Bread wheat
Family Gramineae (or Poaceae)
Triticum aestivum (= T. sativum, = T. vulgare), wheat (T. aestivum 1), is the major grain used for human consumption in the temperate regions. It is an annual grass, 30-80 cm tall, with erect stems and narrow leaves, up to 40 cm long, acuminate and about 1 cm wide. The inflorescence is a terminal cylindrical spike, 5-10 cm long (T. aestivum 2), with two rows of lateral spikelets, bearded or beardless (T. aestivum 3). Spikelets with 2-5 florets. Grains with central groove, containing 70% starch, 14% protein, 2% fat, and a fair amount of vitamins of the B complex. There are awned and awnless forms, wheats with grains in different colours; hard wheats with grains rich in proteins, and soft wheats which are richer in starch. Soft wheat is grown in Northwest Europe (T. aestivum 4). It has large grains, which are rich in starch, but poor in gluten. The flour is used mainly in pastry and porridge. Hard wheat is the principal wheat in northern America. Because of its high gluten content, it is important for making bread. Without gluten only unleavened bread can be prepared (T. aestivum 11). Another distinction is in spring wheat, sawn in spring and harvested in late summer; and winter wheat, sawn in autumn and harvested in early summer.
Distribution
Wheat is one of the oldest cultivated crops. Archaeological remains of wheat in Mesopotamia date back as far as 5700 BC. It appears in Europe from about 3000 BC. In China it is also known since ancient times. Columbus took wheat to the West Indies in 1493, but it did not survive the climate. Its introduction by the Spaniards to Mexico in 1529 was more successful. It reached Virginia in 1611, California in 1769 and Minnesota in 1845. Nowadays it has spread widely throughout all temperate regions and at the higher altitudes in the tropics.
Use
Wheats are the source of the best bread flours. The flour forms a dough when mixed with water, and due to the gluten that holds the carbon-dioxide produced by the fermenting yeast, it produces a porous bread after leavening and baking. Macaroni, spaghetti, vermicelli and noodles are made from a related species: Triticum durum, see ‘Related taxa’. White flour is produced by removing the pericarp and embryo during milling, in whole flour only part of those are removed. Wheat is also used for the production of alcoholic beverages and industrial alcohol. From the embryos vitamin E is produced. The straw (T. aestivum 5), (T. aestivum 6), (T. aestivum 7) is used as a fodder and for the manufacture of carton.
Yields vary enormously, due to the method of cultivation (T. aestivum 8), (T. aestivum 9), (T. aestivum 10). The world average is about 1900 kg per hectare annually. Biggest producers are India and the US.