Direct, Cyclic Somatic Embryogenesis of Cassava for Mass Production Purposes

Cassava (Manihot esculenta Crantz) is a perennial shrub of the same family, the Euphorbiaceae, as castor bean (Ricinus communis ) and rubber tree (Hevea brasiliensis ). It is grown for its starch-containing tuberized roots, which are used for human consumption, as animal feed, and as raw material for the starch industry. The centers of diversity are in central and North eastern Brazil, southwestern Mexico, and eastern Bolivia (1 ). Cassava is also grown on the African and Asian continents (2 ). The average yield in the world is 8.8 tonnes/hectare (3 ), which is only a fraction of the potential yield of 90 tonnes/hectare (4 ). One of the reasons for this low yield is the use of cuttings infected with diseases and pests as the starting material.