Grain crops of the world include the food grains, the coarse or feed grains, and a few minor coarse grains. The food grains include rice (Oryza sativa ) and wheat (Triticum aestivum ); the coarse or feed grains are barley (Hordeum vulgare ), maize (Zea mays ), rye (Secale cereale ), oats (Avena sativa ), millets (Pennisetum and Setaria species), sorghum (Sorghum vulgare ), buckwheat (Fagopyrum esculentum ), and triticale X (Triticosecale wittmack ). Except for buckwheat, virtually all of the grain crops are members of the grass family. The principal harvestable commodity of these crops is the grain. Grazing or hay production is a minor use of a few crops.
All of the grain crops now are distributed worldwide, although each crop generally originated in a specific region: rice in Asia; wheat, barley, oats, and rye in the Fertile Crescent of the Mideast; maize in Central America; sorghum and the Pennisetum millets in Africa. Triticale is a human-made grain produced within the twentieth century by hybridizing wheat and rye.
Total production of the two major food grains in 1999 was very similar: 589 Mmt (million metric tons) of rice from 153 Mha (million hectares) and 584 Mmt of wheat from 214 Mha. Much more rice is irrigated than wheat, which results in higher yields and accounts for the essentially equivalent production of rice from fewer hectares than wheat. Coarse grain production in 1999 was 900 Mmt, from 314 Mha. Maize, with 604 Mmt from 139 Mha, was by far the most prominent coarse grain.
Rice is typically consumed as whole grain boiled white rice, while wheat is ground into flour for bread making. Coarse grains are generally fed directly to animals as whole or cracked grains, but small amounts of these crops also are used for food, usually as a ground product or in porridges, especially in the respective regions of origin, for example, maize in Central America, and sorghum and millets in Africa. Barley is used worldwide in brewing, while oats, maize, and wheat are used in many processed cereals. Rye is still used in bread making in Europe and the United States, but food use consumption of this crop declined dramatically fifty years ago when it was recognized that the fungal disease ergot that infects rye grains caused the mysterious malady known as St. Anthony's fire, which can result in convulsions and death.
All of the grain crops are cultivated as annuals: rice, maize, sorghum, and Pennisetum millets as summer crops; while wheat, barley, oats, rye, and Setaria millets are cultivated both as winter crops and as spring crops. The winter versions are grown in mild climates while the spring versions are predominant in the northern regions, such as the former Soviet Union, the northern Great Plains of the United States, and northern China. Winter versions generally yield more than spring versions, because the growing season is much longer for the former.
The Green Revolution refers to the shortening of the stems of rice and wheat, which began in the 1960s and which has often led to doubling of yields. Shorter stemmed versions of the other grain crops have also been produced, especially in sorghum.
see also Agriculture, Modern; Agronomist; Borlaug, Norman; Corn; Economic Importance of Plants; Grasses; Green Revolution; Rice; Seeds; Wheat.
J. Neil Rutger
Food and Agricultural Organization of the United Nations. FAO Statistical Databases. [Online] Available at http://apps.fao.org.
Leonard, Warren H., and John H. Martin. Cereal Crops. New York: Macmillan, 1963.