Corn grain bulk load for covered hopper. Corn, also known as Maize, is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. The leafy stalk of the plant produces pollen inflorescences and separate ovuliferous inflorescences called ears that yield kernels or seeds, which are fruits. Corn has become a staple food in many parts of the world, with the total production of corn surpassing that of wheat or rice. However, little of this corn is consumed directly by humans: most is used for corn ethanol, animal feed and other corn products, such as corn starch and corn syrup. The six major types of corn are dent corn, flint corn, pod corn, popcorn, flour corn, and sweet corn. Sugar-rich varieties called sweet corn are usually grown for human consumption as kernels, while field corn varieties are used for animal feed, various corn-based human food uses (including grinding into cornmeal or masa, pressing into corn oil, and fermentation and distillation into alcoholic beverages like bourbon whiskey), and as chemical feedstocks. Corn is also used in making ethanol and other biofuels. Corn is widely cultivated throughout the world, and a greater weight of corn is produced each year than any other grain.