What is the difference between a Kumara and a Batata? Very little apparently - they are the Maori and Spanish names, respectively, for the sweet potato. It has been a long held belief that the sweet potato was first introduced to Southeast Asia by Spanish and Portuguese explorers, sometime in the 16th Century, but a gathering accumulation of evidence is pointing to a much older and more interesting explanation.
     A team of researchers from the French Centre of Evolutionary and Functional Ecology has been working closely with a French agricultural research and development centre on the sweet potato genome, and has found it to be extremely complex. By using a temporal control from samples taken by early European explorers, prior to the establishment of the Spanish and Portuguese trade routes, comparisons have been made with native South American sweet potatoes, which have been known to have existed in the high areas of Peru over 8,000 years. They have proved that the first trade between these geographic areas occurred in approximately 1,000 CE, with a second wave by the Spanish over 500-600 years later, closely followed by a third wave by the Portuguese, but moving East from the Caribbean.  
     The research team have placed this new evidence alongside existing information to strengthen, but not yet prove, the case for early trans-Pacific Polynesian traders.

Edited from Science Magazine (21 January 2013)