Making more of potatoes
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CTA. 1998. Making more of potatoes. Spore 73. CTA, Wageningen, The Netherlands.
Permanent link to this item: http://hdl.handle.net/10568/48963
Internet URL: http://spore.cta.int/images/stories/pdf/old/spore73.pdf
A staple crop which can yield four times as many calories per hectare as rice, or five times as many as wheat, is enjoying a consumer success that has encouraged many farmers to increase production. The Irish potato (Solanum tuberosum) is becoming...
A staple crop which can yield four times as many calories per hectare as rice, or five times as many as wheat, is enjoying a consumer success that has encouraged many farmers to increase production. The Irish potato (Solanum tuberosum) is becoming ever more popular and, provided that the quality meets the expected high standards, the commercial rewards of a buoyant market are there for the taking. If advertising copywriters were given the opportunity to promote the raw, unprocessed potato, they would be pleased to adopt the slogan that potatoes are packed full of goodness. Rich in vitamins and minerals, protein (concentrated in the skin) and calories, and almost fat-free, potatoes need no advertising, as the quadrupling of production in Africa over the past 35 years testifies. According to FAO, growth in potato production on the continent has been consistently higher than population growth. This is an exceptional record for a food crop, many of which have fallen behind or, at best, kept pace with population growth. It is the urban market which has led the demand because potatoes are convenient being quick to prepare and cook, and are adaptable to many different recipes. They can be grown to be sold fresh or for processing, but to-date most production in ACP countries is on a small scale more suited to the fresh market. Approximately 425,000 hectares of potatoes are now being planted in sub-Saharan Africa, both as a cash crop and for household consumption. The increase has been largely due to an increase in area planted rather than in productivity but, where irrigation, fertilizer and good quality planting material are being used to grow potatoes on a commercial scale, yields of 25 tonnes per hectare (South Africa) and 16 tonnes per hectare (Zimbabwe) are being achieved. Elsewhere, for example in the highland areas of eastern and central Africa, where plots are small, cultivation is by hand and inputs, such as chemical fertilizers and fungicides, are rarely affordable; consequently, yields are about half those achieved in southern Africa. In West Africa, potatoes are usually grown on a small scale from imported seed (i.e. tubers, not true seed) and with high levels of inputs; there the market price reflects the high production costs. The most important potato producing countries in sub-Saharan Africa are South Africa, Zimbabwe, Uganda, Ethiopia, Madagascar, Rwanda, Tanzania, Kenya and Cameroon. Although over 150 wild species of potato are found in the Americas, where the plant originated, only one species, Solanum tuberosum, is grown commercially elsewhere. Genes from wild species have been bred into many of the cultivated varieties of potato in order to give them resistance or tolerance to pests and diseases. Potatoes are not immune to the problems that beset any agricultural enterprise. Even where conditions should be ideal, where production is intensive and where there is no shortage of chemical controls designed to cure problems, yields can plummet for one reason or another. Clean propagating material, effective cultivation practices, adequate pest and disease management and proper post-harvest storage facilities are all essential if farmers are to make the most of market opportunities. Threat of blight Late blight (Phytophthera infestans) can turn a field of potatoes brown in just a few days. It is the single most important biotic constraint to potato production in sub-Saharan Africa and is most severe in the tropical highlands of central and eastern Africa. Many of the potato varieties grown have very low levels of resistance to blight but, provided farmers can spray at the first sign, it is theoretically possible to limit the damage. However, the majority of resource-poor farmers in this region have neither the funds, the know-how, nor reliable access to fungicides to enable them to control the disease. There are serious concerns that this disease may become even more of a problem in future. Evidence of this is appearing in the Americas, where strains of the disease are becoming more resistant to the fungicides available. There are reports that, in Central America, farmers are spraying as many as 25 times in a season in an effort to control the disease. There are, as yet, no signs of these highly resistant strains in sub-Saharan Africa, but it would be naïve to assume they could not spread. Seed distribution, especially of new, improved varieties, is problematic in many sub-Saharan African countries. Attempts in the past to establish centralized systems similar to those in place in Europe and North America have largely failed, for a variety of reasons. The International Potato Center (CIP) is currently working with three national potato programmes, in Kenya, Uganda and Ethiopia, to find ways to support farmer-based systems for multiplying and distributing high-quality seed (see box). Future markets The market for processed potatoes is growing as rapidly as the cities in which most fast food consumers live. Manufacturers of potato chips, French fries and other potato-based snacks have their own requirements with regard to the variety, quality and quantity of the potatoes they are prepared to purchase. For processing plants to be economical, producers must be able to supply specific varieties to match the needs for dehydrated potato, crisps or oven-ready chips. Farmers in Africa need have no fear that this market will dry up, if experience elsewhere is a good indicator of trends. It may look unprepossessing as it comes out of the ground but, in one form or another, the Irish potato has style, youth appeal and a rapidly expanding market.