Claude Fauquet and Denis Fargette

Cassava (Munihor escuknra CrantE; Euphorbiaceae) is the only species in its genus that is cultivated as a food crop. In South America, where it originated. cassava was domesticated 2,0004,000 years B.c., yet only recently has it become distributed worldwide. The Portuguese began importing cassava into the Gulf of Guinea in Africa in the 16th century. In the 18th century, they introduced it to the east coast of Africa and the Indian Oman islands of Madagascar, Rhnion, and Zanzibar. Portuguese ships probably carried cassava to India and Sri Lanka after the mid-18th century. Cassava at first was little appreciated, but since the 19th century it has extended rapidly across Africa (Fig. 1) and is now grown in 39 countries. Cassava is the third largest source of carbohydrates for human food in the world (estimated annual yield is 136 million tons), and Africa is the lrugest center of production (57 million tom were grown on 7.5 million h e c t m in 1985). Cassava is produced for industrial purposes in Brazil and as an export crop in Thailand, but in Africa it is grown primarily for local food consumption. In fact, cassava is the most important food crop grown on the African continent, exceeding yam (Dioscorea spp.), 24 million tons; maize ( 2 h mays L.). 12 d o n tons; and pearl millet (Pennisetum ghw cum (L.) R. Sr.), 9 million tons. Production per hectare averages 5-10 tons, but on the basis of yields at research stations. the potential exceeds 80 tons. In most Africm countries, cassava is grown primarily by traditional farmers, but there are some industria1 plantations in Liberia, Nigeria, and Togo. African farmers usually grow cassava in mono-