Wheat

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Wheat, common name for cereal grasses of a genus of the grass family, cultivated for food since prehistoric times by the peoples of the temperate zones and now the most important grain crop of those regions (see Agriculture).

Wheat is a tall, annual plant attaining an average height of 1.2 m (4 ft). The leaves, which resemble those of other grasses, appear early and are followed by slender stalks terminating in spikes, or so-called ears, of grain.

CLASSIFICATION

Species of wheat are classified according to the number of chromosomes found in the vegetative cell. They are divided into three series: the diploid, or einkorn, containing 14 chromosomes; the tetraploid, or emmer, containing 28 chromosomes; and the hexaploid, containing 42 chromosomes. Wheat species crossbreed relatively frequently in nature. Selection of the best varieties for domestication took place over many centuries in many regions.

VARIETIES

According to the regions in which they are grown, certain types of wheat are chosen for their adaptability to altitude, climate, and yield. The common wheats grown in the former Soviet republics, the United States, and Canada are spring and winter wheats, planted either in the spring for summer harvest or in the fall for spring harvest. The color of the grain varies from one type to another; white wheats are mostly winter wheats, red are spring wheats. Closely related to the common wheats are the club wheats, which have especially compact spikes, and spelta (not grown in the United States), in which the glumes (reduced, scalelike leaves) tightly enclose the grains. Durum wheat (Latin durum, “hard”) is so called because of the hardness of the grain. It is grown in north-central regions of the United States. New high-yielding wheats were developed in the 1960s for use in developing countries, and research on them continued in the 1970s. Experimental programs have produced commercial wheat varieties for hardiness and disease resistance. In 1978 the identification of a drought-resistant, high-protein, ancestral species growing in the Middle East held promise of still more improved wheat varieties.

USES

The main use of wheat is in the manufacture of flour for bread and pastries. In general, hard varieties are used for bread flour and soft varieties for pastry flour. Wheat is used also in the production of breakfast foods and to a limited extent in the making of beer, whiskey, and industrial alcohol. Low grades of wheat, and by-products of the flour-milling, brewing, and distilling industries, are used as feed for livestock. A minor amount of wheat is used as a coffee substitute, especially in Europe, and wheat starch is employed as a sizing for textile fabrics.

Scientific classification: Wheat is a member of the family Poaceae (formerly Gramineae). It makes up the genus Triticum.

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