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

wheat Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeologi ...

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 any grass cultivated for the edible components of its grain (botanically, a type of fruit called a caryopsis), composed of the endosperm, germ, and bran. Cereal grain crops are grown in greater quantities and provide more food ...

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

Phylogeny

Bread wheat is an

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

(an

allopolyploid Polyploidy is a condition in which the cells of an organism have more than one pair of ( homologous) chromosomes. Most species whose cells have nuclei (eukaryotes) are diploid, meaning they have two sets of chromosomes, where each set contains ...

with six sets of chromosomes: two sets from each of three different species). Of the six sets of chromosomes, two come from '' Triticum urartu'' (einkorn wheat) and two from a species related to ''

Aegilops speltoides ''Aegilops speltoides'' ( syn. ''Sitopsis speltoides'' ( Tausch) Á.Löve) is an edible plant in the family Poaceae native to Southeastern Europe and Western Asia, which is often used for animal feed, and it has grown in cultivated beds. This p ...

''. This spontaneous hybridisation created the tetraploid species ''

Triticum turgidum Durum wheat (), also called pasta wheat or macaroni wheat (''Triticum durum'' or ''Triticum turgidum'' subsp. ''durum''), is a tetraploid species of wheat. It is the second most cultivated species of wheat after common wheat, although it represen ...

'' (an ancestor of wild emmer wheat and durum wheat) 580,000–820,000 years ago. The last two sets of chromosomes came from wild goat-grass, '' Aegilops tauschii'', 230,000–430,000 years ago. Recent research suggest that T. macha originated from a hybrid cross between ''

T. aestivum Common wheat (''Triticum aestivum''), also known as bread wheat, is a cultivated wheat species. About 95% of wheat produced worldwide is common wheat; it is the most widely grown of all crops and the cereal with the highest monetary yield. Ta ...

'' and wild emmer wheat. Free-threshing

is closely related to

spelt Spelt (''Triticum spelta''), also known as dinkel wheat or hulled wheat, is a species of wheat that has been cultivated since approximately 5000 BC. Spelt was an important staple food in parts of Europe from the Bronze Age to medieval times. N ...

. 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

Western Asia Western Asia, West Asia, or Southwest Asia, is the westernmost subregion of the larger geographical region of Asia, as defined by some academics, UN bodies and other institutions. It is almost entirely a part of the Middle East, and includes A ...

during the early

Holocene The Holocene ( ) is the current geological epoch. It began approximately 11,650 cal years Before Present (), after the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene togeth ...

, and spread from there to North Africa, Europe and East Asia in the prehistoric period. Naked wheats (including ''Triticum aestivum/durum/turgidum'') were found in Roman burial sites ranging from 100BCE to 300CE . Wheat first reached North America with Spanish missions in the 16th century, but North America's role as a major exporter of grain dates from the colonization of the

prairies 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 t ...

in the 1870s. As grain exports from Russia ceased in the First World War, grain production in

Kansas Kansas () is a U.S. state, state in the Midwestern United States, Midwestern United States. Its Capital city, capital is Topeka, Kansas, Topeka, and its largest city is Wichita, Kansas, Wichita. Kansas is a landlocked state bordered by Nebras ...

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 can also be done in hot ashes, or on hot stones. The most common baked item is bread but many other types of foods can be baked. Heat is gradually transferred " ...

, and has displaced many of the other wheat,

barley Barley (''Hordeum vulgare''), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago. Globally 70% of barley p ...

, and rye species that were once commonly used for

bread Bread is a staple food prepared from a dough of flour (usually wheat) and water, usually by baking. Throughout recorded history and around the world, it has been an important part of many cultures' diet. It is one of the oldest human-made f ...

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, 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 ( ja, 日本, or , and formally , ''Nihonkoku'') is an island country in East Asia. It is situated in the northwest Pacific Ocean, and is bordered on the west by the Sea of Japan, while extending from the Sea of Okhotsk in the n ...

. 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 ...

'', 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