MANGO GROWING IN KENYA JURGEN GRIESBACH WORLD AGROFORESTRY CENTRE ISBN 92 9059 149 8 Cover photo: Sensation cultivar, Jiirgen Griesbach Cultivar photos: Jiirgen Griesbach Editing: Anne Marie Nyamu and Tony Simons Design: Clemak Investments Ltd © ICRAF 2003 World Agroforestry Centre (ICRAF) PO Box 30677-00100 Nairobi, Kenya Tel: +254 2 524 000, via USA +1 650 833 6645 Fax: +254 2 524 001, via USA +1 650 833 6646 Email: [email protected] Internet http://www.worldagroforestrycentre.org Printed by: Kul Graphics Nairobi, Kenya CONTENTS Foreward iv Preface v Introduction 1 Uses and food value 2 Botany. 3 Propagation 4 Establishment 5 Maintenance 6 Production 6 Maturity. 7 Flower induction 11 Pests and diseases 12 Mango fruit fly. 12 Mango seed weevil 13 Powdery mildew. 14 Anthracnose 14 Description of mango cultivars 17 Alphonso 18 Apple 20 Arumanis 22 Batawi 24 Boribo 26 Carabao 28 Chino 30 Dodo 32 Gesine 34 Golek 36 Haden 38 Heart 40 Irwin 42 Keitt 44 Kensington 46 Kent 48 Madoe 50 Matthias 52 Maya 54 Ngowe 56 Nimrod 58 Parwin 60 Peach 62 Sabine 64 Sabre 66 Sensation 68 Smith 70 Tommy Atkins 72 'Van Dyke 74 Zill 76 Zillate 78 Further reading 80 Glossary. 82 Appendix 1: Some characteristics of Kenya-grown mango cultivars 86 Appendix 2: Average rainfall figures (mm) and temperature data (°C) of selected stations located in mango growing provinces 92 Appendix 3: Provincial mango production statistics 93 Appendix 4: Main supply seasons of selected mango exporters 95 Appendix 5: Export market statistics figures for mango from Kenya by sea and air (kg and t) 96 Appendix 6: Common horticultural insecticides/fungicides, their recommended pre-harvest intervals and range of effectiveness 97 Appendix 7: List of registered fruit tree nurseries 101 FOREWORD The word fruit is derived from the Latin word fructus which means enjoyment. Of all fruits enjoyed throughout the world few are as popular or universally acceptable as the mango. In fact the only tropical fruit which outranks it is the banana. With nearly US$ 500 million worth of mangoes exported each year and 40 times that amount consumed in the countries of production, its role in income generation and household food security is evident. The dual roles of the mango of providing household nutrition and economic development opportunities overlap with the goals of the World Agroforestry Centre (ICRAF). Established in 1978, ICRAF has evolved from a promotional council to an international scientific research institute to a worldwide centre addressing research and development issues of trees on farms. In tree species prioritisation studies with smallholder farmers, fruit trees routinely emerge as being highly popular although their cultivation is sometimes seen as being highly knowledge intensive. Whilst many efforts are underway to domesticate wild indigenous species in Africa, the regal mango which has been domesticated for 4000 years deserves as much if not more attention. Kenya is a country with a strong agriculture industry, although the horticulture component of this, with the exception of floriculture, has been under-developed. With a view to increasing the mango industry in Kenya and similar countries ICRAF is pleased to be able to publish this booklet drawing on the decades of experience in East Africa of its author, Jiirgen Griesbach. The production and publication of this booklet was made possible through project grants of the Ministry of Foreign Affairs (Education and Development Division) of the Netherlands Government and the Department for International Development (DFID) of the United Kingdom. Fruit preferences are as much a cultural phenomenon as they are an agroclimatic or a physiological one. We are confident that the practical information contained in this booklet will engender a greater mango planting culture in Kenya and neighbouring countries. In time it is hoped this will boost export earnings and contribute to rural and urban nutrition through fresh and dried fruits. Enjoy the mango fruit and enjoy reading this book. Tony Simons, PhD Principal Tree Scientist World Agroforestry Centre PREFACE The mango industry in Kenya has expanded considerably over recent years, not only in size but also in the geographical location of commercial and homestead plantings. No longer is commercial mango cultivation restricted to the Coast Province, as significant plantings of improved cultivars now also exist in the Eastern and Central provinces, among other regions. As a result of this expansion, the mango fruit is becoming more popular with the local population. Despite this increasing popularity, only a few consumers and potential growers are familiar with the characteristics of the many different cultivars of mango that are now grown and available in the country (see Appendix 1). The aim of this booklet is chiefly to familiarize readers with the details of the more common cultivars that are potentially suitable for commercial and backyard production. Their respective origins, characteristics, advantages and disadvantages are discussed. In addition, information regarding propagation, and establishment and maintenance of an orchard of this important fruit species is given. INTRODUCTION Although the mango tree is not indigenous to Kenya, it has been cultivated in the Coast Province for centuries. Traders in ivory and slaves brought seed into the country during the 14th century. Mango trees were reported in Somalia as early as 1331. The mango is one of the most important fruit crops in the tropical and subtropical lowlands. It is native to India, Bangladesh, Myanmar and Malaysia, but can be found growing in more than 60 other countries throughout the world (Salim et al., 2002). The mango is best adapted to a warm tropical monsoon climate with a pronounced dry season (>3 months) followed by rains. However, information from other countries indicates that crops cultivated for a long time over an extended area show a high degree of diversity due to varied environmental influences. This was likely also true for the mango seedlings first introduced in Kenya which were all polyembryonic. They can be multiplied by seeding and generally produce true-to-type progeny. Some of these are still productive, e.g. along the Tana River, and some of them have been given names which to this day are still valued. Kitoovu, Kimji, Klarabu, Punda and Mayai are of poor quality but better known are cultivars like Apple, Ngowe, Boribo, Batawi and Dodo. Of these, a few have steadily lost ground to a generation of cultivars introduced in the 1970s and 1980s distinguished by greater resistance to anthracnose (Colletotrichum), powdery mildew {Oidium), their very attractive colour and good shelf life. USES AND FOOD VALUE The mango—because of its attractive appearance and the very pleasant taste of selected cultivars—is claimed to be the most important fruit of the tropics. It has been touted as 'king of all fruits' but has also been described as a 'ball of tow soaked in turpentine and molasses' by critics! It is one of the most delicious fruits there is, although it has undesirable features including coarse fibrous strands through the flesh and the pungent and turpentine flavours of some cultivars. Fruits from the scattered mango production areas are mainly consumed locally. During the last 20—30 years, commercial mango production was developed based on locally adapted and newly imported cultivars. This has seen the area under mango cultivation in Kenya rise from 500 ha in 1970 to approximately 15,000 ha in 2000 (source: Annual Report, Ministry of Agriculture, Nairobi). There is a great diversity of mango fruit types which permits considerable manipulation for various purposes and markets: juice, chutney, pickles, jam/jelly, fresh fruit, canned and/or dried fruit etc. Given the multiple products, it is therefore a potential source of foreign exchange for a developing country; it is also a source of employment for a considerable seasonal labour force. In addition to income opportunities, the mango is noted for combating nutritional disorders. The mango compares favourably in food value with both temperate and tropical fruits. Indeed the fruit contains almost all the known vitamins and many essential minerals. Studies have shown that one mango fruit can provide a large proportion of the daily human requirements of essential minerals, and vitamins (see Table below). The calorific value of mango is mostly derived from the sugars. It is as high as that of grapes and even higher than that of apple, pears or peaches. The protein content is generally a little higher than that of other fruits except the avocado. Mangos are also a fairly good source of thiamine and niacin and contain some calcium and iron. Calories and nutrients per 100 g edible portion Fruit Calories Protein Calcium Iron Vitamin A Thiamine Vitamin C (g) (mg) (mg) (IU) (mg) (mg) Orange 53 0.8 22 0.5 0.05 40 Banana 116 1.0 7 0.5 100 0.05 10 Mango 63 0.5 10 0.5 600 0.03 30 Source: Piatt (1962). Minimum daily vitamin and mineral requirements for healthy people Vitamin A (IU) = 2500 Vitamin C (mg) = 60 Thiamin (mg) = 1.5 Niacin (mg) = 19 Iron (mg) = 18 Calcium (mg) = 1000 Source: Mervyn (2000). BOTANY The mango is a member of the family Anacardiaceae. This family comprises many other valuable trees such as the cashew and the pistachio nut. The genus Mangifera includes 25 species (Mabberly, 1997) with edible fruits such as Mangifera caesia, M. foetida, M. odorata and M. pajang, although M. indica, the mango, is the only species that is grown commercially on a large scale. Worldwide mango cultivation now covers approximately 2.9 million hectares (FAO, 2001) and earns nearly US$ 500 million in export revenues. There are two races of mango—one from India and the other from Southeast Asia. The Indian race is intolerant of humidity, has flushes of bright red new growth that is subject to powdery mildew and anthracnose and bears mono-embryonic fruit of high colour and regular shape. The Southeast Asian race is tolerant of excess moisture, has pale green or red new growth and resists powdery mildew. Its polyembryonic fruit is pale green and of an elongated kidney shape. The mango is a deep-rooted, evergreen plant which can develop into huge trees, especially on deep soils. The height and shape varies considerably among seedlings and cultivars. Under optimum climatic conditions, the trees are erect and fast growing and the canopy can either be broad and rounded or more upright. Seedling trees can reach more than 20 m in height while grafted ones are usually half that size. The tree is long-lived with some specimens known to be over 150 years old and still producing fruit! The mature leaves are simple, entire, leathery, dark green and glossy; they are usually pale green or red while young. They are short-pointed, oblong and lanceolate in shape and relatively long and narrow, often measuring more than 30 cm in length and up to 13 cm in width (Salim et al., 2002). New leaves are formed in periodic flushes about two to three times a year. The greenish-white or pinkish flowers are borne in inflorescences—usually placed terminally on current or previous year's growth—in large panicles of up to 2000 or more minute flowers. Male flowers usually outnumber the bisexual or perfect flowers. Generally, flowering in Kenya lasts from about late July to early November, depending mostly on weather conditions. At the coast it is not uncommon to find individual trees flowering as early as February and March. Pollinators are usually flies, rarely bees or nectivorous bats. Pollen cannot be shed in high humidity or rain as this might prevent pollination and fruit setting. Mangos are self-fertile, thus a single tree will produce fruits without cross-pollination. Mango fruits of the various cultivars differ greatly in shape, size, appearance and internal characteristics. The fruit is a fleshy drupe, varying in size from 2.5 to 30 cm long, may be kidney-shaped, ovate or round and weigh from approximately 200 g to over 2000 g. The leathery skin is waxy and smooth and when ripe entirely pale green or yellow marked with red, depending on the cultivar.