Maize (Zea mays L.), otherwise known as corn, is a highly unusual, economically important, and genetically well-characterized member of the grass family. It is believed to have originated some 8,000 to 10,000 years ago in the fields of the first agriculturalists of Mexico and Central America. These early farmers carefully selected traits that would ultimately transform the tiny, sparsely seeded spike of a wild grass into the large cob bearing many rows of kernels that we recognize today as an ear of corn.

The success of these early plant breeders was manifested by the spread of corn cultivation throughout the New World, long before the arrival of Europeans. Today, maize is grown in more countries than any other crop, and is a major source of food for both humans and domesticated animals throughout the world. The world production of maize in 2000 exceeded 23 billion bushels, the largest producer being the United...