Cassava, a starch-rich plant that has poor protein content and usually poor vitamin content, feeds about 600 million people each day. When cereals can no longer be grown because of soil fertility problems, it is often still possible to grow cassava. It is the third most important source of dietary calories in the tropics, and reliance on the crop is especially high in West and Central Africa.  The International Laboratory for Tropical Agricultural Biotechnology is promoting research to improve cassava productivity and is a leader in developing genetic engineering to improve the quantitative and qualitative traits of this essential food crop.