Over the course of thousands of years, American indigenous peoples domesticated, bred and cultivated a large array of plant species. These species still constitute 50–60% of all crops in cultivation worldwide today. The indigenous peoples developed new species and strains through artificial selection. An example is the domestication and breeding of maize from wild teosinte grasses in the valleys of southern Mexico.
The South American highlands were a centre of early agriculture. Genetic testing suggests that the potato has a single origin in the area of southern Peru, from a species in the Solanum brevicaule complex. Over 99% of all modern cultivated potatoes worldwide are descendants of a subspecies indigenous to south-central Chile, Solanum tuberosum ssp. tuberosum, where it was cultivated as long as 10,000 years ago.
Natives of North American began practicing farming approximately 4,000 years ago, that is late in the Archaic period. Pottery was becoming common, and the small-scale felling of trees became feasible. Concurrently, the Archaic Indians began using fire. Intentional burning of vegetation was used to mimic the effects of natural fires that tended to clear forest undergrounds. It made travel easier and facilitated the growth of herbs and berry-producing plants, which were important for both food and medicines.
In the Mississippi River valley, Europeans noted Native Americans’ managed groves of nut and fruit trees as orchards, not far from villages and towns, in addition to their gardens and agricultural fields.
Many crops first domesticated by indigenous Americans are now produced and/or used globally. Chief among these is maize or “corn”, possibly the most important crop in the world. Other significant crops include cassava, chia, squash (pumpkins, zucchini, marrow, acorn squash, butternut squash), the pinto bean, Phaseolus beans including most common beans, tepary beans and lima beans, tomato, potatoes, avocados, peanuts, cocoa beans (used to make chocolate), vanilla, strawberries, pineapples, Peppers (species and varieties of Capsicum, including bell peppers, jalapeños, paprika and chilli peppers) sunflower seeds, rubber, brazil wood, chicle, tobacco, coca, manioc and some species of cotton.