<P> In Mesoamerica, wild teosinte was transformed through human selection into the ancestor of modern maize, more than 6,000 years ago . It gradually spread across North America and was the major crop of Native Americans at the time of European exploration . Other Mesoamerican crops include hundreds of varieties of locally domesticated squash and beans, while cocoa, also domesticated in the region, was a major crop . The turkey, one of the most important meat birds, was probably domesticated in Mexico or the U.S. Southwest . </P> <P> In Mesoamerica, the Aztecs were active farmers and had an agriculturally focused economy . The land around Lake Texcoco was fertile, but not large enough to produce the amount of food needed for the population of their expanding empire . The Aztecs developed irrigation systems, formed terraced hillsides, fertilized their soil, and developed chinampas or artificial islands, also known as "floating gardens". The Mayas between 400 BC to 900 AD used extensive canal and raised field systems to farm swampland on the Yucatán Peninsula . </P> <P> In the Andes region of South America, with civilizations including the Inca, the major crop was the potato, domesticated approximately 7,000--10,000 years ago . Coca, still a major crop to this day, was domesticated in the Andes, as were the peanut, tomato, tobacco, and pineapple . Cotton was domesticated in Peru by 3,600 BC . Animals were also domesticated, including llamas, alpacas, and guinea pigs . </P> <P> The indigenous people of the Eastern U.S.A. domesticated numerous crops . Sunflowers, tobacco, varieties of squash and Chenopodium, as well as crops no longer grown, including marsh elder and little barley, were domesticated . Wild foods including wild rice and maple sugar were harvested . The most common varieties of strawberry were domesticated from Eastern North America . Two major crops, pecans and Concord grapes, were utilized extensively in prehistoric times but do not appear to have been domesticated until the 19th century . </P>

Where did agriculture develop in the americas about 7000 bp