New Delhi, June 7: Eastern India is part of a swath of territory south of the Himalayas where prehistoric people first cultivated rice, scientists reported on Monday.

Their findings, published in the US journal Proceedings of the National Academy of Sciences, contradict the widely held view that the rice varieties cultivated today originated from wild rice first domesticated in southern China.

The two major rice varieties grown worldwide today ? Oryza sativa indica and Oryza sativa japonica ? owe their origins to two independent events of domestication thousands of years ago, American and Taiwanese researchers said.

In a bid to trace the ancestral roots of rice ? a cereal eaten by more than half of the world’s population ? plant geneticist Barbara Schaal at Washington University and her colleagues analysed the genetic make-up of wild and cultivated rice varieties.

Their studies show that the indica variety was domesticated south of the Himalayas within a region spanning eastern India, Myanmar and Thailand, while the japonica variety was domesticated from wild rice in southern China.

“We now have strong evidence for multiple sites of domestication of rice,” Schaal told The Telegraph over the telephone.

The new studies also suggest that an additional ? third ? domestication event might have occurred in India, giving rise to a minor variety of rice called “aus” ? a drought-tolerant strain cultivated in India and Bangladesh.

As ancient people moved across the continents, they carried rice with them. Rice is now cultivated in every continent except Antarctica.

While there is consensus that rice had its roots in Asia, whether it was domesticated in southern China alone or at multiple locations has been under debate.

The Washington University team is planning studies aimed at narrowing the site of rice domestication within the two broad geographical regions they have identified.

“But it’s unlikely that we’ll be able to pinpoint the site for the first domestication. Humans have been moving rice around throughout history. This shuffling by humans obscures the geographical signals,” Schaal said.