Triticum aestivum, common or bread wheat, is an annual grass in the Poaceae (grass family) native to the Mediterranean region and southwest Asia, which is one of several species of cultivated wheat, now grown in temperate climates worldwide. Wheat one of the top two cereal crops grown in the world for human consumption, along with rice (Oryza sativa). (Corn, Zea mays, is grown in larger amounts than either rice or wheat, but a significant portion of it is used for livestock feed and biofuel, rather than human food).
Wheat is one of the most ancient of domesticated crops, with archaeological evidence of the cultivation of various species in the Fertile Crescent dating back to 9,600 BC The various species have been developed into thousands of cultivars (over 25,000, by one estimate) that differ in chromosome number from the primitive diploid types, with 7 pairs of chromosomes, to hybrid allopolyploids, with 14, 21, and 28 chromosome pairs. Cultivars are variously categorized according to their horticultural requirements (spring vs. winter wheat), texture and food uses ( hard wheat, which often contains more gluten and is used for bread; vs. pastry or flour wheat, used for cakes, biscuits, and cookies), or by growth form and seed characteristics (the varieties aestivum, compactum, and spelta are among the six major categories recognized).
Wheat is high in carbohydrates, protein (although it lacks several essential amino acids), and vitamins B and E (if the grain is left whole) is used in countless breads and baked goods, and is an important source of calories for over 1 billion people in the world. Wheat can be refined into starch and wheatgerm oil, and wheat gluten (the proteins that make it sticky) is used in many products. Wheat is also used to make beer and as animal fodder.
The FAO estimates that global commercial production of all types of wheat was 650.9 million metric tons in 2010, harvested from 217.0 million hectares;. It is grown on around 4% of the planet's agricultural land Leading producers were China, India, the US, the Russian Federation, and France. Within the US, the states that were leading producers include Kansas, Montana, North Dakota, South Dakota, Idaho, and Washington.