A cereal grass and its edible grain that is used to make rye bread and rye whiskey. Rye cultivation probably originated in southwestern Asia about 6500 BC, migrating westward across the Balkan Peninsula and over Europe. Today rye is grown extensively in Europe, Asia, and North America. It is mainly cultivated where climate and soil are unfavorable for other cereals and as a winter crop where temperatures are too cool for winter wheat. The plant, which thrives in high altitudes, has the greatest winter hardiness of all small grains, growing as far north as the Arctic Circle.