UNIVERSITY PARK, Pa. — Mid-summer corn on the cob is everywhere, but where did it all come from and how did it get to be the big, sweet, yellow ears we eat today? Some of the answers come from carbon dating ancient maize and other organic material from the El Gigante rock shelter in Honduras, according to a team of anthropologists who show that 4,300 years ago maize was sufficiently domesticated to serve as a staple crop in the Honduran highlands.
"Staple crops provide the basis for the development of many complex societies around the world that started developing after about 5,000 years ago," said Douglas J. Kennett, head and professor of anthropology, Penn State. "They are associated with a complete commitment to agriculture."
Maize, or corn in North America, is an important food and fuel crop. The evolutionary history of such a staple is important and archaeological sites with well-preserved maize are incredibly rare, according to Kennett.
The abundance of artifacts and the exceptionally good preservation in the rock shelter that sits on the western escarpment of the Estanzuela River in the highlands of western Honduras make it an ideal site to explore domestication of maize and its transition into a staple crop in the New World. High-precision accelerator mass spectrometry — radiocarbon dating — allowed a precise chronology to be determined for the organic remains found in the rock shelter.
"When you walk across the surface of the rock shelter, the floor is covered with corn cobs and lithics," said Ken Hirth, professor of anthropology, Penn State. "We have about 10,000 pieces of maize plants and 1,000 cobs from the site."
Most researchers agree that maize evolved from the teosinte plant somewhere in the Balsas area of the southwestern region of Mexico and appeared around 9,000 years ago. But the original maize cobs had few rows and kernels.