Cassava Potential for Bioethanol.

Despite the food-fuel controversy, a number of countries are interested in cassava as a biofuel feedstock due to its economic competitiveness, adaptation to poor soils, and flexible harvest window. China, Colombia, Thailand, and Vietnam have launched cassava bioethanol initiatives. Cassava is not a foodstuff in China, precluding direct food-fuel tradeoffs.  CIAT pursues two breeding objectives to improve the crop for this use: 1) root quality traits that reduce the costs of conversion into ethanol, e.g.  two useful mutants: a recently-discovered amylose-free variant that enhances the hydrolysis of starch into sugar, and another that reduces starch granule size which reduces the quantity of enzymes needed for starch digestion; and 2) recovering  genotypes that  were rejected from breeding programs in the past because of low dry matter content in roots (which creates difficulties in processing starch or chips for animal feed) despite high dry matter yields per hectare (a desired trait for bioethanol production). Agronomic research is also devising systems for year-round root production (within sustainable rotations) to provide a steady feedstock supply to processing plants.