The word cereal derives from Ceres, the name of the pre-Roman goddess of harvest and agriculture. Grains are traditionally called corn in the United Kingdom and Ireland, though that word became specified for maize in the United States, Canada, New Zealand, and Australia.

Production

The following table shows annual production of cereal grains, in 1961, 2005 and 2006, ranked by 2006 production. All but buckwheat and quinoa are true grasses (these two are pseudocereals).

Maize, wheat and rice, between them, accounted for 87% of all grain production, worldwide, and 43% of all food calories in 2003. Other grains that are important in some places, but that have little production globally (and are not included in FAO statistics), include:

• Teff, popular in Ethiopia but scarcely known elsewhere. This ancient grain is a staple in Ethiopia. It is high in fiber and protein. Its flour is often used to make injera. It can also be eaten as a warm breakfast cereal similar to farina with a chocolate or nutty flavor. Its flour and whole grain products can usually be found in natural foods stores.
• Wild rice, grown in small amounts in North America
• Amaranth, ancient pseudocereal, formerly a staple crop of the Aztec Empire (besides maize)
• Kañiwa, close relative of quinoa

Several other species of wheat have also been domesticated, some very early in the history of agriculture:

• Spelt, a close relative of common wheat
• Einkorn, a wheat species with a single grain
• Emmer, one of the first crops domesticated in the Fertile Crescent
• Durum, the only tetraploid species of wheat currently cultivated, used to make semolina

Farming

Barley and rye are the hardiest cereals, able to overwinter in the subarctic and Siberia. Many cool-season cereals are grown in the tropics. However, some are only grown in cooler highlands, where it may be possible to grow multiple crops in a year.

Planting

The warm-season cereals are grown in tropical lowlands year-round and in temperate climates during the frost-free season. Rice is commonly grown in flooded fields, though some strains are grown on dry land. Other warm climate cereals, such as sorghum, are adapted to arid conditions.

Cool-season cereals are well-adapted to temperate climates. Most varieties of a particular species are either winter or spring types. Winter varieties are sown in the autumn, germinate and grow vegetatively, then become dormant during winter. They resume growing in the springtime and mature in late spring or early summer. This cultivation system makes optimal use of water and frees the land for another crop early in the growing season. Winter varieties do not flower until springtime because they require vernalization (exposure to low temperature for a genetically determined length of time). Where winters are too warm for vernalization or exceed the hardiness of the crop (which varies by species and variety), farmers grow spring varieties. Spring cereals are planted in early springtime and mature later that same summer, without vernalization. Spring cereals typically require more irrigation and yield less than winter cereals.