ABSTRACT
Cocoyam (Xanthosoma spp.) is one of the six most important root and tuber crops widely consumed all over the tropical and subtropical regions of the world (Jennings 1987, Onwueme and Charles 1994, Bown 2000). Edible varieties of this herbaceous monocotyledonous crop are grouped into few species, including the most widely grown X. sagittifolium (L.) Schott. They are mainly cultivated by small-scale farmers (Onwueme and Charles 1994) in Asia, Africa and Latin America (Wilson 1984). The corm and cormels of cocoyam are an important source of carbohydrates for human nutrition or animal feed, but the leaves are also consumed (Nyochembeng and Garton 1998). In spite of the importance of this staple food in many countries, cocoyam has received very little research attention (Goenaga and Heperly 1990), and is regarded as an under-exploited and insuffi ciently studied crop (Nguyen and Nguyen 1987, Giacometti and León 1994, Watanabe 2002).
