Common wheat (''Triticum aestivum''), also known as bread wheat, is a cultivated

wheat Wheat is a group of wild and crop domestication, domesticated Poaceae, grasses of the genus ''Triticum'' (). They are Agriculture, cultivated for their cereal grains, which are staple foods around the world. Well-known Taxonomy of wheat, whe ...

species. About 95% of wheat produced worldwide is common wheat; it is the most widely grown of all crops and the

cereal A cereal is a grass cultivated for its edible grain. Cereals are the world's largest crops, and are therefore staple foods. They include rice, wheat, rye, oats, barley, millet, and maize ( Corn). Edible grains from other plant families, ...

with the highest monetary yield.

Taxonomy

Numerous forms of wheat have evolved under human selection. This diversity has led to confusion in the naming of wheats, with names based on both genetic and morphological characteristics.

List of common cultivars

* Albimonte * Manital * Shirley * Hilliard

Phylogeny

Bread wheat is an

allohexaploid Polyploidy is a condition in which the cells of an organism have more than two paired sets of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two complete sets of chromosomes, one fro ...

a combination of six sets of chromosomes from different species. Of the six sets of chromosomes, four come from

emmer Emmer is a hybrid species of wheat, producing edible seeds that have been used as food since ancient times. The domesticated types are ''Triticum turgidum'' subsp. ''dicoccum'' and ''T. t. ''conv.'' durum''. The wild plant is called ''T. t.'' s ...

(''Triticum turgidum'', itself a

tetraploid Polyploidy is a condition in which the cells of an organism have more than two paired sets of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two complete sets of chromosomes, one fro ...

) and two from ''

Aegilops tauschii ''Aegilops tauschii'', the Tausch's goatgrass or rough-spike hard grass, is an annual grass species. It is native to Crimea, the Caucasus region, western and Central Asia, Afghanistan, Pakistan, the western Himalaya, and parts of China, and has b ...

'' (a wild

diploid Ploidy () is the number of complete sets of chromosomes in a cell, and hence the number of possible alleles for autosomal and pseudoautosomal genes. Here ''sets of chromosomes'' refers to the number of maternal and paternal chromosome copies, ...

goatgrass). Wild emmer arose from an even earlier ploidy event, a tetraploidy between two diploids, wild

einkorn Einkorn wheat (from German ''Einkorn'', literally "single grain") can refer to either a wild species of wheat (''Triticum'') or a domesticated form of wheat. The wild form is ''T. boeoticum'' (syn. ''T. m.'' subsp. ''boeoticum''), and the domes ...

(''T. urartu'') and '' A. speltoides'' (another wild goatgrass). Free-threshing

is closely related to

spelt Spelt (''Triticum spelta''), also known as dinkel wheat is a species of wheat. It is a relict crop, eaten in Central Europe and northern Spain. It is high in protein and may be considered a health food. Spelt was cultivated from the Neolit ...

. As with spelt, genes contributed from ''Aegilops tauschii'' give bread wheat greater cold hardiness than most wheats, and it is cultivated throughout the world's temperate regions.

Cultivation

History

Common wheat was first domesticated in

West Asia West Asia (also called Western Asia or Southwest Asia) is the westernmost region of Asia. As defined by most academics, UN bodies and other institutions, the subregion consists of Anatolia, the Arabian Peninsula, Iran, Mesopotamia, the Armenian ...

during the early

Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...

, and spread from there to North Africa, Europe and East Asia in the prehistoric period. Naked wheats (including ''Triticum aestivum'', '' T. durum'', and '' T. turgidum'') were found in Roman burial sites ranging from 100 BCE to 300 CE. A field of wheat

Wheat first reached

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

with Spanish missions in the 16th century, but North America's role as a major exporter of grain dates from the colonization of the

prairie Prairies are ecosystems considered part of the temperate grasslands, savannas, and shrublands biome by ecologists, based on similar temperate climates, moderate rainfall, and a composition of grasses, herbs, and shrubs, rather than trees, as the ...

s in the 1870s. As grain exports from Russia ceased during

World War I World War I or the First World War (28 July 1914 – 11 November 1918), also known as the Great War, was a World war, global conflict between two coalitions: the Allies of World War I, Allies (or Entente) and the Central Powers. Fighting to ...

, grain production in

Kansas Kansas ( ) is a landlocked U.S. state, state in the Midwestern United States, Midwestern region of the United States. It borders Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to the west. Kansas is named a ...

doubled. Worldwide, bread wheat has proved well adapted to modern industrial

baking Baking is a method of preparing food that uses dry heat, typically in an oven, but it can also be done in hot ashes, or on hot Baking stone, stones. Bread is the most commonly baked item, but many other types of food can also be baked. Heat is ...

, and has displaced many of the other wheat,

barley Barley (), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains; it was domesticated in the Fertile Crescent around 9000 BC, giving it nonshattering spikele ...

, and

rye Rye (''Secale cereale'') is a grass grown extensively as a grain, a cover crop and a forage crop. It is grown principally in an area from Eastern and Northern Europe into Russia. It is much more tolerant of cold weather and poor soil than o ...

species that were once commonly used for

bread Bread is a baked food product made from water, flour, and often yeast. It is a staple food across the world, particularly in Europe and the Middle East. Throughout recorded history and around the world, it has been an important part of many cu ...

making, particularly in Europe.

Plant breeding

Modern wheat varieties have been selected for short stems, the result of RHt dwarfing genes that reduce the plant's sensitivity to

gibberellic acid Gibberellic acid (also called gibberellin A3 or GA3) is a hormone found in plants and fungi. Its chemical formula is C19H22O6. When purified, it is a white to pale-yellow solid. Plants in their normal state produce large amounts of GA3. It is po ...

, a plant hormone that lengthens cells. RHt genes were introduced to modern wheat varieties in the 1960s by

Norman Borlaug Norman Ernest Borlaug (; March 25, 1914September 12, 2009) was an American agronomist who led initiatives worldwide that contributed to the extensive increases in agricultural production termed the Green Revolution. Borlaug was awarded multiple ...

from Norin 10 cultivars of wheat grown in

Japan Japan is an island country in East Asia. Located in the Pacific Ocean off the northeast coast of the Asia, Asian mainland, it is bordered on the west by the Sea of Japan and extends from the Sea of Okhotsk in the north to the East China Sea ...

. Short stems are important because the application of high levels of chemical fertilizers would otherwise cause the stems to grow too high, resulting in lodging (collapse of the stems). Stem heights are also even, which is important for modern harvesting techniques.

Other forms of common wheat

Compact wheats (e.g., club wheat ''

Triticum compactum ''Triticum compactum'' or club wheat is a species of wheat adapted to low-humidity growing conditions. ''T. compactum'' is similar enough to common wheat (''T. aestivum'') that it is often considered a subspecies, ''T. aestivum compactum''. It c ...

'', but in India ''T. sphaerococcum'') are closely related to common wheat, but have a much more compact ear. Their shorter rachis segments lead to spikelets packed closer together. Compact wheats are often regarded as subspecies rather than species in their own right (thus ''T. aestivum'' subsp. ''compactum'').

References

{{Authority control Wheat cultivars Medicinal plants of Asia Plants described in 1753