Domestication of Teosinte into Maize

In the Central Balsas River Valley of present-day Guerrero, Mexico, early cultivators began selectively breeding the wild grass Zea mays ssp. parviglumis (teosinte) into domesticated maize. Archaeological evidence from the Xihuatoxtla Shelter, excavated by Dolores Piperno and Anthony Ranere, yielded starch grains and phytoliths on grinding stones radiocarbon dated to 8,700 years before present. This region's teosinte populations show the highest genetic diversity among wild relatives, consistent with it being the center of origin.