TROPICAL VEGETABLE PRODUCTION This page intentionally left blank TROPICAL VEGETABLE PRODUCTION Raymond A.T. George Former Senior Lecturer University of Bath UK and Consultant to the United Nations Food and Agriculture Organization Rome Italy CABI is a trading name of CAB International CABI Head Offi ce CABI North American Offi ce Nosworthy Way 875 Massachusetts Avenue Wallingford 7th Floor Oxfordshire OX10 8DE Cambridge, MA 02139 UK USA Tel: +44 (0)1491 832111 Tel: +1 617 395 4056 Fax: +44 (0)1491 833508 Fax: +1 617 354 6875 E-mail: [email protected] E-mail: [email protected] Website: www.cabi.org © Raymond A.T. George 2011. 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 George, Raymond A. T. Tropical vegetable production / Raymond A.T. George. p. cm. Includes bibliographical references and index. ISBN 978-1-84593-753-9 (alk. paper) 1. Tropical vegetables–Developing countries. I. C.A.B. International. II. Title. SB324.56.G46 2011 635.0913–dc22 2010020579 ISBN: 978 1 84593 753 9 Commissioning editor: Sarah Hulbert Production editor: Shankari Wilford Typeset by AMA Dataset, Preston, UK. Printed and bound in the UK by the MPG Books Group. Contents Preface vii Acknowledgements x PART 1 PRINCIPLES AND PRACTICE OF TROPICAL VEGETABLE PRODUCTION 1 Introduction 1 2 Site, Topography, Soils and Water 9 3 Site Management, Seeds and Types of Cultivars 25 4 Support for Farmers 38 5 Crop Preparation and Management 46 6 Reducing Pre- and Postharvest Losses and Marketing Surpluses 60 PART 2 TROPICAL VEGETABLE CROPS 7 Alliaceae – Onions and Related Crops 73 8 Cruciferae – Crucifers 83 9 Cucurbitaceae – Cucurbits, the Vine Crops 93 10 Solanaceae – Tomatoes and Related Crops 113 v vi Contents 11 Leguminosae – Beans and Related Crops 132 12 Leafy Vegetables 147 13 Araceae, Convolvulaceae, Dioscoreaceae, Euphorbiaceae – Tropical Tubers 162 14 Andean Tubers and Roots and Crops of the Lamiaceae and Apiaceae 176 15 Gramineae and Cyperaceae 187 Appendix 1 Indigenous Species Not Dealt With in the Main Text 195 Appendix 2 International Research Institutes 197 References 199 General Index 203 Index of Species 219 Preface Despite efforts to improve and increase food production and supply by institutional developments during recent decades, there still remains a major food security problem in many parts of the world, especially in the tropics and subtropics. It is now being increasingly recognized and appreciated that a large propor- tion of populations in developing countries are reliant on subsistence farm production for their day-to-day food supply and longer-term food security. This food source is frequently referred to as the ‘informal sector’ of food production. The recognition of this fact was an important outcome of the G8 Conference held in Italy in 2009 and it was also emphasized by President Barack Obama during his address in Accra, Ghana, on 10 July, 2009. The President also stated that ‘Aid is not an end in itself. The purpose of foreign assistance must be creating the conditions where it is no longer needed.’ One of the most important aspects of subsistence farming is the day-to-day availability of fresh and stored vegetables and their products. Despite what has been achieved in the past by national and international programmes it is very apparent that we must do signifi cantly more to ensure that the subsistence farm- ers are able to not only increase their vegetable productivity and food security but that their improved food supply becomes sustainable thereby improving the health, well-being and education of their dependents and overall reduction of poverty. Many of us who have been involved with agronomy and related subjects in tropical environments believe that more effort has to be given to improving food security from the bottom up, that is by improving the informa- tion and material inputs such as improved seed, planting materials and technol- ogy available to small farmers. There is an urgent need for more farmer training and research which is of direct relevance to improving production on the subsistence farms. The overall environment is a very topical global subject, coupled with this is the established but still rapidly developing topic of Integrated Pest Management vii viii Preface (IPM). There is a need for farmer training to assist the recognition and adoption of this concept therefore helping the technology transfer of this and other exciting improvements that must be made down to village level. A subsistence farmer can be defi ned as one who attempts to produce enough food from a plot of land to sustain the farmer and their dependents throughout the year. By this defi nition there are no surplus crops or products to market and the farmer is sometimes referred to as a resource poor farmer. Subsistence farm- ers’ main concerns are food security and minimizing risk. They have to rely on one site for continuity of their food supply in contrast to members of the popula- tion who are able to purchase from markets. The gender issue is a very important aspect of subsistence farming. Approx- imately 50% of food crops in Asia are produced by women, while in Africa women provide about 60% of the agricultural labour force and up to 80% of the total food-producing labour force (FAO, 1998). In addition many women are also responsible for producing the food consumed by their families. It is extremely important from the women farmers’ points of view and for their welfare that they become sustainable farmers with appropriate and proportionate opportunities, including access to extension advice and related research fi ndings. This volume is in two parts. Part 1 comprises six chapters concerning the principles and practice of tropical vegetable production. In Part 2 the crops have been mainly dealt with according to their taxonomy as botanical families, either as single or groups of families per chapter. Examples of the indigenous species which can be regarded as important sources of edible vegetative materials which are not dealt with in the main text have been listed in Appendix 1. Contact details of the main international research stations are provided in Appendix 2. A textbook cannot remain up to date with changes and new developments in crop protection chemicals because pesticides are continually being withdrawn and replaced, in some cases their formulation and approved use is modifi ed, and recommended usage is likely to differ from one country to another. This book has been written with the hope and purpose that it will be used by technical, college and university students during their studies of horticulture, crop production and agriculture; it is also for students on other allied courses and agriculturists who fi nd themselves needing more vegetable-orientated informa- tion in the course of their professional activities. My purpose and objective is to humbly but whole-heartedly assist in the production of extension, advisory and research staff and offi cers who will be the core of trainers, advisors, researchers and extension workers in tropical and subtropical countries. I am very grateful to Peter R. Thoday for the very useful discussions and encouragement while I was formulating the scope of the book and for his con- structive comments from time to time during its writing. My thanks to Sarah Hulbert, the Commissioning Editor at CABI, for her patience and ever ready advice while I was preparing the manuscript, also Kath- erine Dalton, Editorial Assistant, and Shankari Wilford, Production Editor, for so kindly and effi ciently dealing with the production side. I am very grateful to Pris- cilla Sharland who so diligently and effi ciently copy-edited the manuscript. Special thanks are due to our family, Andrew, Christopher, Jane, Joseph and Patrick who helped with the preparation of fi gures and took care of the occasional Preface ix computer mishaps which arose during the 11 months of manuscript production and who also, from time to time, improved my computer literacy. Finally my great appreciation to my wife, Audrey, who over many years has not only tolerated my absences on long-term stays overseas and shorter missions relating to vegetables but has also been very patient while I have been writing this title. Raymond A.T. George Bath, UK May, 2010 Acknowledgements The author is extremely grateful to the following for permission to reproduce photographs: Fig. 2.1 Photograph by kind permission of Lucy E. King, the copyright holder. Fig. 2.3(a) and (b) Photographs by kind permission of Alan Spybey, Director of Technology Development, KickStart (www.KickStart.org), the copyright holder. Figs 5.1, 6.1, 6.2, 8.2(a), 8.2(b), 9.3(a), 10.4, 10.5 and 12.2 Photo- graphs by kind permission of The Real IPM Company (K) Ltd (www.realipm. com), the copyright holders. x 1 Introduction What Is Meant By ‘the Tropics’ in Terms of Vegetable Production? If we take a physical and geographical defi nition of the tropics we fi nd that this area of the world is between the northern limit of the Tropic of Cancer and the southern limit of the Tropic of Capricorn (i.e. between latitudes 25½° N and S of the equator). However, the range of geographical locations suitable for satisfac- tory growth and production of tropical vegetable species can go both beyond and be limited within this defi ned area depending on factors such as rainfall, solar radiation and temperature. The environmental limits which restrict the subsistence farmer also interact with the tropical environment.