Ancient seeds reveal Andean crops
American and Old World horticulture began about the same time.
Archaeologists have found some of the oldest evidence of cultivated food plants in South America. The squash seeds, peanuts hulls, cotton bolls and quinoa-like seeds add to evidence that the dawn of agriculture in the New World was earlier and more protracted than previously thought.
Tom Dillehay of Vanderbilt University in Nashville, Tennessee, and his colleagues dug beneath floors and peered under ancient grinding-stones in the Peruvian Andes. They found squash seeds around 10,000 years old, a wild peanut far from the region where it typically grows around 8,000 years old, and a cotton boll around 6,000 years old.
"Tom's data adds more evidence that food production — horticulture — developed nearly as early in the Old World as in the New World," says Dolores Piperno, an archaeobotanist at the Smithsonian Tropical Research Institute in Panama. "The evidence has been accumulating for about 15 years." It was once thought that agriculture hit the New World all at once, around 5,000 years ago.
It's unclear how domesticated some of these plants were, even if they had clearly been moved from the wild and grown on purpose. "There is a long period of systematic cultivation before something that we would call domestication appeared," says Piperno.
"In squashes, domestication happened fast," she adds. "Other crops had relatively long periods of pre-domestication cultivation. You can't say that they are wild, you can't say that they are domesticated — they are something in between."
Writing in Science1, Dillehay and his colleagues conclude that squash was domesticated all over Meso-America and South America about 10,000 ago at the beginning of the Holocene, the period with a mild climate and carbon-dioxide rich atmosphere in which we continue to live.
- Dillehay T., et al. Science, 316 . 1890 - 1893 (2007).