US researchers said that the potato was first cultivated in southern Peru more than 7000 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) analysed 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 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".
     Potatoes are a major food staple around the world and mostly belong to a single species, Solanum tuberosum. Potatoes were brought back to Spain by the conquistadors around 1570, and spread throughout Europe. They were later introduced in North America by British colonists.
     Baking potatoes, red potatoes, golden potatoes and other favorites all originated in southern Chile, neighboring Peru, Spooner said. The Chilean potato that gave rise to modern potatoes is probably a hybrid of the ancestral Peruvian potato and a wild species found in Bolivia and Argentina, Spooner added.
     Spooner’s study has helped to rewrite a small but important chapter of evolutionary history. "Books are written about questions of how crops originate. Sometimes statements are repeated so often that they are accepted as fact. This is a way to get people to reconsider long-held assumptions of the origin of the potato, and stimulate us to reconsider the origins of other crops using new methods,” he said.

Sources: Reuters (3 October 2005), BBC News, news24.com, New Kerala (4 October 2005)