Cereal crops are interchangeably called grain crops. In many publications and correspondence, they are simply called grains or cereals. As of 2012, the top 5 cereals in the world ranked on the basis of production tonnage are maize (corn), rice (paddy), wheat, barley and sorghum. These crops are also among the top 50 agricultural commodities in the world with maize ranking second next only to sugarcane, rice (paddy) - 3rd, wheat - 4th, barley - 12th, and sorghum - 30th. Another cereal, millet, ranks no. 42 (FAOStat 2014, updated Aug. 18, 2014).
According to Chapman and Carter (1976), “a cereal is generally
defined as a grass grown for its small, edible seed.” They also
explained that all cereals are angiosperms, monocots, and members of the grass family Gramineae.
Similarly, Lantican (2001) defines cereal or grain crops as agronomic crops belonging to the grass family Gramineae which are utilized as staples; the word “cereal” is derived from the most important grain deity, the Roman Goddess Ceres.
However, it should be clarified that the edible seed of cereals, also referred to as a grain or kernel, is botanically a fruit called caryopsis. It consists of a seed that is enclosed by a pericarp or fruit wall. The pericarp consists of three tissues: the endocarp, the mesocarp, and the exocarp; but these are fused together and inseparable from the seed coat. It is the outermost exocarp that is visible in the kernel of corn (maize).
Cereal crops are necessarily grasses, a composite term which refers to monocot plants under the family Poaceae or Gramineae. They are grown primarily for the harvesting of mature grains or kernels which are used as staple food and animal feed, but also processed into various products such as starch, biofuel (alcohol) and sweetener (i.e., high fructose corn syrup).
Although with similar uses, the pseudocereals or pseudograins are not grasses. They include members of the families Amaranthaceae (amaranths), Chenopodiaceae (goosefoot)and Polygoniaceae (smartweed). The principal pseudograins of the Americas belong to the amaranth and goosefoot families. These plants produce dry fruits which are called by various terms such as nutlets, achenes and grains (http://www.botgard.ucla.edu/html/botanytextbooks/economicbotany/Amaranthus/index.html, accessed October 20, 2010).
FAO's definition of cereals also describes these plants as annual plants (including rice, canary grass, buckwheat and triticale) which generally belong to the gramineous family, producing grains that are used for food, feed, seed and production of industrial products like ethanol. It emphasizes also that the term "cereal crops" should be limited only to those crops that are harvested for dry grain.
It appears, therefore, that in the strict sense cereal crops are grass plants grown for the harvesting of their mature botanical fruits called caryopsis. But the term is now oftenly used to include the pseudocereals (or pseudograins) which are utilized primarily as staple food just like the cereals but they are not grasses.
Further, the harvesting of the thin, outer fruit wall or pericarp only becomes necessary because it is inseparable from the inner seed. It is for the uses of their seeds, particularly the starchy endosperm, that cereal crops are cultivated.
In addition, although cereals are described as annual plants, some can be perennial. Rice and sorghum can be grown as ratoon crops in the tropics. Washington State University (2010) reported that perennial grains can be available in the next two decades. Researches on the development of perennial grains, primarily wheat, are ongoing in several countries.
Click on to read: Production Statistics on Cereals and Other Agri Commodities in the World
Chapman, S.R. and L.P. Carter. 1976. Crop Production: Principles and Practices. San Francisco, USA: W.H. Freeman and Co. pp. 247-258.
FAOSTAT. 2014. Food and agricultural commodities production: commodities by regions. Retrieved Aug. 18, 2014 from http://faostat3.fao.org/faostat-gateway/go/to/browse/rankings/commodities_by_regions/E.
Food and Agriculture Organization
(FA0). 2010. Crops statistics – concepts, definitions and
classifications. Retrieved May 29, 2010 from
http://www.botgard.ucla.edu/html/botanytextbooks/economicbotany/Amaranthus/index.html, accessed October 20, 2010.
Lantican, R.M. 2001. The Science and Practice of Crop Production. UPLB, College, Los Baños, Laguna: SEAMEO SEARCA and UPLB. pp. 4-5
Washington State University. 2010. Agriculture's next revolution- perennial grain- within sight. ScienceDaily. June 27, 2010. Retrieved July 6, 2010 from http://www.sciencedaily.com/releases/2010/06/100624144111.htm.
(Last edited Aug. 18, 2014)