The past, present and future of crop genetic modification.

The introduction of science and technology into agriculture over the past two centuries has markedly increased agricultural productivity and decreased its labor-intensiveness. Chemical fertilization, mechanization, plant breeding and molecular genetic modification (GM) have contributed to unparalleled productivity increases. Future increases are far from assured because of underinvestment in agricultural research, growing population pressure, decreasing fresh water availability, increasing temperatures and societal rejection of GM crops in many countries.