Cassava (Manihot esculenta) is a woody shrub and widely cultivated in tropical and subtropical regions in the world. In 2006, total production of the world was 226 million tons in

18.6

million ha of harvested area. The biggest cassava producer is Nigeria and followed by Brazil, Thailand and Indonesia (Fig. 2.8.3). The yield of cassava in Thailand is ranked first and about 21 ton/ha averaged over whole 1.1 million ha of harvested area (Fig. 2.8.4).

Fig. 2.8.3. World leading countries of cassava production in 2006.

Cassava is propagated by stem cutting, which is planted on a soil in a vertical and inclined position. It can grow well even on an infertile soil and is tolerant of drought. Starch-rich tuberous root is harvested by hand around 12 months after planting, but it can be harvested as early as 8 months or as late as 24 months. Starch content of tuberous root in Thailand is about 25%. In Thailand, yield of cassava gradually increases mainly due to the consistent development of better varieties (Fig. 2.8.5). Currently, Rayong 9 with up to 30 ton/ha yield has been distributed since 2006.

Tuberous roots of most varieties contain cyanide and it should be removed by soaking cassava flour. Cassava has been used as a staple source of carbohydrate for human consumption in many tropical countries, as an ingredient in animal feeds, and as a source of starch. Bio-ethanol production from cassava starch is developing. Cassava production of Thailand in 2007 was 27 million tons and the flow chart (Fig. 2.8.6) shows the breakdown of cassava applications in food, feed and fuel.

Fig. 2.8.5. History of cassava statistic in Fig. 2.8.6. Uses of cassava in Thailand. Thailand.