ABSTRACT
The development and deployment of hybrid corn ranks fi rst among the applications of science to food production, although the contributions of fertilizers, herbicides, seed treatments, and improved agronomic practices can hardly be ignored. The productivity of the fi rst practical hybrids was so impressive that open pollinated corn virtually disappeared within 15 years in areas where hybrids were available. Yet on a percent improvement basis, native American Indians-from Argentina to Canada, especially those from Mexico and Central America-had a still greater impact. Corn was domesticated in Mexico or adjacent Central America, and maximum yields were increased from kernels per acre to about 50 bushels per acre over a period of perhaps 10,000 years (Wallace and Brown 1988). Midwestern farmer-breeders probably added another 25 bushels/acre. Hybrid corn has more than doubled that productivity in about 80 years and has increased average yields by a factor of fi ve, with genetic improvement accounting for more than half of such increases (Castleberry et al. 1984; Russell 1984; Duvick 2005).
