Rice
roots lie in east India
G.S.
MUDUR
http://www.telegraphindia.com/1060608/asp/nation/story_6324661.asp
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.