teosinte

Teosinte is a group of wild grasses in the genus Zea and the closest living relatives of cultivated maize (Zea mays). The best-known teosinte taxa are Zea mays ssp. parviglumis and Zea mays ssp. mexicana, native to Mexico and parts of Central America. Teosinte plants are typically annual grasses with slender stems, producing small ears composed of a few kernels arranged in rows, each enclosed by tough husks. The kernels shatter at maturity, aiding natural seed dispersal, which contrasts with the non-shattering traits selected in maize.

Domestication and origin: Genetic and archaeological evidence indicates that maize was domesticated from teosinte about 9,000 years ago in the Balsas River region of southwestern Mexico. Through human selection for traits such as larger kernels, fewer ears per plant, and reduced shattering, maize evolved into a highly productive crop. The domestication involved changes in several genes, notably tb1 (teosinte branched1), which alters plant architecture, and tga1 (teosinte glume architecture1), which changes the protective husk around the ears.

Ecology and diversity: Teosinte occupies a range of habitats in Mexico and Central America and is ecologically diverse. It can cross with cultivated maize, a feature exploited in breeding and genetic studies to introduce new diversity and to study domestication. In addition to Zea mays ssp. parviglumis and mexicana, other wild relatives exist, illustrating the evolutionary breadth of the group.

Importance: The teosinte gene pool remains a valuable source of genetic variation for maize improvement, including resistance to pests and abiotic stress. It is central to research on domestication and crop evolution, and conservation of teosinte populations is important for safeguarding genetic resources.