The first domesticated animal in the Americas, as elsewhere in the world, was the dog. It was used for food as well as for work. Other animals included turkeys, and in South America, guinea pigs and llamas. The first domesticated crops depended largely on the region. By far the most important, and among the earliest, domesticated crop was maize, which was first domesticated in Mesoamerica about 5500 years ago. Other domesticated crops in the Americas included the potato, manioc, sunflower, and especially beans, squash, and pumpkins in Mesoamerica and the American Southeast.
Source: Jared Diamond, Guns, Germs, and Steel: The Fates of Human Societies (New York: W.W.Norton and Company, 1999), p. 100.