Greenhouse time machine sheds light on corn domestication

By simulating the environment when corn was first exploited by people and then domesticated, Smithsonian scientists discovered that corn's ancestor, a wild grass called teosinte, may have looked very different then than it does today.

The fact that it looks more like corn under these conditions may help to explain how teosinte came to be selected by early farmers who turned it into one of the most important staple crops in the world.

The vegetative and flowering structures of modern teosinte are very different from those of corn. These and other differences led to a century-long dispute as to whether teosinte could really be the ancestor of corn.

"We grew teosinte in the conditions that it encountered 10,000 years ago during the early Holocene period: temperatures 2-3 degrees Celsius cooler than today's with atmospheric carbon dioxide levels at around 260 parts per million," said Dolores Piperno, senior scientist and curator of archaeobotany and South American archaeology at the Smithsonian's National Museum of Natural History and the Smithsonian Tropical Research Institute, who led the project. "Intriguingly, the teosinte plants grown under past conditions exhibit characteristics more like corn: a single main stem topped by a single tassel, a few, very short branches tipped by female ears and synchronous seed maturation.