Cassava (Manihot esculenta) is a perennial woody shrub with edible roots. It grows in tropical and subtropical areas of the world and is also called yuca, manioc and mandioca, along with many other local names.
The crop has been cultivated in tropical America for probably about 10,000 years. It was introduced to Africa by Portuguese traders during the 16th century and later to Asia, both from Africa and from the Americas. It is now grown in more than 90 countries and provides food and income for 500 million people in the developing world. In large areas of sub-Saharan Africa, and in parts of Latin America and southeast Asia, cassava provides a major daily source of dietary energy.
Genesys lists more than 9,000 accessions of cassava, 75% of them traditional cultivars or landraces. The majority of accessions are maintained as in vitro plants by CIAT in Colombia, with a slightly smaller number at IITA in Nigeria. Both institutes are using cassava genetic resources from their genebanks to breed improved varieties.