Spud mystery solved: potato from Peru

WASHINGTON (AFP) - US researchers said that the potato was first cultivated in southern Peru more than 7,000 years ago, citing DNA evidence to resolve a scientific debate about the origins of the ubiquitous vegetable.

A study sponsored by the US Department of Agriculture (USDA) analyzed the DNA of 261 varieties of wild potato and 98 types of cultivated potato to examine whether the "domestic potato" arose from a single source or from multiple sources and geographic areas.

"In contrast to all prior hypotheses of multiple origins of the cultivated potato, we have identified a single origin from a broad area of southern Peru," said David Spooner, a USDA research scientist and professor of horticulture at the University of Wisconsin-Madison who led the study.

The wide distribution of potatoes around the planet across different habitats had supported a hypothesis that potatoes had no single origin.

But the study, published this week in the Proceedings of the National Academies of Sciences, presented DNA data that "in fact all cultivated potatoes can be traced back to a single origin in southern Peru."

Spooner said archaeological evidence indicates that potatoes were first grown by local farmers in Peru "more than 7,000 years ago".

Now some 300 million tonnes of potatoes are produced around the world in a year.

The potato crossed the Atlantic Ocean around 1570 with the Spanish Conquistadors and gradually spread through Europe from Spain. British colonists later introduced the vegetable in North America.

Spooner, who spends about two months a year in the mountains of South America collecting and identifying wild potatoes, said he hoped the study would produce agricultural benefits and shed light on the evolutionary history of crops.

For the study, the professor collaborated with researchers from the Genome Dynamics Program at the Scottish Crop Research Institute in Britain.