Washington: Coastal Peruvians munched popcorn a 1,000 years earlier than previously estimated, even before the use of ceramic pottery.

Some of the oldest known corncobs, husks, stalks and tassels, dating from 3,000 to 6,700 years ago were found at Paredones and Huaca Prieta, two mound sites on Peru's arid northern coast.

Characteristics of the cobs, the earliest ever discovered in South America, indicate that the sites' ancient inhabitants ate corn several ways, including popcorn and flour corn.

However, corn was still not an important part of their diet, the journal Proceedings of the National Academy of Sciences reports.

The research group, led by Tom Dillehay from Vanderbilt University and Duccio Bonavia from Peru's Academia Nacional de la Historia, also found corn microfossils: starch grains and phytoliths.

Said Dolores Piperno, curator of New World archaeology at the Smithsonian's National Museum of Natural History who co-authored the report, "Corn was first domesticated in Mexico nearly 9,000 years ago from a wild grass called teosinte."

"Our results show that only a few thousand years later corn arrived in South America where its evolution into different varieties that are now common in the Andean region began," she said, according to a museum statement.

 "This evidence further indicates that in many areas corn arrived before pots did and that early experimentation with corn as a food was not dependent on the presence of pottery," added Piperno.

Corncobs and kernels were not well preserved in the humid tropical forests between Central and South America, including Panama, the primary dispersal routes for the crop after it first left Mexico about 8,000 years ago.

"These new and unique races of corn may have developed quickly in South America, where there was no chance that they would continue to be pollinated by wild teosinte," said Piperno.

(Agencies)