Transcribed from the Columbus Dispatch(OH) of October 14, 2008: "The production of cocoa, chocolate and related products is a huge worldwide industry dependent on the health of the cacao tree, Theobroma cacao. For decades, scientists have thought populations could be classified into one of three genetic groups, but a new study in the online, open-access journal PLoS ONE changes this thinking. A team led by Juan C. Motomayor of the candymaker Mars and the U.S. Department of Agriculture looked at genetic markers in more than 1,200 cacao samples representing world regions, and discovered that there are 10 genetic clusters, not three. The findings suggest that the diversification of cacao occurred in the Amazon as populations became separated by ancient ridges called paleoarches. The new classification will help in managing cacao cultivation and fighting diseases that can harm the trees."
That's totally in line with what I see for differences between the cacao trees in various regions of the Ecuadorian Amazon. Some areas have totally disease-resistant plants, and just 5 or 6 km downriver the trees are getting eaten alive. Neat.