A treasure to be plucked
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CTA. 2005. A treasure to be plucked. Spore 116. CTA, Wageningen, The Netherlands.
Permanent link to this item: http://hdl.handle.net/10568/47966
Internet URL: http://spore.cta.int/images/stories/pdf/old/spore116.pdf
Though undervalued in the past, leafy vegetables are a key ingredient in the diets of ACP countries. Recently, researchers have shown strong interest in these traditional greens for their high nutritional value and economic potential.
Traditional leafy vegetables belong to the group of so-called orphan crops which tropical research has rediscovered in recent years, drawn by their nutritional and economic value. In manuals, they have long been eclipsed by green vegetables of European origin, such as cabbage and lettuce, even though these have far less nutritional content. These days, leafy vegetables are seen as an ally in the fight against hidden hunger , the term used to describe deficiencies of micro-nutrients such as vitamin A and minerals like iron, which prevents anaemia. Whether they be wild or cultivated, and produced by lianas, tubers or trees, leafy vegetables offer populations with limited access to meat or fish a rich source of protein, which is essential for pregnant women and breastfeeding mothers, as well as for young and growing children. The leaves of Moringa oleifera are rich in protein (see Spore 106). Dry cassava leaves contain up to 36.8% protein, while amaranthus and Ceylon spinach both contain 25%, compared with dried haricot beans, which have just 23.3%. These vegetables are particularly useful in times of food shortages or between harvests. A culinary heritage Though ignored by most agronomy manuals, these traditional plants still feature strongly in the dishes and home gardens of ACP countries. When cooked, leafy vegetables also known as bredes in the Indian Ocean and Pacific islands play an important role in the preparation of famous dishes and sauces served as an accompaniment to cereals and tubers. In Cameroon, bitter leaves, a dish based on the leaves of Vernonia and peanut, is part of the culinary heritage, whilst in Congo, saka saka is made with cassava leaves. In the Pacific Islands, amaranthus, cassava or hibiscus leaves are cooked in coconut milk to make laplap. The women who grow or harvest these leaves are also familiar with their valuable therapeutic properties. Consumption of these plants is closely linked to culture. In certain Pacific islands, some leaves will be highly prized, while on a neighbouring atoll they may be spurned and used only as animal fodder. In Tanzania, leaves of Solanum villosum, a highly sought after variety of nightshade, costs twice the price of the more common amaranthus leaves. For the past 12 years, the Secretariat of the Pacific Community (SPC) has been trying to educate people on the benefits of leafy vegetables. Campaigns have been conducted in countries of the South to explain, for example, that cooking these green vegetables for a shorter time helps to preserve their vitamin content and nutritional value. From the bush to the towns Lack of knowledge about these indigenous plants is mainly due to the fact that there are a great many of them, and that they often grow spontaneously and in very small areas. But rural populations in particular have long known of and cultivated them. In Africa, urbanisation has changed things and given rise to what are often quite sizeable markets selling the leafy vegetables best suited to transportation. Since freshness is crucial, cultivation of leafy vegetables has also developed in towns and peri-urban settings. A study carried out by the International Institute of Tropical Agriculture (IITA) on urban households in Yaoundé revealed that traditional green vegetables are most frequently grown by poor families (see Spore 110). Total production of leafy vegetables in Cameroon was estimated to be 93,600 t in 1998, with 21,549 t made up of Vernonia. In Senegal, leafy vegetables account for as much as 50 to 85% of the household budget for some farmers. In sub-Saharan Africa, these plants are sold at local but also at regional markets. Leaves from the liana Gnetum africanum (better known as okok in English-speaking countries or eru in Cameroon) are traded in significant quantities between Cameroon and Nigeria, where, highly prized and over-harvested, they have all but disappeared. Fresh, dried or sometimes frozen, some traditional leafy vegetables can also be found in Europe and North America. But according to a recent study, these products, which are symbols of cultural identity are generally confined to Afro-Caribbean shops and restaurants, used mainly by ethnic communities. Assets to be used According to Kenyan ethnobotanist Patrick Maundu, no fewer than one thousand African plants could be consumed as leafy vegetables. In ACP countries, only around 15 varieties are grown and sold on any significant scale. Some wild species, such as Gnetum, which were over-harvested and threatened with extinction, are now being domesticated in Cameroon and Nigeria. But before they can be cultivated, the long process of collecting and conserving ecotypes must be carried out, as well as work to improve varieties and develop techniques for farmers. Researchers from Cameroon, Kenya, Senegal, South Africa and The Gambia are working on all these tasks with the support of Future Harvest (an organisation which groups16 international research institutes). Many of these plants have the advantage of growing very quickly (in less than 1-2 months) in tropical climates and require very little in the way of treatment, compared with other market garden species. These are important plus points at a time when HIV/AIDS is depriving many African countries of its labour force. They can also be easily grown, especially by women, on small plots and used to feed the household or to generate extra income. In addition to their role in cultivating wild leafy vegetables, the job of harvesting and marketing the vegetables has also traditionally fallen to women.