total soluble solids; it is not always attached to the seed testa. The seed is ovoid, oblong or ellipsoid, light brown in color and somewhat flattened. It is 2–3.5 cm long and weighs 2.0–2.5 g. Underdeveloped seeds are occasionally found in some fruit, which will also have low flesh weights. The single-seeded fruit exhibit a simple sigmoid growth pattern and mature at about 15–18 weeks after anthesis in the warm tropics. This fruit maturation can be extended by up to 6 weeks in cooler locations. As fruit mature, heavy and inconsistent rainfall can cause the pericarps to crack and result in loss of production. The development of ‘flat fruit’ is often observed. These fruit, which are normal in length, fail to develop fully and have a flattened appearance. These fruit are seedless and do not possess a well-developed aril. Lack of pollination may be responsible for this abnormal fruit development.

Cultivar development Two forms of pulasan are reported from Java: ‘Seebabat’ and ‘Kapoolasan seebabat.’ The fruit are mostly dark red and the tubercles are crowded together. The flesh of ‘Seebabat’ is very sweet and juicy, and separates easily from the seed. In the other group, the fruit is light red and smaller, and the tubercles are not so closely set. The flesh adheres firmly to the seed.

Cultural practices Propagation Propagation by seed is not favored as the seedlings may be male or female. Seeds are sown fresh and germinate rapidly. Air layers are easy to propagate, but are thought to be generally very short-lived. Budding grafting is difficult and has a low success rate. Successful budding has been reported if done in the rainy season on rootstocks already set out in the field. Superior rootstocks have not been identified and bud grafting is done on seedling rootstocks.

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Planting distances of 8–10 m are recommended. Grafted trees begin to fruit in 3–5 years. Trees often receive little or no fertilizer or other cultural attention. Pruning and training Flowering occurs from axillary and terminal buds, and regular pruning after harvesting is necessary to maintain tree size. Trees are highly branched as for other sapindaceous fruits, and early pruning and training are necessary to develop a strong scaffold of branches that are not subject to breakage. An open-center system is often used. Nutrition and fertilization Information on the nutritional requirements for pulasan has not been developed. However, based on the similar phenology and growth pattern to rambutan, fertilizer practices used in rambutan production will probably apply to pulasan trees. In the Philippines, a 15:15:6 mix with magnesium is recommended for non-bearing trees and 12:12:12 for bearing trees. Diseases, pests and weeds Diseases and pests have not been widely reported. Powdery mildew can occur on the leaves and sooty mold on the fruit. Leaf rollers, fruit borers and weevils also cause damage, and mite infestations have been observed in rootstocks grown in the greenhouse.

Harvesting and postharvest handling The fruit bunch is harvested when most fruit are dark red or yellow in color. The fruit bunches are accumulated in baskets before sorting. Postharvest handling is similar to that for rambutan.

World production and utilization Yields of 5000–6000 fruit/tree are reported for mature trees. Records in the Philippines indicate mature trees can produce 180 kg of fruit. The fruit is consumed fresh and has a similar nutrient composition to that of rambutan (Table 7.3). The fruit can be frozen and dried or used in juices. The frozen and dried product can be used in ice cream, desserts and preserves. Boiled or roasted seeds are used to prepare a cocoa-like beverage. Hydrocyanic acid has been detected in the bark and leaves. The volatiles are mainly aliphatic hydrocarbons (70%), of which pentadecane (61%) and aliphatic alcohols (19%) are the most dominant. The dried seed kernels yield 74.9% of a solid white fat, which melts at 40–42ºC to a faintly perfumed oil that has a possible use in soap-making. The wood is light red and harder and heavier

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than that of rambutan. It is of excellent quality but is rarely available. The leaves and roots are employed in poultices. The root decoction is administered as a febrifuge and vermifuge. The roots are boiled with Gleichenia linearis Clarke, and the decoction is used for bathing fever patients.

FURTHER READING Diczbalis, Y.A. and Paull, R.E. (2008) Rambutan Nephelium lappacium L., Sapindaceae. In: Janick, J. and Paull, R.E. (eds) Encyclopedia of Fruit and Nuts. CAB International, Wallingford, UK, pp. 809–816. Lam, P.F. and Kosiyachinda, S. (eds) (1987) Rambutan: Fruit Development, Postharvest Physiology and Marketing in ASEAN. ASEAN Food Handling Bureau, Kuala Lumpur, Malaysia. Morton, J.F. (1987) Fruits of Warm Climates. Creative Resource Systems, Winterville, North Carolina. Available from: http://www.hort.purdue.edu/newcrop/morton/ rambutan.html. Accessed 2 March 2011. Nagao, M.A. and Paull, R.E. (2008) Pulasan Nephelium mutabile Bl. Sapindaceae. In: Janick, J. and Paull, R.E. (eds) Encyclopedia of Fruit and Nuts. CAB International, Wallingford, UK, pp. 816–817. Salakpetch, S. (2003) Rambutan production in Thailand. Acta Horticulturae 665, 67– 72. Tindall, H.D. (1994) Rambutan Cultivation. UN-FAO Plant Production and Protection Paper #121. Rome. Wall, M., Sivakumar, D. and Korsten, L. (2011) Rambutan (Nephelium lappaceum L.). In: Yahia, E. (ed.) Postharvest Biology and Technology of Tropical and Subtropical Fruits: Volume 4. Woodhead Publishing Limited, Cambridge, pp. 312–333. Watson, B.J. (1984) Rambutan (Nephelium lappaceum L.), pulasan (Nephelium mutabile Blume). In: Page, P.E. (Compiler). Tropical Tree Fruits for Australia. Queensland Department Primary Industry Information Series Q183018, Queensland, Australia, pp. 198–203.

REFERENCES Allen, B.M. (1967) Malayan Fruits. Donald Moore Press Ltd., Singapore. Anon. (1979) Cultivation of Neglected Tropical Fruits with Promise. Part 6. The Rambutan. US Department of Agriculture Science and Education Administration. Anon. (1999) Reference re package sizes reaching the UK. Aradhya, M.K., Zee, F.T. and Manshardt, R.M. (1996) Genetic diversity in nephelium as revealed by isozyme polymorphism. Journal of Horticultural Science 71, 847–857. Arenz, M. (2002/2003) Nephelium mutabile (pulasan). In: Janssens, M. and Pohlan, J. (eds) Tropical Crops. Agricultural Science and Resource Management in the Tropics and Subtropics ARTS. Fruit and Industry Crops, PTS 140, Bonn, Germany, pp. 61–70. Available from: http://www.tropen.uni-bonn.de/new_website/englische_seiten/ Study/SAPINDACEAE_PAPERS2.pdf. Accessed 6 March 2011. Astridge, D.P. (2003) Rambutan IPM Development Phase 1. Insect Identification, Monitoring

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and Insecticide Evaluation. Rural Industries Research and Development Corporation, Kingston, Australia, project number DAQ-274A. Campbell, R.J. and Ledesma, N. (2003) Tropical fruits with increasing export potential in tropical America. Acta Horticulturae 665, 87–92. Chapman, K.R. (1984) Sapindaceae. In: Page, P.E. (compiler). Tropical Tree Fruits for Australia. Queensland Department Primary Industry Information Series Q183018, Queensland, Australia, pp. 179–191. Chin, H.F and Phoon, A.C.G. (1982) A scanning electron microscope study of flowers of carambola, durian and rambutan. Pertanika 5, 234–239. Clyde, M.M., Chew, P.C., Salma, I., Normah, M.N. and Rao, V.R. (2005) Genetic diversity of Nephelium ramboutan-ake Leenh. assessed using RAPD and ISSR markers. Acta Horticulturae 665, 171–181. Crane, J.H., Zee, F., Bender, G.S., Faber, B., Brunner, B. and Chia, C.L. (2003) Commercial sapindaceous fruit production in the USA. Acta Horticulturae 665, 93–101. Diczbalis, Y. (2002) Rambutan – Improving Yield and Quality. Rural Industries Research and Development Corporation, Kingston, Australia, publication number 02/136 Diczbalis, Y. (2004) Rambutan. In: Salvin, S., Bourke, M. and Byrne, T. (eds) The New Crop Industries Handbook. Rural Industries Research and Development Corporation, Kingston, Australia. Diczbalis, Y. and Alvero, G. (2005) Nutrition management of Australian longan and rambutan orchards. Acta Horticulturae 665, 301–310. Diczbalis, Y.A., Eamus, D. and Menzel, C.M. (1996) Environmental factors influencing growth and yield of rambutan, grown in the wet/dry tropics of northern Australia. Proceedings of the International Conference on Tropical Fruits, Kuala Lumpur, Malaysia, 23–26 July 1996, volume II, pp. 15–24. Hiranpradit, H., Chandraparnik, S. and Salakpeteh, S. (1999) Integrated Technology to Improve Durian Production, 2nd edn. Kasetsart University Press, Bangkok, Thailand. Huang, X., Huang, H.B., Gao, A. and Xiao, Z. (2003) Production of rambutan in China. Acta Horticulturae 665, 73–79. IBPGR (1986) Genetic resources of tropical and sub-tropical fruits and nuts (excluding Musa). IBPGR, Rome, pp. 123–125. Kawabata, A.M., Nagao, M.A., Aoki, D.F., Hara, K.Y. and Pena, L.K. (2005) Overview of rambutan phenology, flowering, and fruit set in Hawaii. In. Proceedings of the Fifteenth Annual International Tropical Fruit Conference, 21–23 October 2005, Hilo Hawaiian Hotel, Hilo, Hawaii, pp. 41–50. Available from: http://www. hawaiitropicalfruitgrowers.org/15th%20International%20Tropical%20 Fruit%20Conference%20Proceedings%202005.pdf. Accessed 25 February 2011. Kawabata, A.M., Nagao, M.A., Tsumura, T., Aoki, D.F., Hara, K.Y. and Pena, L.K. (2007) Phenology and fruit development of rambutan (Nephelium lappaceum L.) grown in Hawai’i. Journal of Hawaiian and Pacific Agriculture 14. Available from: http://www. uhh.hawaii.edu/academics/cafnrm/research/documents/Kawabata_000.pdf. Accessed 2 March 2011. Kozai, N., Keizer, M., dela Cruz, F., Sajise, P.E. and Idris, S. (2005) The marketing channel of two underutilized fruit species of Malaysia: pulasan (Nephelium ramboutan-ake (Labill.) Leech) and kuini (Mangifera odorata Griff.). Available from: http://www. underutilized-species.org/Documents/PUBLICATIONS/mktng_ch_2_und_spp. pdf. Accessed 9 March 2011. Lam, P.F. and Kosiyachinda, S. (eds) (1987) Rambutan: Fruit Development, Postharvest

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Physiology and Marketing in ASEAN. ASEAN Food Handling Bureau, Kuala Lumpur, Malaysia. Lambourne, J. (1937) The rambutan and its propagation. Malayan Agricultural Journal 25, 11–17. Landrigan, M., Morris, S.C. and McGlasson, B.W. (1996) Postharvest browning of rambutan is a consequence of water loss. Journal of the American Society for Horticultural Science 121, 730–734. Leenhputs, P.W. (1986) A taxonomic revision of Nephelium (Sapindaceae). Blumea 31, 373–436. Lim, A.L. (1984) The reproductive biology of rambutan, Nephelium lappaceum L. (Sapindaceae). Gardens Bulletin, Singapore 37, 181–192. Manakasem, Y. (1995) Changes in apices and effect of microclimate on floral initiation of rambutan (Nephelium lappaceum L.). Suranaree Journal of Science and Technology 2, 81–87. Menzel, C., Olesen, T., McConchie, C., Wiltshire, N., Diczbalis, Y. and Wicks, C. (2000) Lychee, Longan and Rambutan: Optimising Canopy Management. Rural Industries Research and Development Corporation, Kingston, Australia, publication number 00/29. Morton, J.F. (1987) Fruits of Warm Climates. Creative Resource Systems, Winterville, North Carolina. Available from: http://www.hort.purdue.edu/newcrop/morton/ pulasan.html. Accessed 2 March 2011. Nga, N.S. (1980) Rambutan Cultivation. Seminar buah-buahan bagi kakitangan cawangan Pengeluran Tanaman. Jabatan Pertanian Semenanjung. Malaysia, Kuala Lumpa, Malaysia, 24–26 June 1980. O’Hare, T.J. (1995) Postharvest physiology and storage of rambutan. Postharvest Biology and Technology 6, 189–199. Ortiz, A.J. and Cordero, O.L. (1984) Rambutan: composicion quimica del fruto y su conservacion. Turrialba 34, 243–246. Paull, R.E., Reyes, M.E.Q. and Reyes, M.U. (1995) Litchi and rambutan insect disinfestation: treatments to minimize induced pericarp browning. Postharvest Biology and Technology 6, 139–148. Poerwanto, R. (2003) Rambutan and longan production in Indonesia. Acta Horticulturae 665, 81–86. Poerwanto, R. (2009) Developing off-season production technique for rambutan. International Seminar on Recent Developments in the Production, Postharvest Management and Trade of Minor Tropical Fruits, 18–19 August 2009, Best Western Seri Pacific Hotel, Kuala Lumpur, Malaysia. Available from: http://www. itfnet.org/source/mainpage/newsAndEvent/contents/PDF_seminar2009/7.pdf. Accessed 2 March 2011. Poerwanto, R., Efendi, D., Widodo, W.D., Susanto, S. and Purwoko, B.S. (2008) Off-season production of tropical fruits. Acta Horticulturae 772, 127–133. Rossman, A.Y., Schoch, C.L., Farr, D.F., Nishijima, K., Keith, L. and Goenaga, R. (2010) Dolabra nepheliae on rambutan and lychee represents a novel lineage of phytopathogenic Eurotiomycetes. Mycoscience 51, 300–309. Salakpetch, S. (2003) Rambutan production in Thailand. Acta Horticulturae 665, 67–72. Salma, I. (1986) Rambutan (Nephelium lappaceum L.) Clones and Their Classification. Malaysian Agricultural Research and Development Institute, Kuala Lumpur, Malaysia, Report #107.

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Sarip, J., Hassan, S. and Idris, Z.A. (1996) The variations of F1 hybrids in rambutan (Nephelium lappaceum Linn.). In: Proceedings of the International Conference on Tropical Fruits, Kuala Lumpur, Malaysia, 23–26 July 1996, I, 161–164. Siebert, B. (1992) Nephelium L. In: Verheij, E.W.M. and Coronel, R.E. (eds). Plant Resources of South East Asia. No. 2. Edible Fruits and Nuts. Prosea, Bogor, Indonesia, pp. 233–235. Subhadrabandhu, S. (2001) Under-Utilized Tropical Fruits of Thailand. RAP Publication: 2001/26. FAO, Rome. Tankard, G. (1987) Exotic Tree Fruit for the Australian Home Garden. Recent Rare Fruit Discoveries in Malaysian Borneo. Thomas Nelson Australia, Melbourne, Victoria, Australia, pp. 117–125. Valmayor, R.V., Valmayor, H.L. and Gonzalez, L.G. (1961) Rambutan: Varieties and Culture. UP College of Agriculture Technical Bulletin 7, Laguna, Phillippines. Valmayor, R.V., Mendoza, D.B., Aycardo, H.B. and Palencia, C.O. (1971) Floral biology, flowering habitsand yield of rambutan. Philippine Agriculturist 54, 359–374. Van Welzen, P.C. and Verheij, E.W.M. (1991) Nephelium lappaceum L. In: Edible fruits and Nuts, Plant Resources of South-East Asia. Prosea Foundation, Bogor, Indonesia. Van Welzen, P.C., Lamb, A. and Wong, W.W.W. (1988) Edible Sapindaceae in Sabah. Nature Malaysiana 13, 10–25. Vinning, G. and Moody, T. (1997) A Market Compendium of Tropical Fruit. Rural Industries Research and Development Corporation, Kingston, Australia, publication number 97/74. Wanichkul, K. (1980) A study on fruit development, harvesting index and postharvest changes of rambutan (Nephelium lappaceum L.) var. Seechompo. MSc. thesis, Horticulture Kasetsart University, Thailand. Watson, B.J. (1988) Rambutan cultivars in north Queensland. Queensland Agricultural Journal Jan–Feb, 37–41. Wenkam, N.S. (1990) Foods of Hawaii and the Pacific Basin. Fruits and fruit products: Raw, Processed and Prepared. Volume 4. Composition. College of Tropical Agriculture and Human Resources, Research Extension, Series #110. Whitehead, D.C. (1959) The rambutan: a description of the characteristics and potential of the more important varieties. Malaysian Agricultural Journal 42, 53–75. Wills, R.B.H., Lim, J.S.K. and Greenfield, H. (1986) Composition of Australian foods. 31. Tropical and subtropical fruit. Food Technology Australia 38, 118–123. Wong, K.C., Wong, S.C., Loi, H.K. and Lim, C.L. (1996) Volatile constituents from the fruits of four edible Sapindaceae: rambutan (Nephelium lappaceum L.), pulasan (N. Ramboutan-ake (Labbill.) Leenh.), longan (Dimocarpus longan Lour.), and mata kucing (D. Longan ssp., malesianus Leenh.). Flavour and Fragrance Journal 11, 223– 229. Zalasky, H., Nawawi, A., Ting, W.P. and Tai, L.H. (1971) Dolabra nepheliae and its imperfect state associated with canker of Nephelium lappaceum and N. mutabile. Canadian Journal of Botany 49, 559–561.

8 PASSION FRUIT AND GIANT PASSION FRUIT

INTRODUCTION The passion flower family (Passifloraceae) includes about 18 genera with around 530 species of dicotyledonous, herbaceous or woody vines, usually with axillary tendrils. Erect shrubs and trees are rare in the family. The species are native to the tropical and subtropical regions of both hemispheres, growing at medium to high elevations where temperatures are moderate. Only two genera, Passiflora and Tetrapathaea, are cultivated. The most important genus is Passiflora, the species of which are mostly vines with axillary tendrils; the fruit is a many-seeded berry. The flowers of many species are conspicuous in their form and color and are grown for their ornamental value. Only 50–60 Passiflora species bear edible fruit, and most are unknown outside their area or origin or cultivation by the native people (Table 8.1). A number of species are considered commercial, and the fruit of P. quadrangularis, P. ligularis, P. laurifolia and P. mollissima are often found in village markets in Latin America. However, only the purple passion flower fruit (P. edulis Sims), the yellow passion flower fruit (P. edulis f. flavicarpa Deg.) and hybrids between the two are considered to be of value in international commerce (Table 8.2). This chapter discusses P. edulis, P. edulis f. flavicarpa and P. quadrangularis L. Commercially, the former two are referred to as ‘passion fruit’ (the name used in this chapter) and the latter as ‘giant passion fruit.’ The common names, besides purple or yellow passion fruit, include granadilla (English), grenadille and couzou (French), markisa and buah susu (Malaysia), linmangkon (Bangkok, Thailand), benchawan (Chiang Mai, Thailand), limangkan (Laos), maracuyá morado (purple) and maracuyá amarillo (yellow) (Spanish), gulupa (purple in Colombia), maracuya peroba (Portuguese), mara-cuia and maracuja (Brazil), fruta de pasion and pasionaria (Tagalog, Philippines), parcha and marflora (Ilokano, Philippines), parcha, parchita and parchita maracuyá (Venezuela), chinola (Puerto Rico), lilikoi and yellow lilikoi (Hawaii) and mountain sweet cup (Jamaica). © Paull and Duarte 2012. Tropical Fruits, 2nd Edition, Volume II (R.E. Paull and O. Duarte)

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Table 8.1. Selected Passiflora species, their areas of origin and use (Martin and Nakasone, 1970). Use Common name(s)

Species

Area(s) of origin

– Banana passion fruit

P. alata Dryand P. antioquiensis Karst P. banksii Benth P. caerulea P. coccinea Aubl.

– Blue passion flower Red granadilla Purple granadilla Wild passion flower, maypop, apricot vine Yellow granadilla, water lemon, Jamaica honeysuckle Sweet granadilla Sweet calabash, sweet cup, conch apple Banana passion fruit, curuba Giant granadilla –

Ornamental

Fruit

Brazil, Peru Colombia

X

X X

Australia Brazil to Argentina Venezuela to Bolivia Brazil Southern USA

X X X

X

X

X X

P. laurifolia L.

West Indies to Brazil and Peru

X

X

P. ligularis Juss. P. maliformis L.

Mexico to Bolivia West Indies to South America

X X

P. mollissima (HBK) Bailey P. quadrangularis L. P. vitifolia HBK

Venezuela to Bolivia Unknown

X

P. edulis Sims. P. incarnata L.

Nicaragua to Venezuela and Peru

X X

X

The giant passion fruit is also known in Spanish as granadilla gigante and granada (Central America), badea and corvejo (Colombia and parts of Venezuela), tumbo costeño (Peru), granadilla de fresco (El Salvador), granadilla real and sandía de passion (Bolivia), parcha granadina and parcha de Guinea (Venezuela), maracuja-assu, maracuya-acu, maracuja mamao and maracuja grande (Brazil), groote markoesa (Surinam), parola and kasaflora (Philippines), markiza, markesa and markesa (Indonesia), timun belanda, marquesa and mentimum (Malay) and barbadine (France, Vietnam).

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Table 8.2. Similarities and differences between Passiflora edulis Sims and P. edulis f. flavicarpa Deg. (Knight, 1980). Characteristic

P. edulis Sims

P. edulis f. flavicarpa

Ecology

Cooler elevation

Low elevation

Vine

Less vigorous

Vigorous

Leaves

Similar shape, smaller

Larger

Flowers

Fruit

Smaller, fragrant, less protandry, anthesis in the morning Purple, small

Larger, stronger fragrance, stronger protandry, anthesis in the afternoon Yellow, large

Juice

Mild acid

Acid

Chromosome number

2n = 18

2n = 18

Meiosis

Normal

Normal

Ovules, pollen grains

Fully viable

Fully viable

Compatibility

Self-compatible

Self-incompatible

Area of origin and distribution The well-known purple passion fruit is considered native to southern Brazil, and was widely distributed to other countries of South America and the Caribbean and into Asia, Africa, India and Australia during the 19th century. It is grown commercially mainly in Colombia, Ecuador, Kenya, South Africa, the Philippines, Australia and New Zealand. The fruit is sold locally and exported in its fresh form and as processed pulp. The origin of the yellow form, P. edulis f. flavicarpa, is unknown. It may have originated in Australia as a mutant form of P. edulis or seeds may have been obtained from tropical America. A hybrid origin of P. edulis f. flavicarpa is unlikely, as normal meiosis with fully viable ovules and pollen grains occurs. Both P. edulis and P. edulis f. flavicarpa have 2n = 18. An interspecific hybrid would exhibit some meiotic irregularities, leading to irregularities in fertility. The giant passion fruit is a native of tropical America, but the exact place of origin is unknown. It can be found from Mexico to Brazil and Peru, in the Caribbean, Malaysia, Vietnam, India, Sri Lanka, the Philippines and tropical Africa, and in the warmer parts of Australia, Hawaii and south Florida. There are no large plantations like those of yellow or purple passion fruit, and it is sold mainly in local markets.

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ECOLOGY Climatic preferences of the different species vary rather widely. The purple passion fruit is more adapted to the subtropics and higher elevations of the tropics with cool periods. The yellow passion fruit is grown commercially in more tropical areas or lowlands, with the main world producers being Brazil, Ecuador, Peru and Colombia. These countries are also the largest exporters of concentrated juice. In Brazil, P. edulis appears to be a variable species, with forms having different ecological preferences, including those represented by a yellow fruit type (Martin and Nakasone, 1970). The giant passion fruit is truly tropical, preferring high humidity and warm days and nights, although it will produce in the subtropics. It can also grow at up to 2000 m in the Andes in protected locations, and in other elevated areas of the world where there is no danger of frost.

Soil Passion fruit can tolerate a wide range of soil types, although the vines are highly susceptible to poor drainage and waterlogging. Soil pH may range from 5.5 to 6.8 and even higher. On the Peruvian coast, the yellow passion fruit has been shown to be fairly salt tolerant. The giant passion fruit prefers deep and fertile soils, with good drainage and rich in organic matter. The vine does well in alluvial and sandy soils, even if slightly alkaline. Too heavy soils are not recommended. The ideal pH is from 5.5 to 6.5.

Climate Rainfall A well-distributed annual rainfall is necessary for passion fruit production, especially if supplemental irrigation is not available (Duarte, 1997). However, rainfall must be minimal during the flowering period, as pollen wetted by free moisture bursts open and becomes non-functional. Furthermore, rain minimizes insect activity and hinders pollination. The yellow passion fruit has been grown quite successfully with rainfall of 800–1750 mm uniformly distributed throughout the year or with supplemental irrigation during dry periods. Yields of around 40 t/ha have been obtained with a total water supply of 1300–1470 mm. Moisture stress of less than –1.3 MPa leads to a significant decline in leaf area, flowering and yield (Staveley and Wolstenholme, 1990). Moisture stress may be one of the major environmental factors responsible for seasonal fluctuations in passion fruit yields (Menzel et al., 1986). When hybrid vines are

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subjected to water stress, leaf potential recovers within a day of irrigation, leaf growth returns to prestressed levels in about 4 days and net CO2 assimilation in 6 days (Menzel and Simpson, 1994). The flowers of the giant passion fruit open in the morning, so rains in the tropics are less likely to bother the pollination processes. It produces satisfactory yields with a well-distributed rainfall of 1500–2500 mm. Supplemental irrigation is needed with rainfall of less than 800–1000 mm. During the rainy season, the withered and dried flower parts get soggy and should be removed from the peduncle to avoid rotting of that end of the fruit. Temperature Different temperature regimes for growing passion fruit in the tropics can be based on altitude above sea level. The economic life of the purple passion fruit at about 800 m is 3–4 years, while plants between 1200 and 1500 m produce reasonable crops for about 8 years. Low temperatures (15°C day/10°C night) reduce vegetative growth and potential yield, while high temperatures (30/25°C) can prevent flower production (Menzel et al., 1987). Some hybrid cultivars show differences in the optimum temperatures for growth and yield. The cv. ‘Lacey’ does not flower at 25/20°C, while ‘K-23’ and ‘Purple Gold’ have reduced flowering (Menzel and Simpson, 1994). Purple passion fruit thrives and yields well at night temperatures of 4.5–13°C and day temperatures of 18–30°C. Mature vines of the purple passion fruit can withstand light frosts, but are injured at –1 to –2°C (Beal and Farlow, 1984). The yellow passion fruit is tropical in its requirements, exhibiting more vigor and a wider range of adaptability. The vine grows and flowers well from sea level to 600 m or even higher, depending on proximity to the equator. In areas with cool winters, flowering stops with the onset of the cold season and the plant will flower for only 6–9 months of the year. The giant passion fruit prefers a tropical climate, like that of the yellow passion fruit. It will do well on the dry coast of Peru where relative humidity is normally high. In more humid tropics, it does well as long as excessive rainfall does not occur during flowering. It can also grow in the subtropics, but its growth is significantly reduced during the cold months. The ideal average temperature is 24°C, without extremes in temperatures and no cold spells. Light Seasonal changes in solar radiation can significantly influence productivity. Lower average irradiance – in the cool season, during the wet season with cloudy weather and with self-shading – reduces plant growth, the number of floral buds and open flowers and vine growth (Fig. 8.1). Short periods (1 out of 4 weeks) of heavy shade significantly reduce foliar area, dry weight, flowerbud numbers, flowering and potential yield. Cultivars differ in response; cv. ‘Purple Gold’ is more precocious at lower light levels than ‘Lacey’ (Menzel and Simpson, 1988). There is an interaction of sunlight with temperature, as no

Length (cm) or Area (cm2 x 10)

Open Flowers or Buds per Vine

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Solar Radiation(MJ (MJ/m /Day) Solar Radiation m2–2 Day–1)

Fig. 8.1. The effect of solar irradiation on the hybrid ‘E-23’ passion fruit vine growth, leaf area, flower buds and number of open flower buds. (Redrawn from Menzel and Simpson, 1988.)

flowering occurs at high temperatures with low irradiance. A similar behavior has been observed for the giant passion fruit. Photoperiod Flowering of yellow passion fruit was suggested to be photoperiodic (Watson and Bowers, 1965). Artificially induced short days (8 h) prevent vines from flowering and no flowers are produced under natural day lengths of about 11 h or less in Hawaii (21°N). In the absence of light-interruption studies, these results can be interpreted as being due to greater solar radiation or higher temperatures (Menzel and Simpson, 1994). No data are available for the giant passion fruit, but it is assumed to be similar to the yellow passion fruit in this aspect.

GENERAL CHARACTERISTICS Vine As flowers develop on new vine growth, growth of the vine is essential for continued flowering. The vigorous perennial passion fruit vine has medium to large, toothed leaves (Fig. 8.2). The purple passion fruit has green tendrils, while the yellow passion fruit possesses reddish or purplish tendrils. The leaves of the yellow passion fruit are somewhat larger than those of the purple. The vine can grow to 10 m long (Ruggiero et al., 1996).

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Fig. 8.2. The stem, leaf, flower and fruit of Passiflora edulis f. flavicarpa.

The giant passion fruit has thick four-angled stems (hence its name) and these angles are winged. It also has axillary tendrils that can reach 30 cm, flanked by stipules. The leaves are alternate, oblong-ovate to broad-ovate, 8–15 cm wide and 10–20 cm long, round or cordate at the base, and abruptly pointed at the apex. The roots are superficial, with 60% in the upper 30 cm of soil (Borges and Lima, 2008).

Flowers The solitary large showy passion fruit flowers (7.5–10 cm in diameter) consist of five sepals and five white petals. These form a tubular calyx tube, usually surrounded by a thread-like crown or corona in the center (Fig. 8.2). The five stamens unite into an elongated stalk bearing the ovary, with three horizontal styles (0.5 cm in diameter). The ovary is superior, one-celled and with three parietal placentas. Flowers of the yellow passion fruit are larger and more

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fragrant than those of the purple passion fruit, with a strong tendency towards the protandrous habit (Table 8.2). Floral anthesis occurs about 40 days after the buds become visible in the yellow passion fruit. The giant passion fruit has even larger solitary fragrant flowers of about 12 cm wide, with five greenish or reddish-green sepals on the outside and pink, white or purple inside. The petals are white and pink. The corona filaments are 5–6 cm long and purple and white below, blue in the middle and pinkish-blue above around the pistil, style and stigma. The time from bud formation to floral anthesis in P. quadrangularis ranges from 17 to 24 days. The name ‘passion flower’ was given by early Spanish Jesuit missionaries, to whom the flower represented the passion of Christ and illustrated the crucifixion. The 10 sepals and petals represent the 10 apostles at the crucifixion; the fringed crown represents the crown of thorns; and the five stamens and three styles represent the wounds and nails, respectively. The tendrils are the cords or scourges, while the lobed leaves represent the hands of the persecutors. The white symbolizes purity and the blue the heavens. Flower buds are produced at every node of new growth. After four to 10 flowers have set fruit, further setting of the remaining flowers ceases, even when hand-pollinated. Fruit set resumes when the initially set fruit begin to mature. This leads to peaks of fruit production with continuous vine growth (Fig. 8.3).

350 l/Vine/Week N and K 35% Total

Jan

200 l/Vine/Week

350 l/Vine/Week

N and K 30% Total

N and K 35% Total

Feb Mar Apr May Jun

Jul

Aug Sep Oct Nov Dec

Month Fig. 8.3. The growth, flowering and yield of hybrid passion fruit vines in relation to pruning, irrigation and fertilization. (Redrawn from Menzel et al., 1989, 1993.) Mean of 2 years’ data from southern Queensland, Australia. K, potassium; Mg, magnesium; N, nitrogen; P, phosphorus.

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The alternation of fruit setting and cessation of setting, which leaves fruitless spaces on long vines, could be a physiological mechanism to balance the number of fruit to leaves and photosynthate supply.

Pollination and fruit set The flower is large with a strong fragrance, attractive colors, abundance of nectar and large sticky pollen, all of which is conducive to insect pollination. The pollination process and the self-incompatibility problem of yellow passion fruit and sometimes giant passion fruit are normally solved by insects, especially carpenter bees (Xylocopa). Other frequent visitors are honey-bees (Apis mellifera) and various flies. Carpenter bees are much more efficient pollinators because of the size of their bodies; their backs are more likely to make contact the anthers and stigma (Aubert, 1975). Fruit set is about 70% by natural pollination, while hand-pollination fruit set can reach 100%. Hand-pollinated fruit are larger, heavier and higher in juice content, because of the increase in seed number (Akamine and Girolami, 1959). In Honduras, hand pollination at 1 pm or 4 pm resulted in 53.5% and 58.6% fruit set compared with 44.6% for natural pollination. The handpollinated fruit were 20–25% heavier, and juice weight per fruit was 73.8% and 82.0% higher than for the natural-pollinated control. Seed numbers increased by 40%. Hand pollination at 4 pm gave better results, although not statistically greater than at 1 pm (Duarte and Sierra, 1997). Style curvature is crucial for passion fruit flower pollination and fruit set. When the flowers open, which is normally at noon, the styles are upright. They gradually recurve during the afternoon to approximately 55° in the first hour after anthesis and 85° by 6 pm, before reverting to an average of about 20° curvature at flower-closing time (Hardin, 1986). The most effective time for pollination is after the styles have completely recurved, with the stigmas being receptive only on the day of anthesis. Ruggiero et al. (1976, 1996) reported three kinds of flowers with respect to style curvature, sometimes on the same vine: total curvature (about 71% of flowers), partial curvature (20–23%) and upright styles (6–10%). Flowers with upright styles fail to set fruit with pollen from compatible vines and wither under natural conditions or when hand pollinated. Pollen of flowers with upright styles effect good fruit set when deposited on stigmas of total- and partial-curvature flowers of different vines, indicating high pollen viability. The purple passion fruit is self-compatible, as are its hybrids, with the yellow passion fruit often requiring cross-pollination. On pollination, stigmas must be kept dry for at least 2 h – the time necessary for pollen germination (Akamine and Girolami, 1959). Pollen bursts and becomes useless on contact with free water, although germinated pollen is not affected. Since flowers of the

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yellow passion fruit open during the afternoon, rain or irrigation by overhead sprinklers during the afternoon can greatly reduce fruit set. This is a problem in many tropical areas, where heavy afternoon rains result in low yields. The giant passion fruit is normally self-compatible but is sometimes protandrous. Certain lines can be self-sterile, needing the presence of other plants for cross-pollination. The flowers start to open at 5–6 am and take about 1 h to complete the process. At that time the styles are vertical; by 9 am they are completely curved and the anthers start releasing pollen. In the afternoon, petals and sepals close and the flower is flaccid. When hand pollination is practiced, the best time is between 9 am and noon when the styles are curved; pollination in the afternoon is less successful. An average fruit set of 8.8% was observed in one study (Duarte and Marín, 2002).

Fruit Fruit range from 6 to 8 cm in diameter by 7 cm in length in the yellow passion fruit with a weight of 70–130 g, although fruit weighing 200 g are not uncommon. EMBRAPA in Brazil has released selections with fruit weighing around 200 g. These have been introduced to Ecuador, Peru and Colombia. Fruit weighing as much as 650 g have been reported in Brazil (CampoVivo, 2010). This is achieved through selection, hybridization and good field management, especially nutrition and hand pollination. The purple fruit is normally 3.5–7 cm in diameter and 4–9 cm in height, with a weight of 60– 100 g (Ruggiero et al., 1996). Both passion fruit types are round to oval in shape and have a hard exocarp (Fig. 8.2). The mesocarp is a thin green layer beneath the exocarp and above the white endocarp, forming a shell of 3–6 mm. Each seed has a hard black testa and is surrounded by a juicy edible aril. The seeds are attached by peg-like funiculi to the endocarp. The yellow passion fruit has up to 350 seeds. The yellow to orange juicy aril pulp of the purple passion fruit is aromatic, with a very desirable flavor. Total soluble solids usually exceed 15% and total titratable acidity ranges from around 2.5% to 4.0% (Table 8.3), depending on the season. The yellow passion fruit pulp is more acid than the purple passion fruit (Seale and Sherman, 1960). The purple and yellow passion fruit take 60–90 days to mature (Fig. 8.4). Growth follows a sigmoid growth curve, reaching maximum size in about 21 days, when sclerification leads to a hardening of the shell. Subsequent fruit mass increase occurs at a slower rate and reaches a maximum at about 50 days from anthesis for purple passion fruit and 60 days for yellow passion fruit. The increase in sugars, with a concomitant decline in starch, occurs during this last phase. When maximum mass is achieved, titratable acidity begins to decline as maturity approaches. A positive correlation exists between the number of

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Table 8.3. Pulp characteristics of Passiflora edulis, P. edulis f. flavicarpa and some hybrids (Beal and Farlow, 1984).

Pulp (%)

Total soluble solids (%)

Titratable acidity (%)

Total volatile esters (ppm)

122

49

15.3

2.4

159

72

50

37

15.3

2.4

83

–

–

46

14.5

3.2

122

–

–

35–68

13.4–16.1

2.3–3.6

49–200

No. of seeds

P. edulis

36

P. edulis f. flavicarpa ‘3-1’ Other hybrids

Fruit Mass (g)

Acidity (% Citric) and Soluble Solids (%)

Fruit weight (g)

Time from Anthesis (Days) Fig. 8.4. Change in purple passion fruit mass, skin yellowing, total soluble solids and titratable acidity during growth and development. (Redrawn from Shiomi et al., 1996.)

seeds that develop and fresh fruit mass and juice content. Juice content reaches a maximum on the vine and declines due to dehydration after abscission. Growth of the giant passion fruit also follows a single sigmoid curve, reaching its final size 25 days after anthesis and ripening in 65–80 days (Duarte and Marín, 2002).

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CULTIVAR DEVELOPMENT Genetics and cytogenetics On the basis of established chromosome numbers of relatively few species, the 2n = 18 group is the largest, with all of the horticulturally important species and hybrids included (Storey, 1950). The horticultural species are hexaploids with fairly high interspecific compatibility and regular meiosis. Purple tendril color is dominant over green. Fruit-shell color is controlled by a single pair of genes lacking dominance, with three color types being recovered in the F2 (Nakasone et al., 1967). Inheritance data for crown rot indicate a simple dominant gene for resistance to Fusarium oxysporum f. passiflorae, with P. edulis f. flavicarpa being the resistant parent. The yellow passion fruit has also been found to be resistant to a similar disease in South Africa, attributed to Phytophthora nicotianae var. parasitica. The purple passion fruit is susceptible to passion fruit woodiness virus (PWV), while some yellow passion fruit lines are tolerant.

Breeding and selection In establishing a passion fruit breeding program, it is highly desirable to develop a collection of as many species as possible in at least two ecological zones (sea level and a higher elevation). The breeding objectives in Hawaii are: (i) oval-shaped fruit (10% more juice than in round fruit); (ii) flavor of purple passion fruit and acidity, fruit size, juice recovery and vine vigor of yellow passion fruit; (iii) bright tangerine-colored juice with high total soluble solids; (iv) high degree of self- and cross-compatibility and good fruit set; (v) resistance to wilting disease and Alternaria brown-spot disease; and (vi) resistance to broad mite and other insects. For other regions, breeding for cold tolerance and resistance to PWV, Fusarium and Phytophthora crown or collar rot and other problems must be added to the set of objectives (Farlow et al., 1984). Where the purple passion fruit is the primary crop, rootstock breeding for resistance to crown and root rots is a major objective. In Australia, lines produced from P. edulis u P. incarnata have shown improved cold hardiness and tolerance to the severe strain of PWV. The original F1 hybrid and selections from the F2 and F3 populations backcrossed to P. edulis hybrids and to P. edulis f. flavicarpa have shown promise as improved rootstock. In South Africa, P. caerulea is tolerant to both Fusarium oxysporum var. passiflorae and Phytophthora parasitica, and hence is used as a rootstock (Grech and Frean, 1986). Australia has developed purple hybrids (‘3-1,’ ‘E23,’ ‘Lacy’ and ‘Purple Gold’), which are maintained by grafting on seedlings of the yellow passion fruit. Breeding through interspecific hybridization has not been explored adequately in any sustained program. Numerous hybrids have been made and

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the most frequent cross is between P. edulis and its form P. edulis f. flavicarpa. This cross can be accomplished only if P. edulis is used as the female parent, as the reciprocal is strongly incompatible. The latter condition has discouraged the development of clonal cultivars in the yellow passion fruit. A cross between yellow passion fruit and P. alata produces fertile hybrids with high-quality fruit. Yellow passion fruit can be transformed using Agrobacterium tumefaciens, offering the possibility of incorporating genes for virus resistance and other desirable traits.

Cultivars Many growers plant selected seeds or use purple passion fruit vines grafted onto Fusarium-resistant lines of the yellow passion fruit. The higher acidity of the yellow passion fruit, along with the need to develop disease-resistant cultivars, has led to the development of hybrids (Table 8.3). The selection of hybrids between purple and yellow passion fruit has focused on winter and summer cropping and tolerance to passion fruit mosaic virus, nematodes, Alternaria spot and Fusarium wilt. In Australia, two or three hybrids are grown to spread production peaks, with ‘E-23’ and ‘Purple Gold’ being most widely used. The hybrids ‘Supersweet,’ ‘Land 3’ and ‘Misty’ are used in the subtropical parts of Australia, while the purple-skinned selection of the yellow passion fruit ‘Panama’ is grown in tropical areas. The most recent release in Hawaii was ‘Noel’s Special,’ a yellow passion fruit with an unusually bright orange-colored juice and tolerance to Alternaria brown spot. The round fruit averages 90 g in weight, yielding 43–56% juice by weight and with total soluble solids of 15–19.8%. Hybrids have been developed and released in Taiwan, with ‘Tainung No. 1’ being one of the most common. The yellow passion fruit ‘Hawaiana’ is used in Colombia and Venezuela, along with some of the modern Brazilian selections. There are a number of selections in Brazil, including ‘Muico,’ ‘Peroba’ and ‘Pintado’ (all purple) and the yellow ‘Miram’ and ‘Grande.’ More recently, Brazil has released selections (‘Sol do Cerrado,’ ‘Gigante Amarelo’ and ‘Ouro Vermelho’) from crosses of the yellow type with fruit that can weigh as much as 650 g (CampoVivo, 2010). The released hybrids are larger, with increased acidity and more orange aril. Giant passion fruit has no defined varieties, but there are some types or selections. Colombia has two types. One, from the province of Chocó, has a relatively small fruit of 10–15 cm long and 8–10 cm diameter, with sweeter arils and a thinner white pulp of about 1–1.5 cm and sparse foliage. The other is the giant or normal type, with fruit that are 25–30 cm long and 12–15 cm wide, and a white pulp of 2.5–4.0 cm thick that can amount to 60% of total fruit weight. The arils and juice are not as sweet as in the smaller variety.

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CULTURAL PRACTICES Propagation Passiflora species are readily propagated by seeds, cuttings, air layers or grafting on a selected seedling rootstock. Leafy yellow passion fruit cuttings can also be propagated easily with naphthalene acetic acid. High levels of naphthalene acetic acid cause a reduction in root number and vigor, although the rooting percentage is similar (Duarte and Franciosi, 1976). Grafting and budding are fairly easily performed. Cleft grafting is more successful with adult scions, while whip grafting works better with juvenile material. When the purple passion fruit or its hybrids are the desired cultivars, plants are propagated by grafting on seedlings of the yellow passion fruit. Grafted vines are more vigorous than their seedling counterparts and have longer lifespans. Grafting is done 50–55 cm above the ground to prevent soil contact with the scion. When yellow passion fruit is grown or used as a rootstock, plants are produced exclusively from seed. The yellow passion fruit has vigor and resistance to root and stem rots and nematodes. Each seedling has a different genetic make-up and cross-pollination can take place. Asexually propagated material shows selfincompatibility, and requires an orchard to be planted with vegetative material from a number of seedling plants that are randomly chosen. Seeds can be sown immediately or stored at about 10–13°C for future use. Seeds stored at room temperature for 3 months give better than 85% germination. Seeds germinate in about 2 weeks, although germination can extend over 2–3 months because of seed-coat dormancy. Cracking the seed coat increases germination, but scarifying with sandpaper or fermenting seeds with wall-degrading enzymes has no effect. However, seed cracking is feasible only for small quantities of seeds. Twelve-hour periods alternating between 20°C and 30°C also increases germination compared with a constant 30°C. Giant passion fruit seeds from 45-day-old fruit have about 23% germination, while seeds from 60-day-old fruit have 98–100% germination. The best treatment for optimum germination is to ferment the seeds in their juicy pulp for 2–3 days, followed by washing and superficial drying out for 3 days. Seeds at room temperature lose viability in 1 month (Duarte and Marín, 2002). Seeds put in seedbeds germinate in 2–3 weeks, and plants can be taken to the field when they are 20–30 cm tall. This plant can also be propagated fairly easy by semi-hardwood or mature wood cuttings of 30–40 cm long and 1–2 cm diameter, stuck directly in nursery bags (Alix and Duarte, 1999).

Transplanting and spacing Seedlings at the two- to four-leaf stage are transplanted into individual plastic containers, grown in semi-shade for 1–2 months and then gradually provided

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with more sunlight. Seeds can also be sown in 60 cell trays and taken directly to the field. Seedlings are considered ready for field transplanting when they have attained heights of 25–50 cm and have been hardened in full sunlight for 1–2 months. For grafted vines, the scion portion should have grown until about 25 cm and hardened. The practice of applying fertilizer in the planting holes varies widely, from no fertilizer to 1 kg of superphosphate in South Africa. In Hawaii and Australia, fertilizer (60–114 g of 10:5:20) and/ or manure is incorporated in a circular area (approximately 0.8 m diameter) around each planting site. The trellis is the principal initial cost of production. There are a number of different trellis types, each having variations in height, number of strands and placement of wires, length of cross-arms (if arms are used), spacing of posts and method of construction. The two most commonly used types are the I or ‘vertical’ or ‘fence’ trellis, with one to several wires strung parallel, one below the other, on upright posts and the ‘T’- or ‘cross’-type trellis, with three strands of wires, one running on top of the posts and the other two attached at the ends of each cross-arm. With taller posts, two to three strands of wires are used, spaced about 0.6–0.9 m apart. In the cross-type trellis, the cross-arm is 1.2–1.5 m long and is placed 0.4–0.6 m from the top of the post. For yellow passion fruit, some authors recommend the fence-type trellis when manual pollination is performed since the other trellis types make this activity more difficult. In Hawaii, the cross-type trellis was found to give higher yields over the ‘fence’type trellis. Trellis height is around 2.0 m. A higher trellis provides a longer time for vines to trail from the wires to the ground with less piling of vines at the top, due to better spreading of growth on the three strands of wires. The high trellis and spreading of vines by the crossarms allows greater exposure of the vine to sunlight. A ‘pergola’-type trellis can also be used but if the foliage gets too dense then some of the ripe fruit will stay on top and are lost, since harvesters cannot see or reach the fruit. Minimum row spacing for grape trellises should be about 3 m to permit mechanization. If the cross-type trellis with a 1.0 m bar is used, there should be a distance of 2 m between the ends of bars on the parallel trellis of the adjacent row. Plant spacing within the trellis row is dependent on the type of passion fruit being grown, with too high densities leading to lower yields (Fig. 8.5). In cooler subtropical areas, the purple passion fruit or its hybrids may be spaced 2.5–3 m apart because of less vigorous growth. In-row spacing may be up to 5 m if very vigorous growth occurs. For the yellow passion fruit in warm areas, plants can be initially spaced at 2.4–2.5 m; after the first harvest year, every other vine is thinned to provide a permanent spacing of 4.8–5.0 m (694 plants/ha). Taking advantage of the high yields in the first crop year may be well worth the added cost of the additional plants. Under poor soil and watering conditions, the initial spacing between plants can be much lower with better yields during not only the first but also the second year. The trellis systems used for giant passion fruit are very similar. Plants can

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Yield (t/ha)

176

Fig. 8.5. Vine spacing significantly affects the yield of yellow passion fruit during its third year at Viamao, Rio Grande do Sul, Brazil. (Redrawn from Manica et al., 1985.)

be transplanted once have reached about 25–30 cm for seedlings and 40–50 cm for plants from cuttings. With this species a ‘pergola’-type trellis with wires crossing at 50–60 cm can be used with posts in rows separated 3 m and 3–6 m between posts in the row, with more posts for a sturdier trellis. The fence-type of trellis is also used, with a height of 2.3–2.5 m and five lines of wire, separated by 45–50 cm (Martínez, 1981). If the plants have been set too close and the foliage starts to overcrowd then they can be thinned by eliminating every other plant in the row. The ‘T’ or ‘cross-type’ trellis can also be used.

Hand pollination Self-incompatibility in yellow passion fruit and some types of giant passion fruit is often solved by insects, especially the carpenter bee. If the work of the carpenter bees is not satisfactory or they are absent then hand pollination is performed. Pollination is conducted when the flowers are open, normally in the afternoon for yellow passion fruit and in the morning for the giant type. The finger of a gloved hand will trap pollen when touched to an open flower; this will transfer to the stigmas of the new flower and at the same time the glove will catch pollen from this new flower. This captured pollen is repeatedly transferred through the orchard. In the case of a fence trellis, the pollinator would go from a flower in one fence to a flower in the opposite-side fence, to make sure the flowers are from different plants and avoid incompatibility. An individual can pollinate 50–60 flowers per minute, and two or three people

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can cover 1 ha during an afternoon. Hand pollination should be performed whenever flowers are present, not only at flowering peaks, to ensure high yields from more and larger fruit (Ruggiero et al., 1996).

Pruning and training Planting holes are made 0.6–1.0 m away from the posts. In Hawaii, seedlings 45–60 cm tall are topped at the time of transplanting to force lateral shoots to develop, of which two to four leaders are allowed to grow. One or two of the lateral shoots are trained to grow in one direction on the trellis, with the remaining shoots growing in the other direction. Bamboo stakes with short branches and about the height of the wires provide excellent support for vines. Tendrils wrap around the bamboo branches, so tying the vines to the stakes is unnecessary. All other trailing branches are removed. If tying is used, care has to be taken to eliminate the ties before they strangle the stems. A single leader is preferred in some systems and is trained along the wire in one direction. In the fence system, a leader is allowed to grow until it reaches just above the first line of wire. At this point it is pinched and three shoots are allowed to grow: one will be directed to climb to the next line of wire, while the other two are directed along the wire in opposite directions. This is done for every line of wire. At the last wire, after pinching only two shots are left, which should go in opposite directions. Passion fruit vines produce flowers on the current season’s growth, and practices that encourage new lateral growth increase flowering (Fig. 8.3). Occasional pruning is needed, although the degree varies. Once a lateral has completed its fruiting it should be cut back to a developing side shoot as close to the main leader as possible. If no side shoot has formed then the lateral should be cut off at the fourth or sixth node from the main stem. Once the laterals reach the ground after 12–15 months, they should be cut back to 30 cm of the main leader. Pruning should be performed when fruit load is small (Joubert, 1984). If not pruned, laterals begin growing on the ground, the vines tend to form a tangled mass on the wires, and only the new outside growth bears fruit. Pruning of old growth can limit the current crop, while removal of new growth restricts future cropping. The following general conclusions are drawn: 1. Light, selective pruning, particularly at the end of the annual production cycle, enhances new growth and maintains high yields the following year. This consists of removing all vines about to reach the ground or growing on the ground. Vines are cut near the trellis wires, but a few nodes away from the main stems. Vines hanging only halfway to the ground are left. 2. Long vines should not be thrown over the trellis, as this only increases entanglement on the trellis and depresses yields.

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3. Some vine growth on top of the entangled tops of the trellis may be pruned, as fruit produced on these vines is apt to be lost in the maze of vines, especially when the planting is 2 or 3 years old. Pruned vines on the trellis should be left to dry in place, as attempts to remove the cut vines can damage uncut vines. 4. Cross-arm trellises of 2.4–3.0 m high, although more costly initially, offer some advantages, such as better spread of vines and greater height for vines to grow and reach the ground. It is also easier to remove old vines hanging down from the wires. Pruning is also recommended for the giant passion fruit. The formation pruning consists of eliminating all side shoots to leave a single stem, and is similar to that used for purple and yellow passion fruit. Production pruning consists of eliminating shoots that have already produced fruit in order to stimulate new shoots that will flower. At the same time, all damaged or diseased shoots should be removed (Martínez, 1981).

Irrigation

Node No., Open Flower No., Root Mass (g)

Adequate soil moisture is required to sustain vegetative growth and production (Fig. 8.3). No floral buds are initiated under dry conditions (Fig. 8.6) as vine extension and growth are curtailed. Production is generally associated with higher rainfall in the 2 months before flowering. In Australia, 300–400 l/vine/ week is required during the summer. Passion fruit are herbaceous and thus need a good supply of water to develop and produce properly.

Node No. Open Flower No.

10–3

10–2

10–1

100

Soil Water Potential (–MPa)

Fig. 8.6. Effect of different moisture stress applied for 10 weeks on the number of nodes produced, leaf area, open-flower number and root dry mass. (Redrawn from Menzel et al., 1986.)

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Fertilization

Flowers per Vine

Vine Extension (mm)

Recommendations for fertilization vary widely, with all directed at encouraging new growth throughout the season. Since all flowers occur on new growth, there is a high demand for nitrogen: leaf nitrogen levels above 4.5% are recommended (Fig. 8.7). Fruit mineral analysis indicates that to produce each 1000 kg of fruit/ha requires 33 kg/ha of fertilizer, based on a 10:5:20 formulation, assuming 100% uptake efficiency by the fruit; a more realistic uptake value is 50%. Based on 667 plants/ha (3 m u 5 m spacing), each plant should receive 4.4 kg of 10:5:20 fertilizer. In Brazil, Borges et al. (2002) prepared more specific formulations for amounts of nitrogen, phosphorus and potassium according to soil analysis and yields for irrigated yellow passion fruit (Table 8.4). Deficiency symptoms have been described for nitrogen, phosphorus and potassium and the microelements iron, boron, zinc, magnesium, calcium and sulfur (Abanto and Muller, 1976; 1977a,b). About 60% of passion fruit roots are in the upper 30 cm of soil, and almost 90% are between 0 and 45 cm from the base of the stem. In young orchards, fertilizers should be applied in a 20-cm-wide ring around and 10 cm from the trunk, gradually increasing this distance with the age of plants. In mature vines, fertilizer should be applied in a band 2 m long and 1 m wide, on both sides of the plants, and 20–30 cm from the trunk. The time of fertilizer application depends on the climatic conditions, general appearance and vine performance. In the first year in Hawaii about 113 g of 10:5:20 fertilizer is placed in the hole at planting, with the same amount

Leaf Nitrogen (%)

Fig. 8.7. Effect of leaf nitrogen on vine growth and flower production of ‘E-23’ passion fruit. (Redrawn from Menzel et al., 1989.)

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Table 8.4. Fertilization recommendation in the plantation, formation and production phases of irrigated yellow passion fruit (Borges et al., 2002). Phosphorous – resin (mg/dm3) 0–15 Nitrogen (kg/ha)

16–40

>40

Potassium – soil (cmolc/dm3) 0–0.07

0.08– 0.15

P2O5 (kg/ha)

At planting 150a 120 80 During growth (days after planting)

0.16– 0.30

0.31– 0.50

>0.50

K2O (kg/ha) 0

0

0

0

0

0

0

0

30

10

0

0

0

20

10

0

60

20

0

0

0

30

20

10

0

0

90

30

0

0

0

40

30

20

10

0

120–180

40

0

0

0

60

40

30

20

0 0

During fruit production (expected yield, t/ha) 35 a

As bovine manure.

applied every 6–8 weeks. In the second year, when vines become productive, application should be based on vine growth. In Malaysia, where temperatures allow year-round growth, 5.4 kg of a 10:5:10 fertilizer per plant per year in four applications is recommended for the yellow passion fruit. Similarly, four applications of 15:4:11 at 500 g per mature vine per application, alternating with four applications of urea at 460 g per vine per application, are recommended in Queensland for purple passion fruit and its hybrids (Menzel et al., 1993). No specific recommendations exist for the giant passion fruit, but it does better if planted in soils high in organic matter. A soil analysis should be performed, taking into account that this plant requires good amounts of nitrogen and phosphorus (Martínez, 1981). Yellow passion fruit dosages could initially serve as a reference.

Pest management Diseases Passion fruit has very few serious diseases, with the extent of disease depending on the species and the growing environment (Table 8.5). Alternaria brown-spot disease has been reported from various passion fruit regions of the

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Table 8.5. Diseases of passion fruit. Common name

Organism

Parts affected

Region

Anthracnose

Colletotrichum gloeosporioides

Leaves, fruit

Probably universal

Brown spot

Alternaria passiflorae, A. tenuis, A. tomato Alternaria alternata

Fruit, leaves

Universal

Fusarium oxysporum f. passiflorae

Roots, crown

Alternaria spot Fusarium wilt

Phytophthora blight Phytophthora nicotianae var. parasitica, P. cinnamomi Fruit scab Stem-end rot of giant passion fruit Woodiness virus (insect vectors) (a long, flexuous virus, 750 nm long)

Cladosporium herbarum Botryodiplodia theobromae

Australia Probably universal

Leaves, stem, fruit, Probably roots universal

Fruit

American tropics

Stem end

East Africa

Stem, leaves, fruit

American tropics, Australia, Malaysia, South Africa, Caribbean area

tropics and subtropics on both the purple and the yellow passion fruit. Fruit of the yellow passion fruit in high-rainfall areas can be 66–98% infected and most of the leaves defoliated. The reddish-brown to brown, sunken spots, 1.3–5 cm in diameter, are easily identified. When grown in low- to moderaterainfall areas, vines with high tolerance, combined with a good fungicidal spray program, can produce up to 80–90% marketable fruit. Fusarium wilt can cause devastating losses on the purple passion fruit, with a very rapid onset of 24–48 h. Symptoms include browning of the vascular system of roots, crown and stem. Phytophthora blight is serious where purple passion fruit is grown. It affects the vines, causing defoliation and rotting fruit. The disease may completely girdle the stem, and causes root rot in soils with poor drainage. In the giant passion fruit, rotting sometimes occurs at the proximal end where the dried flower parts remain attached and cover a concavity at the peduncle insertion. This holds rainwater, and if it does not quickly evaporate then rotting can occur. Therefore, elimination of the flower remains after fruit set is recommended.

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PWV is an almost universal, aphid-transmitted disease of both purple and yellow passion fruit. It is a serious problem in Australia, South Africa, Malaysia, Taiwan, Panama and the Dominican Republic. Infected plants have leaves with a light-green mosaic pattern and yellow speckling and crinkling. The fruit is misshapen, with a thick woody rind and shrunken cavities (McCarthy, 1982). PWV is caused by a long flexuous virus, 750 nm in length, belonging to the potyvirus group. It is transmitted by the aphid Myzus persicae, as well as mechanically by grafting or contaminated tools. There is no evidence of seed transmission. Insects The most troublesome pests are fruit flies (Table 8.6), as they are difficult to control even using a well-executed spray program. The flies can be particularly injurious to passion fruit grown at low elevations. Most fruit-fly damage occurs on young passion fruit, where the fruit will shrivel and drop. The larvae develop better in soft, immature fruit than in mature ones (Anon, 1972). Fruit-fly ovipositing can also cause crater-like scars on mature fruit. Aphids can attack young leaves and growing points, as do stinkbugs. Mealy bugs and several scale insects, including barnacle scale, can become a problem. Other pests, such as red-banded thrips (Selenothrips rubrocinctus), occasionally build up to serious proportions and cause defoliation. Mites are particularly prevalent in areas of low rainfall and during the dry season, damaging and defoliating vines; they are effectively controlled with sulfur sprays. The plants are also very susceptible to nematodes such as the root-knot eelworm (Meloidogyne sp.) and other species. In many cases, grafting on the more resistant yellow passion fruit is recommended (Villiers, 1982).

HARVESTING AND POSTHARVEST HANDLING Yield Passion fruit yields vary with climate, species of passion fruit, cultivation practices, trellis type, presence of disease and the abundance of appropriate pollinating agents. Among the two most commonly cultivated passion fruit, the yellow passion fruit has the highest yield potential, with 44.8 t/ha/year in Hawaii and 41.8–61.9 t/ha/year at the Malaysian Agricultural Research and Development Institute research station in Sungai Baging, Malaysia (Chai, 1979). In commercial orchards, a more realistic yield is between 20 and 30 t/ ha/year. The purple passion fruit is less vigorous. Yields of 5–10 t/ha/year can be obtained in Australia, with the hybrids having yields of up to 25 t/ha/year (Beal and Farlow, 1984). Average yields for the giant passion fruit are 15–20 t/ha/year in Colombia (Martínez, 1981). This can be increased with improved irrigation and fertilizer management.

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Table 8.6. Insect and mite pests of passion fruit. Common name

Organism

Mediterranean fruit Ceratitis capitata fly

Parts affected

Region

Mostly fruit

Hawaii, Central America, Panama, Mexico Hawaii, Panama, other areas Hawaii, Asia, parts of Africa, western Pacific, Malaysia Australia

Melon fly

Dacus cucurbitae

Oriental fruit fly

Dacus dorsalis

Mostly fruit, also vegetative parts Fruit

Queensland fruit fly Caribbean fruit fly

Dacus tryoni

Mostly fruit

Anastrepha sp.

Fruit

Leaf caterpillar Leaf caterpillar Leaf eater

Dione juno Agraulis vanillae Diabrotica speciosa Cryptorhynobus sp. Atta cephalotes Selenothrips rubrocinctus Brevipalpus papayanis Brevipalpus phoenicis Tetranychus cinnabarinus Hemitarsonemus latus Meloidogyne spp. Rotylenchus reniformis

Leaves Leaves Leaves

Borer Leaf-cutting ant Red-banded thrips Red spider mite Red and black flat mite Carmine mite Broadmite Nematodes

Caribbean, American tropics American tropics American tropics American tropics

Root, stem, branches Leaves Leaves

Panama

Vegetative parts

Universal

Bark, diebacks, fruit Mature leaves

Universal

Young terminal leaves Roots

Universal

American tropics Panama, Hawaii

Universal

Universal

Harvesting Hand-harvesting is the most costly operation in passion fruit culture and can account for approximately 40–50% of the variable costs. Normally, fruit are allowed to ripen on the vine and abscise. Fallen fruit are gathered once or twice per week, depending on the quantity. Fruit are gathered more frequently during rainy periods, and daily if sunburn is a problem in summer. Vineyard layout and management, such as locations of access roads, line lengths, row widths, trellis types, field grading, trellis orientation and pruning before

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vines trail on the ground, influence harvesting efficiency. Trellis posts aligned on the raised part of the bed, with ground sloping away on both sides of the posts, allows falling fruit to roll to the side, concentrating the fruit outside the canopy and making it easier to gather. Harvesting using hand-raking and a machine that straddles the fruit and sucks them up has been developed. Alternatively, fruit are picked up from a mown sward with minimal damage. Despite the fruit’s thick skin, it is very susceptible to mechanical damage. Mechanical harvesting aids cause damage and make the fruit generally suitable only for processing. The giant passion fruit should be harvested when violet skin appears at the distal end of the fruit and the peel becomes yellowish and translucent, starting at the apex. It will fail to ripen properly if harvested too early. The skin is susceptible to mechanical injury – even a slight pressure with the fingers will leave a mark. The fruit are cut from the vine using sharp knives or pruning shears and handled very carefully.

Postharvest handling Fruit for the fresh market are carefully handled in small, 5–10 kg fiberboard cartons. Marketing standards for the fresh-fruit market in Australia require half- to full-ripe fruit, not less than 35% pulp and larger than 4 cm in diameter. Diseased or badly blemished fruit are culled. Dark-purple fruit with 120–140 fruit/carton attract the best prices. Growers wax their fruit to extend shelf-life and secure higher prices. Purple passion fruit can be kept for up to 4–5 weeks with little weight loss at 5°C and 80–90% humidity (Fig. 8.8). The yellow passion fruit can only be stored for about 1 week at 5–7.5°C. Ethylene can be used to enhance the skin-color development of mature fruit without affecting soluble solids or juice pH. The giant passion fruit is a very susceptible to injury when ripe, so it is normally harvested during early ripening. The fruit can be transported in fiberboard boxes or wood crates in layers with some protective cushioning, although single-layer boxes are better. Alternatively, partially ripe fruit are packed in a vertical position with the proximal end at the bottom. It is preferable to wrap every fruit with paper or to cover it with a plastic foam net sleeve. It should be stored at 10°C and 85–90% RH for maximum life.

UTILIZATION Passion fruit is valued more for its unique flavor and aroma than for its nutritional value. According to Wenkam (1990), yellow and purple passion fruit are good sources of provitamin A, niacin, riboflavin and ascorbic acid (Table 8.7). Yellow passion fruit juice has 2410 mg/100 ml of vitamin A, while purple passion fruit has only 717 mg (Ruggiero et al., 1996). The

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Total Soluble Solids

Loss

Time in Storage (Days)

Fig. 8.8. Changes in mass and total soluble solids of purple passion fruit stored at 5°C, 10°C and 15°C. (Redrawn from Arjona et al., 1992.)

Table 8.7. Composition of 100 g edible portion of passion fruit (Wenkam, 1990) and giant passion fruit (Morton, 1987). Giant passion fruit Constituent Proximate Water (g) Energy (kJ) Protein (g) Fat (g) Carbohydrate Fiber (g) Minerals Calcium (mg) Iron (mg) Phosphorus (mg) Potassium (mg) Vitamins Ascorbic acid (mg) Thiamine (mg) Riboflavin (mg) Niacin (mg) Vitamin A (IU)

P. edulis

P. edulis f. flavicarpa

85.6 213 0.39 0.05 13.6 0.04

84.9 222 0.67 0.18 13.72 0.17

94.4 – 0.112 0.15 – 0.7

78.4 – 0.299 1.29 – 3.6

3.6 0.24 12.5 –

3.8 0.36 24.6 –

0.7 0.7 0.7 –

3.6 3.6 3.6 –

29.8 Trace 0.131 1.46 717

20.0 Trace 0.101 2.24 2410

14.3 – 0.033 0.378 0.004

– 0.003 0.120 15.3 0.019

Thick white flesh Aril and seed

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passion fruit’s characteristic juice flavor and aroma must be retained during processing. Pulp from Alternaria brown-spot-infected fruit can seriously affect juice flavor. Yellow passion fruit has an average juice yield of 30–33%, while purple passion fruit has a yield of 45–50%. The extracted juice is quickfrozen as a puree and kept frozen for later processing of finished products. The juice can be pasteurized (85°C, 1 min) prior to freezing. However, the flavor constituents of passion fruit are extremely sensitive to heat treatments and the pasteurization process can cause the loss of 35% of the volatile components. The strong, pleasing flavor of passion fruit permits its use as a pure juice or a constituent in various frozen and heat-processed punches. It adds an excellent flavor to other products, such as pies, cakes, sauces, salads and sherbets. The fresh juice and concentrates are refreshing mixers with alcoholic beverages, such as gin, vodka and rum. Other products include tropical fruit cocktail, passion fruit sherbet and ice, and jelly and jam combinations. The juice can be boiled down into a syrup that is used in the ice cream and pastry industries. Passion fruit processing produces large quantities of waste in the form of rind and seed, which creates a disposal problem. The waste is composed of 51% rind and 11% seed by mass for the yellow passion fruit. Dehydrated rind has been fed experimentally in rations to swine and dairy cattle, with good results. The seeds contain more than 20% oil; this is similar to that of soybean or safflower, and can be used for the same purpose. The oil has more than 80% unsaturated fatty acids. Giant passion fruit is normally consumed fresh. Its nutritional value and vitamin content are not as high as those of the yellow or purple passion fruits (Table 8.7). The white flesh of the ripe fruit, with the outer peel and the inner skin removed, can be cut into pieces and eaten like papaya. However, it does not have a very distinct flavor so is usually added to pieces of other fruits such as papaya, pineapple, melon, watermelon or banana and seasoned with orange, lime or lemon juice, or with its own juice and arils. The flesh pieces can also be sprinkled with sugar, orange liquor and orange juice, and eaten as a fruit salad. The arils can be eaten with the seeds. Young fruit can be cooked or steamed and eaten as a vegetable. The roots of old vines are eaten in Jamaica as a substitute for yams. The leaves, skin and immature seeds contain a cyanogenic glucoside and the pulp contains passiflorine. In excess passiflorine can cause somnolence, so in some places the flesh is used as a sedative to relieve asthma, diarrhea, headaches, neurasthenia and insomnia. The leaf and root decoctions are used as a vermifuge (Morton, 1987).

FURTHER READING Bora, P.S. and Narain, N. (1997) Passion fruit. In: Mitra, S.K. (ed.) Postharvest Physiology and Storage of Tropical and Subtropical Fruits. CAB International, Wallingford, UK, pp. 375–386.

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Martin, F.W. and Nakasone, H.Y. (1970) The edible species of Passiflora. Economic Botany 24, 333–343. Menzel, C.M. and Simpson, D.R. (1994) Passion fruit. In: Schaffer, B. and Anderson, P.C. (eds) Handbook of Environmental Physiology of Fruit Crops. Vol II. Subtropical and Tropical Crops. CRC Press, Boca Raton, Florida, pp. 225–241. Menzel, C.M., Winks, C.W. and Simpson, D.R. (1989) Passion fruit in Queensland. 3. Orchard management. Queensland Agricultural Journal 115, 155–164. Sao Jose, A.R., Ferreira, F.R. and Vaz, R.L. (1991) A Cultura do Maracujá no Brasil. Fundação de Etudos e Pesquisas em Agronomia, Medicina Veterinaria e Zootecnica (FUNEP). Jaboticabal, Brazil. Schotsmans, W.C. and Fischer, G. (2011) Passion fruit (Passiflora edulis Sim.). In: Yahia, E.M. (ed) Postharvest Biology and Technology of Tropical and Subtropical Fruits, Volume 4. Mangosteen to White Sapote. Woodhead Publishing Ltd, Cambridge, pp. 125–142. Winks, C.W., Menzel, C.M. and Simpson, D.R. (1988) Passion fruit in Queensland. 2. Botany and cultivars. Queensland Agricultural Journal 114, 217–224. Yockteng, R., d’Eeckenbrugge, G.C. and Souza-Chies, T.T. (2011) Passiflora. In: Kole, C. (ed.) Wild Crop Relatives: Genomic and Breeding Resources. Springer Berlin, Heidelberg, pp. 129–171.

REFERENCES Abanto, A.M. and Muller, L.E. (1976) Alterations produced in passion flower plants (Passiflora edulis Sims) by deficiencies of nitrogen, phosphorus and potassium, Turrialba 26, 331–336. Abanto, A.M. and Muller, L.E. (1977a) Alterations produced in passion flower plants (Passiflora edulis Sims) by deficiencies in manganese, iron, boron and zinc. Turrialba 27, 163–168. Abanto, A.M. and Muller, L.E. (1977b) Alterations produced in passion flower plants (Passiflora edulis Sims) by deficiencies of magnesium, calcium and sulfur. Turrialba 27, 221–225. Akamine, E.K. and Girolami, G. (1959) Pollination and Fruit Set in the Yellow Passion Fruit. Hawaii Agricultural Experiment Station Bulletin 39, University of Hawaii, Honolulu, Hawaii. Alix, C. and Duarte, O. (2000) Propagación de Especies Frutales Tropicales. CURLA; PDBL; AFE / COHDEFOR; DICTA; SETCO / PROFORFITH. La Ceiba, Honduras. Anon. (1972) Passion Fruit Culture in Hawaii. Cooperative Extension Service Circular 345 (revised), University of Hawaii, Honolulu, Hawaii. Anon. (1984) Passion fruit Culture, 7th edn. District Crop Survey, North Moreton Region, Queensland Department of Primary Industry, Brisbane, Australia. Arjona, H.E., Malta, E.B. and Garner, J.O. (1992) Temperature and storage time affect quality of yellow passion fruit. HortScience 27, 809–810. Aubert, B. (1975) Précocité de production de la grenadille violette Passiflora edulis Sims. a la Reunion. Perspectives de production. Fruits 30, 535–540. Beal, P.R. and Farlow, P.J. (1984) Passifloraceae. In: Tropical Tree Fruits for Australia. Information Series Q183018, Queensland Department of Primary Industry, Brisbane, Australia.

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Bester, C.W.J. (1980) Growing purple granadilla on yellow granadilla rootstocks. Deciduous Fruit Grower 30, 324–327. Borges, A.L. and Lima, A de A. (2008) Passion-fruit. In: Crisóstomo, L.A. and Nuamov (managing eds) and Johnston, A.E. (ed) Fertilizing for High Yield and Quality Tropical Fruits of Brazil. International Potash Institute Bulletin, IPI, Horgen, Switzerland, pp. 163–178. Borges, A.L., van Raij, B., Magalhães, A.F. de J., Bernardi, A.C. de C. and Lima, A. de (2002) Nutrição mineral, calagem e adubação do maracujazeiro irrigado. EmbrapaCNPMF. Circular Técnica 50, 1–8. Bowers, F.A.I. and Dedolph, R.R. (1959) A preliminary report on pruning of passion fruit. Hawaii Farm Science 7, 6–8. Campbell, C.W. and Knight, R.J. (1987) Production of granadilla. In: Cultivation and Production of Tropical Fruit: 13th NORCOFEL Congress. Tenerife, Canary Islands, pp. 225–231. CampoVivo Comunicações (2010) Híbridos da EMBRAPA e bom manejo levam a super maracujá. Available from: http://www.campovivo.com.br/noticias_online.asp?id_ noticia=9163. Accessed 10 July 2010. Chai, T.B. (1979) Passion Fruit Culture in Malaysia. Fruit Research Branch, MARDI, Sungai Baging, Malaysia. Chapman, K.R., George, A.P. and Cull, B.W. (1978) A mechanical harvester for passion fruit. In: Biennial Research Report No.1 for 1977–78. Maroochy Horticultural Research Station, Queensland Department of Primary Industry, Brisbane, Australia, pp. 71–75. Correa, S.L., Ruggiero, C. and Olivera, J.C. (1979) Propagation of yellow passion fruit by graftage. Proc. Tropical Region of the American Society for Horticultural Science 23, 149–150 Duarte, O. (1997) El cultivo del maracuyá. Escuela Agrícola Panamericana, El Zamorano, Honduras. Duarte, O. and Franciosi, R. (1976) Recent advances in the propagation of some tropical and subtropical fruit species in Peru. Acta Horticulturae 57, 15–20. Duarte, O. and Marín, F. (2002) Comportamiento floral, desarrollo del fruto y propagación sexual de la badea (Passiflora quadrangularis L.). Proceedings of the InterAmerican Society for Tropical Horticulture 46, 8–10. Duarte, O. and Sierra, O. (1997) Efecto de la polinización manual en maracuyá amarillo (Passiflora edulis f. flavicarpa) en El Zamorano, Honduras. Proceedings of the InterAmerican Society for Tropical Horticulture 41, 166–168. Duarte, O., Huete, M. and Magaña, A. (1997) Efecto de la densidad de plantación en la producción de maracuyá amarillo (Passiflora edulis f. flavicarpa) en su primer y segundo ciclo de producción en El Zamorano, Honduras. Proceedings of the InterAmerican Society for Tropical Horticulture 41, 169–171. Farlow, P.J., Winks, C.W., Lanham, T.E. and Mayers, P.E. (1984) Genetic improvement in passion fruit. In: Research Report 3 for 1981–1983. Maroochy Horticultural Research Station, Queensland Department of Primary Industry, Brisbane, Australia, pp, 96–98. George, A. and Paull, R.E. (2008) Passifloraceae, Passiflora edulis Passion fruit. In: Janick, J. and Paull, R.E. (eds) The Encyclopedia of Fruit and Nuts. CAB International, Wallingford, UK, pp. 586–595.

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Grech, N.M. and Frean, R.T. (1986) Preliminary comparisons as to tolerance of three Passiflora species to Fusarium oxysporum PV. passiflorae and Phytophthora parasitica. In: CSFRI Symposium - Research into Citrus and Subtropical Crops. Citrus and Subtropical Fruit Research Institute, Nelspruit, South Africa p. 49 (abstract). Haddad, G.O. and Figueroa, R.M. (1972) Studies on flowering and fruiting in Passiflora quadrangularis. Agronomía Tropical (Venezuela) 22, 483–496. Hardin, L.C. (1986) Floral biology and breeding system of the yellow passion fruit, Passiflora edulís f. flavicarpa. Proceedings of the Interamerican Society for Tropical Horticulture 30, 35–44. Ito, P.J. (1978) ‘Noel’s Special’ passion fruit. HortScience 13, 197. Jan, F.J. and Yeh, S.D. (1995) Purification, in situ localization, and comparative serological properties of passion-fruit woodiness virus-encoded amorphous inclusion protein and two other virus proteins. Phytopathology 85, 64–71. Joubert, A.J. (1984) Pruning of granadillas. G.1. Farming in South Africa. Citrus and Subtropical Fruit Research Institute, Nelspruit, South Africa. Knight, R.J. Jr (1980) Origin and world importance of tropical and subtropical fruit crops. In: Nagy, S. and Shaw, P.W. (eds) Tropical and Subtropical Fruits. AVI Publishing, Westport, CT, pp. 1–120. Manders, G., Otani, W.C., d’Utra Vaz, F.B., Blackhall, N.W., Powers, J.B. and Davey, M.R. (1994) Transformation of passion-fruit (Passiflora edulis f. flavicarpa Degener.) using Agrobacterium tumefaciens. Plant Cell Reports 13, 697–702. Manica, I., Ritzinger, R., Koller, O.C., Riboldi, J., Ramos, R.M. and Rodrigues, A.E.C. (1985) Effect of six thicknesses of planting on the production of passion fruit (Passiflora edulis f. flavicarpa Deg.) during its third year in Viamao. Río Grande do Sul, Brazil. Fruits 40, 265–270. Martin, F.W. and Nakasone, H.Y. (1970) The edible species of Passiflora. Economic Botany 24, 333–343. Martínez, M.M. (1981) La badea. Secretaria de Agricultura y Fomento, Cali, Valle, Colombia. McCarthy, G.J.P. (compiler) (1982) Passion fruit. In: A Handbook of Plant Diseases in Color. Vol. 1 (2nd edn). Information Publication Q182011, Queensland Department of Primary Industry, Brisbane. Menzel, C.M. and Simpson, D.R. (1988) Effects of continuous shading on growth, flowering, and nutrient uptake of passion fruit. Scientia Horticulturae 35, 77–82. Menzel, C.M. and Simpson, D.R. (1994) Passion fruit. In: Schaffer, B. and Anderson, P.C. (eds) Handbook of Environmental Physiology of Fruit Crops. Vol II. Subtropical and Tropical Crops. CRC Press, Boca Raton, FL, pp. 225–241. Menzel, C.M., Simpson, D.R. and Dowling, A.J. (1986) Water relations in passion fruit: effect of moisture stress on on growth, flowering and nutrient uptake. Scientia Horticulturae 29, 239–249 Menzel, C.M., Simpson, D.R. and Winks, C.W. (1987) Effect of temperature on growth, lowering, and nutrient uptake of three passion fruit cultivars under low irradiance. Scientia Horticulturae 31, 259–268. Menzel, C.M., Winks, C.W. and Simpson, D.R. (1989) Passion fruit in Queensland. 3. Orchard management. Queensland Agricultural Journal 115, 155–164. Menzel, C.M., Hayden, G.F., Doogan, V.J. and Simpson, D.R. (1993) New standard leaf nutrient concentrations for passion fruit based upon seasonal phenology and leaf composition. Journal of Horticultural Science 68, 215–229.

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Morton, J.F. (1987) Fruits of Warm Climates. Creative Resource Systems Inc., Winterville, North Carolina, pp. 320–330. Nakasone, H.Y., Hirano, R. and Ito, P.J. (1967) Preliminary Observations on the Inheritance of Several Factors in the Passion fruit (Passiflora edulis Sims and forma flavicarpa Deg.). Hawaii Agricultural Experiment Station Progress Report 161. University of Hawaii, Honolulu, Hawaii. Nakasone, H.Y., Aragaki, M. and Ito, P. (1973) Alternaria brown spot tolerance in passion fruit. Proceedings of the American Society for Horticultural Science 17, 159–165. Ruggiero, C., Lam-Sánchez, A. and Banzatto, D.A. (1976) Studies on natural and controlled pollination in yellow passion fruit (Passiflora edulis f. fíavicarpa Deg). Acta Horticulturae 57, 121–124. Ruggiero, C., Sao José, A.R., Volpe, C.A., Olivera, J.C. de., Durigan, J.F., Baumgartner, J.G., Silva, J.R.da., Nakamura, K., Ferreira, M.E., Kavati, R. and Pereira, V. de P. (1996) Maracujá para Exportação. Aspectos Técnicos da produção Ministerio da Agricultura, do Abastecimento e da Reforma Agraria, Secretaria de Desenvolvimento RuralSDR, FRUPEX, EMBRAPA – SPI, Brasilia, Brazil. Seale, P.E. and Sherman, G.D. (1960) Commercial Passion fruit Processing in Hawaii. Circular 58, Hawaii Agricultural Experiment Station, University of Hawaii. Honolulu, Hawaii. Shiomi, S., Wamocho, I.S. and Agong. S.G. (1996) Ripening characteristics of purple passion fruit on and off the vine. Postharvest Biology and Technology 7, 161–170. Shyy, H.T., Fang, T.T. and Chen, H.E. (1987a) Studies on picking maturity of passion fruit. I. Effect on the general quality of fruit juice. Journal of the Chinese Society for Horticultural Science 33, 51–67. Shyy, H.T., Fang, T.T. and Chen, H.E. (1987b) Studies on picking maturity of passion fruit. II. Effect on the carbohydrate content of juice. Journal of the Chinese Society for Horticultural Science 33, 68–81. Staveley, G.W. and Wolstenholme, B.N. (1990) Effects of water stress on growth and flowering of Passiflora edulis (Sims) grafted to P. caerulea L. Acta Horticulturae 275, 551–558. Storey, W.B. (1950) Chromosome numbers of some species of Passiflora occurring in Hawaii. Pacific Science 4, 37–42. Vargas, O., Alix, C., Lobo, A.D. (authors), Duarte, O. and Sanchez, J. (technical reviewers) (1999) Frutales y Condimentarias del Trópico Húmedo. CURLA; PDBL; AFE/COHDEFOR; DICTA; SETCO; PROFORFITH, La Ceiba, Honduras. Villiers, E.A. de. (1982) Granadilla pests. H.1. Farming in South Africa. Citrus and Subtropical Fruit Research Institute, Nelspruit, South Africa. Watson, D.P. and Bowers, F.A.I. (1965) Long days produce flowers on passion fruit. Hawaii Farm Science 14, 3–5. Wenkam, N.S. (1990) Foods of Hawaii and the Pacific Basin, Fruits and Fruit Products, Raw, Processed, and Prepared, Vol. 4. Composition. Research Extension Series No. 110, College of Tropical Agriculture and Human Resources, University of Hawaii, Honolulu, Hawaii.

9 PALMS

The palms (family Palmae) have been classified into 200 genera in six subfamilies (Uhl and Dransfield, 1988). The subfamilies are separated on four major characteristics: leaf form; number of empty bracts subtending the inflorescence; flower arrangement; and the number and form of carpels in the gynoecium. The fossil record attests to the diversity of palm morphology and ecology, and shows palms to be the one of the oldest recognizable families of monocotyledons. Most palms grow in non-seasonal or mildly seasonal climates, with the rate of the phases of development determined by the environment. Numerous palms are used by humans, but only a small number have taken on significant commercial importance. Palms are regarded as multipurpose trees, with their many products including include oil (e.g. Elaeis guineensis, African oil palm; Cocos nucifera, coconut), waxes (e.g. Copernicia prunifera, carnauba wax), fiber (e.g. Cocos nucifera, coconut coir, Calamus spp., rattans), food (e.g. Cocos nucifera, coconut; Phoenix dactyliferas, date; Bactris gasipaes, peach palm or pejibaye; Salacca zalacca, salak; Nypa frutican, nipa palm, water coconut; Arenga pinnata, sugar palm; Borassus flabellifer, palmyra or toddy palm), narcotics and medicines (e.g. Areca catechu, betel nut), thatch and ornamentals (numerous species). In the food category, besides fruit, products include dried foods, palm hearts (the edible portion of the growing terminal bud), seed, sap (also fermented into wine and distilled into spirits), sugar and starch (sago). This chapter discusses only two palms that provide fresh fruit: coconut and salak. These are used as examples of the diversity of palms.

© Paull and Duarte 2012. Tropical Fruits, 2nd Edition, Volume II (R.E. Paull and O. Duarte)

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COCONUT Introduction Coconut (Cocos nucifera Linn.) is also known as coco and cocotero (Spanish), cocotier (French), kerala (India), tennai (Tamil), pol (Sinhala) and niu (Hawaiian). Its fruit is used fresh at both the immature and mature stages. The genus Cocos is monotypic, containing only the highly variable C. nucifera Linn. Previously the genus contained over 30 other species that occurred in Central and South America, but these have now been reassigned to several other genera. No truly ‘wild’ coconuts are known. The genus Cocos occurs within the Arecoideae subfamily, tribe Coroeae, as do peach palm, oil palm and betel nut. Area of origin and distribution The coconut palm is found throughout the tropics at low elevations. Two centers of origin were originally considered: south-east Asia–Melanesia, and Central and South America. South-east Asia has the greater diversity of types, with numerous local names and uses. There are also unique insect and crab associations in south-east Asia–Melanesia that attest to a long association. Coconut cultivars on the Pacific coast of tropical America, from Mexico to Peru, are indeed distinct from those on the coasts and islands of the Caribbean and the Atlantic coasts of South America and West Africa, suggesting the ends of eastward and westward movement. From the 16th century onwards, Portuguese and later Spanish shipments and introductions could account for coconuts in Africa, the Caribbean and the Atlantic coast of the Americas. The closest botanical relatives of coconut (once classified as other Cocos species) are found in South America, southern Africa and Madagascar, raising the possibility that the true center of origin for Cocos was at the conjunction of South America and southern Africa when those two continents were part of the Gondwana super-continent. Natural dispersal of ancestral coconut palm can account for the predominance of coconut cultivars with ‘wild-type’ attributes on some tropical coasts and remote islands from the Indian Ocean to the mid-Pacific. Subsequently, domestication in South-east Asia and the south-west Pacific, followed by introgression of wild and domestic types, may have led to human dissemination inland, upland and by boat to coastlines to which the wild type could not float. Coconuts possibly moved to New Guinea and Polynesia with humans or by drifting.

Ecology The numerous useful products obtained from the palm and its fruit have led to its wide cultivation in the tropics. It is commercially grown in the warm

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tropics along sea coasts with an adequate water supply, as well as inland, between 23°N and 23°S latitudes. Soil Although the palm is grown on a wide range of soil types, it produces its best yields on rich river alluvial deposits with good drainage. In most tropical countries, it grows on beach sands with low nutrient levels. In these sandy conditions, coconut requires higher land or fresh water swamps to carry nutrients via percolation toward the beaches. Management of coconuts on clay soil is difficult, as good drainage is essential. Soil pHs of acid clays (pH 5.0) to coral-derived sands (pH 8.0) are tolerated. Climate RAINFALL It takes about 44 months from flower primordium initiation to fruit

maturity, including the 12 months from anthesis to fruit maturity. Drought or an extended dry season of 3 months in a row leads to inflorescence abortion, button shedding, premature nut fall and low final nut yield (Fig. 9.1). Hence, rainfall in the first 3 months of nut development determines crop size 12 months later. The effects of prolonged drought can persist for up to 30 months. Total rainfall between 1300 and 2300 mm/year is required for good production, although the pattern of rainfall is more important than the total amount. A mean temperature of 27°C and diurnal variation of 6–7°C is considered optimum. These conditions are found on tropical sea coasts, where the sea acts as a buffer against rapid temperature changes. The palm is killed by frost and inflorescence abortion occurs at low non-freezing temperatures (