ABSTRACT
Improving cassava productivity requires an understanding of its development as a global crop. Because of its long growing season – usually nine months or more – cassava cultivation is restricted to the tropics and subtropics, where near year-round growth is possible if sufficient water is available. A range of evolutionary, agronomic and commercial factors have defined where and how cassava is grown, how it is used, and the challenges growers face. The crop originated in the Americas and was widely distributed throughout the tropics and subtropics of the western hemisphere before the arrival of Europeans in the fifteenth century (Allem, 1990, 2002; Allem et al., 2001; Olsen and Schaal, 2001; Nassar and Ortiz, 2008). Traders carried it to Africa relatively quickly after Columbus. While the introduction to Asia is not well-documented, it appears that Spanish traders introduced the species from Mexico to the Philippines in the nineteenth century, and independently from Africa to India.
