Tiny amounts of ‘mashed potato’ dating back about 10,900 years have been discovered in Utah.The “well-preserved starch granules” – discovered in cracks in rocks used to grind up the potatoes – are the oldest evidence of cultivation of the plant in North America, researchers said.This technique has been used to find the earliest known use of several species, including oats found in southern Italy dating to 32,600 years ago, 23,000-year-old barley and wheat discovered in Israel, and beans and yams from China dated to between 19,500 and 23,000 years ago.Read moreThe potato starch was embedded into stone tools found in…