Transgenic DNA in Mexican Corn Landraces

Background information on Mexican maize

Seed-bearing structure of teosinte, the wild plant from which corn was developed.
Photo: Hugh Iltis

Maize (corn) originated in southern Mexico when early farmers selected variants of the wild plant teosinte that yielded more seeds and produced them in a more easily harvested form. Farmers continued to select early maize for adaptation to different environmental conditions, appearance, and food uses. This process was aided by the natural tendency of corn plants to cross-pollinate with other corn plants, thus shuffling genes and providing more variation from which to select the most desirable plants. The natural genetic diversity of maize in its area of origin, combined with the geographic and ethnic diversity of southern Mexico, has resulted in the development by farmers of many distinct "landraces", native varieties of corn that are adapted to specific areas. Thus, southern Mexico is considered a global center of maize genetic diversity, a potential resource for corn breeders everywhere.

Teosinte growing in Mexico.
Photo copyright Paul Gepts, University of California, Davis

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