WASHINGTON (Reuters) – The history of maize, one of man's indispensable staple crops, is much more complicated than previously known, according to scientists who carried out extensive genetic and archaeological analysis of their domestication.
FILE PHOTO: Corncobs and yellow corn can be seen on a market in Mexico City, Mexico, May 19, 2017. REUTERS / Henry Romero / File Photo
The process of turning the wild predecessor of maize into a vital food source began 9,000 years ago in Mexico, but an early, partially domesticated version was shipped to South America 6,500 years ago, and the crucial further development of the plant was parallel to both places, the researchers said on Thursday.
Until now, it was thought that the domestication process had taken place in the southwestern Balsas River Valley in Mexico, south of Mexico City, and that corn – also called corn – was only later introduced by people elsewhere in North and South America.
The new findings revealed a previously unknown but crucial second phase of domestication in the southwestern Amazon region, which engulfed parts of Brazil and Bolivia, even when domestication was continued in Mexico.
Corn became a worldwide crop after Europeans reached the Americas half a millennium ago. Other crops originating in North and South America are potatoes, sweet potatoes, chocolate, tomatoes, peanuts & avocados.
The researchers analyzed newly sequenced genomes from 40 modern maize varieties and nine archaeological maize samples up to 1,000 years old alongside 68 modern and two old maize taken previously published.
"Quite soon after the initial stages of domestication, people are already moving this new crop over great distances, even before the evolutionary process of domestication has identified all the characteristics that people prefer," said Logan Kistler, curator Archaeogenomics and Archaeobotany at Smithsonian National. natural history museum of the institution in Washington.
The southwestern Amazon region was already a hotspot for the domestication of crops when partially domestic maize was brought there, with squash, yuca and native rice being grown.
Corn's wild predecessor is a grass called teosinte, with negligible flasks and grains protected by a stiff enclosure.
"Corn is one of the most important plant species for humans, we grow it by about a billion tons per year and together with rice and wheat it is one of the most important crops that we rely on for a large part of our calories worldwide," Kistler said. , lead author of the study published in the journal Science.
"Partly because it is such a critically important species for us, the domestication history of corn is one of the kind of fundamental evolutionary events that has greatly shaped the lives and histories of people."
Reporting by Will Dunham; Edited by Sandra Maler