History › First civilizations › Agricultural (Neolithic) Revolution
Maize domesticated in Mexico
c. 7000 BC (about 9,000 years ago)· Invention or discovery· Americas & Oceania
Mostly agreedGood evidence; some details, dates or numbers uncertain.
Farmers in southwestern Mexico bred maize (corn) from teosinte, a wild grass, starting about 9,000 years ago.
See it on the History map →What happened
Teosinte, native to the Balsas River valley, has tiny ears with a handful of hard-shelled kernels. Over thousands of years farmers picked plants with bigger ears and softer, more numerous kernels. The oldest known cobs, from Guilá Naquitz cave in Oaxaca, are about 6,250 years old and only about as long as a finger. Grown with beans and squash, the 'three sisters', maize became the staple of Mesoamerica and spread through the Americas.
Why it matters
Maize fed the Olmec, Maya, Aztec and many North American peoples, and after 1492 spread worldwide. It is now the world's largest grain crop by weight.
How we know
Genetic studies tracing maize to Balsas teosinte, starch grains on 8,700-year-old grinding stones at Xihuatoxtla rock shelter in Guerrero, and ancient cobs from Mexican caves.
Still debated
How such an unpromising grass was first chosen, and how fast it changed into productive corn, are still being worked out.
Connections (3)
▸Maize domesticated in Mexico came from an independent center of the Agricultural (Neolithic) RevolutionMostly agreed
The connection
Mesoamerica developed farming entirely separately from the Old World. Squash was domesticated there about 10,000 years ago and maize about 9,000, later joined by beans and chili peppers. Because maize took millennia to become productive, settled farming villages appeared later than in the Middle East, by about 2000–1500 BC.
When and how
Southwestern Mexico, in the Balsas River valley and Oaxaca, from about 8000–7000 BC.
How sure are we?
Ancient squash seeds and maize cobs from Guilá Naquitz cave, starch grains on grinding stones, and genetics tracing maize to local teosinte.
Debates and open questions
Why Mesoamericans grew crops for thousands of years while still living largely as mobile foragers is still discussed.
▸Maize domesticated in Mexico fed Olmec civilizationWell documented
The connection
Maize (corn), domesticated from a wild grass called teosinte, took thousands of years to grow large cobs. By about 1500 BC, with beans and squash, it could feed settled villages. The Olmec grew it on fertile river floodplains, and its surpluses supported the laborers, craftsmen and rulers who built their ceremonial centers.
When and how
Southern Mexico: maize was domesticated in the Balsas River valley about 7000 BC; the Olmec heartland in Veracruz and Tabasco flourished from about 1200 BC.
How we know
Maize pollen, cobs and starch grains in Olmec-area sediments; chemical traces in human bones showing maize-rich diets; Olmec carvings of a maize god.
Debates and open questions
How much the earliest Olmec relied on maize versus fish, root crops and wild foods is debated; maize's share of the diet seems to have grown over time.
▸Maize domesticated in Mexico spread worldwide in the Columbian ExchangeWell documented
The connection
Maize, bred from a wild grass called teosinte in southern Mexico, already fed much of the Americas by 1492. Columbus brought it to Spain in 1493; within a century it grew in Africa, Ottoman lands, India and China. High-yielding and tolerant of poor soils, it became a staple across much of Africa and a major crop in China.
When and how
Spain from 1493, then through Portuguese traders to West Africa and Asia during the 1500s; carried by sailors, merchants and farmers.
How we know
Spanish and Portuguese records, Chinese local gazetteers mentioning maize by the mid-1500s, and genetic studies tracing the world's maize varieties back to the Americas.
Debates and open questions
Exactly how maize reached China, by sea through southern ports or overland from India and Burma, and how fast it spread through Africa, are unclear.