CHICAGO -- Mashed, smashed and fried, Americans love potatoes, but only a few varieties are grown in much of North American agriculture. In South America, where potatoes originated, more than 5,000 varieties continue to exist. A Penn State geographer is gathering all the information he can about the agrobiodiversity of these uniquely adapted tubers with an eye toward sustainability of this fourth largest food crop worldwide.
"In the U.S. we rely primarily on 10 to 12 types of potatoes total," said Karl Zimmerer, department head and professor of geography. "In fact, mostly we use only 5 to 8 varieties. In South America, by contrast, there are 74 different types of potatoes in a single field. The fields, tubers and landscapes are visually stunning."
Zimmerer has studied high-agrobiodiversity land use for over 20 years, but until recently, those studies have been on the ground. He first looked at diversity within individual potato fields and then scaled up to individual communities and landscapes. People in a community have expert knowledge of 150 to 180 varieties of potato, he said.
"People in Peru, for example, love to eat potatoes and think that theirs are vastly superior to what we have in flavor, texture, starchiness and color," said Zimmerer. "They want to hang on to their high-agrobiodiversity potatoes and we want them to hang due to nutritional, ecological and other conservation advantages."
Scaling up even more, Zimmerer looked at potato fields on the landscape level -- typically groups of 5 to 15 communities -- and regions that contain upward of 30 or 40 communities. Remote sensing approaches made this easier, but still only supplied part of the answers to identifying agrobiodiversity hotspots -- biologically rich but environmentally and socioeconomically threatened areas -- and creating ways to protect these areas and conserve these crops. Because the major potato growing area encompasses large parts of northern South America, Zimmerer needed a novel approach, which he presented today (Feb. 15) at the annual meeting of the American Association for the Advancement of Science in Chicago, where he organized a symposium on new agrobiodiversity discoveries needed for sustainability.