BY PAUL RECER
THE ASSOCIATED PRESS

WASHINGTON -- Ancient farmers in a lost civilization apparently grew cornlike plants on a Mexican coastal plain more than 6,000 years ago. Researchers say traces of pollen from the crude grain may be the earliest evidence of maize farming in North America.
Researchers dug deep pits in fields just off the Gulf of Mexico near San Andres in Mexico and sieved tons of dirt to find traces of an agricultural civilization that spent thousands of years growing crops and cultivating crude grains that later were developed into corn.
"We know nothing about these people, but we know they were growing crops long before people there were thought to be farmers," said John Jones, a Texas A&M researcher and co-author of a study appearing today in the journal Science. "These were hunters and gatherers who also planted crops."
Jones said the scientists found pollen from plants in the botanical family known as Zea that includes teosinte and maize, the ancestors of modern corn.
The researchers found traces of charcoal, such as from domestic fires, but no bones, tools or other clues to the ancient farmers, Jones said.
Zea is thought to have originated in western Mexico, far from the gulf site. Finding the pollen so distant from its native habitat, Jones said, is proof that people transported seed from the west and then planted it when they settled at a site in what is now the Mexican state of Tabasco.
Jones said ancient farmers selectively bred Zea plants over thousands of years until it evolved into the familiar corn, with rows of seeds on a cob. Eventually maize or corn became a common crop throughout the prehistoric Americas.
But when the ancient farmers first were planting it, Jones said, Zea was just a type of grass with large seeds that provided a dependable source of food.
The researchers also found pollen that suggests the ancient farmers may have been the first to domesticate sunflowers as a food crop. The pollen was dated at 4,000 years.
Gayle Fritz, an anthropologist at Washington University in St. Louis, said it is clear that Jones and his group have found the oldest evidence for the cultivation of sunflowers. She is less certain about the conclusions about maize.
"There was a lot of maize grown at that site in later years," she said, noting that is possible that pollen from more recent production was mixed with soil samples from an earlier time. This would distort the dates, Fritz said.