Wheat is a

grass Poaceae () or Gramineae () is a large and nearly ubiquitous family of monocotyledonous flowering plants commonly known as grasses. It includes the cereal grasses, bamboos and the grasses of natural grassland and species cultivated in lawns an ...

widely cultivated for its

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

, a

cereal A cereal is any Poaceae, grass cultivated for the edible components of its grain (botanically, a type of fruit called a caryopsis), composed of the endosperm, Cereal germ, germ, and bran. Cereal Grain, grain crops are grown in greater quantit ...

grain A grain is a small, hard, dry fruit (caryopsis) – with or without an attached hull layer – harvested for human or animal consumption. A grain crop is a grain-producing plant. The two main types of commercial grain crops are cereals and legum ...

that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is

common wheat 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 ...

(''T. aestivum''). The archaeological record suggests that wheat was first cultivated in the regions of the

Fertile Crescent The Fertile Crescent ( ar, الهلال الخصيب) is a crescent-shaped region in the Middle East, spanning modern-day Iraq, Syria, Lebanon, Israel, Palestine and Jordan, together with the northern region of Kuwait, southeastern region of ...

around 9600 BCE. Botanically, the wheat kernel is a type of fruit called a caryopsis. Wheat is grown on more land area than any other food crop (, 2014). World trade in wheat is greater than for all other crops combined. In 2020, world production of wheat was , making it the second most-produced cereal after

maize Maize ( ; ''Zea mays'' subsp. ''mays'', from es, maíz after tnq, mahiz), also known as corn (North American and Australian English), is a cereal grain first domesticated by indigenous peoples in southern Mexico about 10,000 years ago. Th ...

. Since 1960, world production of wheat and other grain crops has tripled and is expected to grow further through the middle of the 21st century. Global demand for wheat is increasing due to the unique viscoelastic and adhesive properties of gluten proteins, which facilitate the production of processed foods, whose consumption is increasing as a result of the worldwide industrialization process and the westernization of the diet. Wheat is an important source of

carbohydrate In organic chemistry, a carbohydrate () is a biomolecule consisting of carbon (C), hydrogen (H) and oxygen (O) atoms, usually with a hydrogen–oxygen atom ratio of 2:1 (as in water) and thus with the empirical formula (where ''m'' may or ma ...

s. Globally, it is the leading source of

vegetable proteins Vegetables are parts of plants that are consumed by humans or other animals as food. The original meaning is still commonly used and is applied to plants collectively to refer to all edible plant matter, including the flowers, fruits, stems, ...

in human food, having a protein content of about 13%, which is relatively high compared to other major cereals but relatively low in protein quality for supplying essential amino acids. When eaten as the

whole grain A whole grain is a grain of any cereal and pseudocereal that contains the endosperm, germ, and bran, in contrast to refined grains, which retain only the endosperm. As part of a general healthy diet, consumption of whole grains is associated w ...

, wheat is a source of multiple

nutrient A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...

s and

dietary fiber Dietary fiber (in British English fibre) or roughage is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. Dietary fibers are diverse in chemical composition, and can be grouped generally by the ...

. In a small part of the general population, glutenthe major part of wheat proteincan trigger coeliac disease, noncoeliac gluten sensitivity,

gluten ataxia Ataxia is a neurological sign consisting of lack of voluntary Motor coordination, coordination of muscle movements that can include gait abnormality, speech changes, and abnormalities in eye movements. Ataxia is a clinical manifestation indicati ...

, and dermatitis herpetiformis.

Origin and history

Cultivation and repeated harvesting and sowing of the grains of wild grasses led to the creation of domestic strains, as mutant forms ('sports') of wheat were preferentially chosen by farmers. In domesticated wheat, grains are larger, and the seeds (inside the spikelets) remain attached to the ear by a toughened rachis during harvesting. In wild strains, a more fragile rachis allows the ear to easily shatter and disperse the spikelets. Selection for larger grains and non-shattering heads by farmers might not have been deliberately intended, but simply have occurred because these traits made gathering the seeds easier; nevertheless such 'incidental' selection was an important part of crop domestication. As the traits that improve wheat as a food source also involve the loss of the plant's natural seed dispersal mechanisms, highly domesticated strains of wheat cannot survive in the wild. Archaeological analysis of wild emmer indicates that it was first cultivated in the southern

Levant The Levant () is an approximate historical geographical term referring to a large area in the Eastern Mediterranean region of Western Asia. In its narrowest sense, which is in use today in archaeology and other cultural contexts, it is eq ...

, with finds dating back as far as 9600 BC. Genetic analysis of wild ''

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

'' wheat suggests that it was first grown in the Karacadaǧ Mountains in southeastern Turkey. Dated archeological remains of einkorn wheat in settlement sites near this region, including those at

Abu Hureyra Tell Abu Hureyra ( ar, تل أبو هريرة) is a prehistoric archaeological site in the Upper Euphrates valley in Syria. The tell was inhabited between 13,000 and 9,000 years ago in two main phases: Abu Hureyra 1, dated to the Epipalaeolit ...

in Syria, suggest the domestication of einkorn near the Karacadaǧ Mountains. With the anomalous exception of two grains from

Iraq ed-Dubb Iraq ed-Dubb, or the Cave of the Bear, is an early Neolithic archeological site northwest of Ajlun in the Jordan Valley, in modern-day Jordan. The settlement existed before 8,000 BCE and experimented with the cultivation of founder crops, side ...

, the earliest

carbon-14 Carbon-14, C-14, or radiocarbon, is a radioactive isotope of carbon with an atomic nucleus containing 6 protons and 8 neutrons. Its presence in organic materials is the basis of the radiocarbon dating method pioneered by Willard Libby and coll ...

date for einkorn wheat remains at Abu Hureyra is 7800 to 7500 years BC. Remains of harvested emmer from several sites near the Karacadag Range have been dated to between 8600 (at Cayonu) and 8400 BC (Abu Hureyra), that is, in the

Neolithic The Neolithic period, or New Stone Age, is an Old World archaeological period and the final division of the Stone Age. It saw the Neolithic Revolution, a wide-ranging set of developments that appear to have arisen independently in several parts ...

period. With the exception of Iraq ed-Dubb, the earliest carbon-14 dated remains of domesticated emmer wheat were found in the earliest levels of

Tell Aswad Tell Aswad ( ar, تل أسود, "Hill Black"), Su-uk-su or Shuksa, is a large prehistoric, neolithic tell, about in size, located around from Damascus in Syria, on a tributary of the Barada River at the eastern end of the village of Jdeide ...

, in the

Damascus )), is an adjective which means "spacious". , motto = , image_flag = Flag of Damascus.svg , image_seal = Emblem of Damascus.svg , seal_type = Seal , map_caption = , ...

basin, near Mount Hermon in Syria. These remains were dated by

Willem van Zeist Willem van Zeist (March 12, 1924 – October 7, 2016) was a Dutch archaeobotanist and palynologist. He was the director of the ''Biologisch-Archaeologisch Instituut'' at the University of Groningen. Education Van Zeist studied biology at the U ...

and his assistant Johanna Bakker-Heeres to 8800 BC. They also concluded that the settlers of Tell Aswad did not develop this form of emmer themselves, but brought the domesticated grains with them from an as yet unidentified location elsewhere. The cultivation of emmer reached Greece, Cyprus and

Indian subcontinent The Indian subcontinent is a list of the physiographic regions of the world, physiographical region in United Nations geoscheme for Asia#Southern Asia, Southern Asia. It is situated on the Indian Plate, projecting southwards into the Indian O ...

by 6500 BC, Egypt shortly after 6000 BC, and Germany and Spain by 5000 BC. "The early Egyptians were developers of bread and the use of the oven and developed baking into one of the first large-scale food production industries." By 4000 BC, wheat had reached the British Isles and Scandinavia. Wheat likely appeared in China's lower Yellow River around 2600 Before Common Era (BC). The oldest evidence for hexaploid wheat has been confirmed through DNA analysis of wheat seeds, dating to around 6400–6200 BC, recovered from

Çatalhöyük Çatalhöyük (; also ''Çatal Höyük'' and ''Çatal Hüyük''; from Turkish ''çatal'' "fork" + ''höyük'' "tumulus") is a tell of a very large Neolithic and Chalcolithic proto-city settlement in southern Anatolia, which existed from appr ...

. The first identifiable bread wheat (''Triticum aestivum'') with sufficient gluten for yeasted breads has been identified using DNA analysis in samples from a granary dating to approximately 1350 BC at Assiros in Macedonia. From Asia, wheat continued to spread across Europe and to the

Americas The Americas, which are sometimes collectively called America, are a landmass comprising the totality of North and South America. The Americas make up most of the land in Earth's Western Hemisphere and comprise the New World. Along with th ...

in the

Columbian exchange The Columbian exchange, also known as the Columbian interchange, was the widespread transfer of plants, animals, precious metals, commodities, culture, human populations, technology, diseases, and ideas between the New World (the Americas) in ...

. In the British Isles, wheat straw (thatch) was used for roofing in the Bronze Age, and was in common use until the late 19th century. White wheat bread was historically a high status food, but during the nineteenth century it became in Britain an item of mass consumption, displacing oats, barley and rye from diets in the North of the country. It became "a sign of a high degree of culture". After 1860, the enormous expansion of wheat production in the United States flooded the world market, lowering prices by 40%, and (along with the expansion of potato growing) made a major contribution to the nutritional welfare of the poor.

Farming techniques

Technological advances in soil preparation and seed placement at planting time, use of

crop rotation Crop rotation is the practice of growing a series of different types of crops in the same area across a sequence of growing seasons. It reduces reliance on one set of nutrients, pest and weed pressure, and the probability of developing resistant ...

and

fertilizer A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...

s to improve plant growth, and advances in harvesting methods have all combined to promote wheat as a viable crop. When the use of seed drills replaced broadcasting sowing of seed in the 18th century, another great increase in productivity occurred. Yields of pure wheat per unit area increased as methods of crop rotation were applied to long cultivated land, and the use of fertilizers became widespread. Improved agricultural husbandry has more recently included threshing machines,

reaper-binder The reaper-binder, or binder, is a farm implement that improved upon the simple reaper. The binder was invented in 1872 by Charles Baxter Withington, a jeweler from Janesville, Wisconsin. In addition to cutting the small-grain crop, a binder also ...

machines (the '

combine harvester The modern combine harvester, or simply combine, is a versatile machine designed to efficiently harvest a variety of grain crops. The name derives from its combining four separate harvesting operations—reaping, threshing, gathering, and winnow ...

'),

tractor A tractor is an engineering vehicle specifically designed to deliver a high tractive effort (or torque) at slow speeds, for the purposes of hauling a trailer or machinery such as that used in agriculture, mining or construction. Most common ...

-drawn cultivators and planters, and better varieties (see Green Revolution and Norin 10 wheat). Great expansion of wheat production occurred as new arable land was farmed in the Americas and Australia in the 19th and 20th centuries. File:Green wheat.jpg, Green wheat a month before harvest File:Young Wheat crop in a field near Solapur, Maharashtra, India.jpg, Young wheat crop in a field near Solapur,

Maharashtra, India Maharashtra (; , abbr. MH or Maha) is a state in the western peninsular region of India occupying a substantial portion of the Deccan Plateau. Maharashtra is the second-most populous state in India and the second-most populous country subdivi ...

File:Melissa Askew 2015-08-08 (Unsplash).jpg, Wheat crop near Solapur, India File:Wheat Farm in Behbahan, Iran.jpg, alt=Wheat Farm in Behbahan, Iran, Wheat farm in Behbahan, Iran File:Unload wheat by the combine Claas Lexion 584.jpg, A

threshes the wheat, crushes the

chaff Chaff (; ) is the dry, scaly protective casing of the seeds of cereal grains or similar fine, dry, scaly plant material (such as scaly parts of flowers or finely chopped straw). Chaff is indigestible by humans, but livestock can eat it. In agri ...

, then blows chaff across the field. The combine loads the threshed wheat onto a truck or trailer while moving File:Sealed_storage_method_for_wheat.jpg, Two tractors deploying a sealed storage method for newly harvested wheat. File:Geography of Ohio - DPLA - aaba7b3295ff6973b6fd1e23e33cde14 (page 49) (cropped).jpg, Map depicting acreage devoted to wheat in Ohio, 1923 Wheatfield near Weethalle IMG 20211115 164812.jpg, Wheatfield near Weethalle, NSW

Physiology

Leaves emerge from the shoot apical meristem in a telescoping fashion until the transition to reproduction i.e. flowering. The last leaf produced by a wheat plant is known as the flag leaf. It is denser and has a higher

photosynthetic Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that, through cellular respiration, can later be released to fuel the organism's activities. Some of this chemical energy is stored in c ...

rate than other leaves, to supply

to the developing ear. In temperate countries the flag leaf, along with the second and third highest leaf on the plant, supply the majority of carbohydrate in the grain and their condition is paramount to yield formation. Wheat is unusual among plants in having more

stomata In botany, a stoma (from Greek ''στόμα'', "mouth", plural "stomata"), also called a stomate (plural "stomates"), is a pore found in the epidermis of leaves, stems, and other organs, that controls the rate of gas exchange. The pore is bor ...

on the upper (adaxial) side of the leaf, than on the under (abaxial) side. It has been theorised that this might be an effect of it having been domesticated and cultivated longer than any other plant.

Winter wheat Winter wheat (usually ''Triticum aestivum'') are strains of wheat that are planted in the autumn to germinate and develop into young plants that remain in the vegetative phase during the winter and resume growth in early spring. Classification ...

generally produces up to 15 leaves per shoot and spring wheat up to 9 and winter crops may have up to 35 tillers (shoots) per plant (depending on cultivar). Wheat

root In vascular plants, the roots are the organs of a plant that are modified to provide anchorage for the plant and take in water and nutrients into the plant body, which allows plants to grow taller and faster. They are most often below the sur ...

s are among the deepest of arable crops, extending as far down as . While the roots of a wheat plant are growing, the plant also accumulates an energy store in its stem, in the form of

fructans A fructan is a polymer of fructose molecules. Fructans with a short chain length are known as fructooligosaccharides. Fructans can be found in over 12% of the angiosperms including both monocots and dicots such as agave, artichokes, asparagus, leek ...

, which helps the plant to yield under drought and disease pressure, but it has been observed that there is a trade-off between root growth and stem non-structural carbohydrate reserves. Root growth is likely to be prioritised in drought-adapted crops, while stem non-structural carbohydrate is prioritised in varieties developed for countries where disease is a bigger issue. Depending on variety, wheat may be awned or not awned. Producing awns incurs a cost in grain number, but wheat awns photosynthesise more efficiently than their leaves with regards to water usage, so awns are much more frequent in varieties of wheat grown in hot drought-prone countries than those generally seen in temperate countries. For this reason, awned varieties could become more widely grown due to

climate change In common usage, climate change describes global warming—the ongoing increase in global average temperature—and its effects on Earth's climate system. Climate change in a broader sense also includes previous long-term changes to E ...

. In Europe, however, a decline in

climate resilience Climate resilience is defined as the "capacity of social, economic and ecosystems to cope with a hazardous event or trend or disturbance".IPCC, 2022Summary for Policymakers .-O. Pörtner, D.C. Roberts, E.S. Poloczanska, K. Mintenbeck, M. Tignor, ...

of wheat has been observed.

Genetics and breeding

In traditional agricultural systems wheat populations often consist of landraces, informal farmer-maintained populations that often maintain high levels of morphological diversity. Although landraces of wheat are no longer grown in Europe and North America, they continue to be important elsewhere. The origins of formal wheat breeding lie in the nineteenth century, when single line varieties were created through selection of seed from a single plant noted to have desired properties. Modern wheat breeding developed in the first years of the twentieth century and was closely linked to the development of Mendelian genetics. The standard method of breeding inbred wheat cultivars is by crossing two lines using hand emasculation, then selfing or inbreeding the progeny. Selections are ''identified'' (shown to have the genes responsible for the varietal differences) ten or more generations before release as a variety or cultivar. Major breeding objectives include high grain yield, good quality, disease and insect resistance and tolerance to abiotic stresses, including mineral, moisture and heat tolerance. The major diseases in temperate environments include the following, arranged in a rough order of their significance from cooler to warmer climates: eyespot, Stagonospora nodorum blotch (also known as glume blotch),

yellow Yellow is the color between green and orange on the spectrum of light. It is evoked by light with a dominant wavelength of roughly 575585 nm. It is a primary color in subtractive color systems, used in painting or color printing. In the R ...

stripe rust Stripe rust may refer to: * Barley stripe rust * Wheat stripe rust Wheat yellow rust (''Puccinia striiformis'' f.sp. ''tritici''), also known as wheat stripe rust, is one of the three major wheat rust diseases, along with stem rust of wheat ( ...

, powdery mildew,

Septoria tritici ''Zymoseptoria tritici'', synonyms ''Septoria tritici'', ''Mycosphaerella graminicola'', is a species of filamentous fungus, an ascomycete in the family ''Mycosphaerellaceae''. It is a wheat plant pathogen causing septoria leaf blotch that is ...

blotch (sometimes known as leaf blotch),

brown Brown is a color. It can be considered a composite color, but it is mainly a darker shade of orange. In the CMYK color model used in printing or painting, brown is usually made by combining the colors orange and black. In the RGB color model used ...

or leaf rust,

Fusarium head blight Fusarium ear blight (FEB) (also called Fusarium head blight, FHB, or scab), is a fungal disease of cereals, including wheat, barley, oats, rye and triticale. FEB is caused by a range of ''Fusarium'' fungi, which infects the heads of the crop, reduc ...

tan spot ''Pyrenophora tritici-repentis'' (teleomorph) and ''Drechslera tritici-repentis'' (anamorph) is a necrotrophic plant pathogen of fungal origin, phylum Ascomycota. The pathogen causes a disease originally named yellow spot but now commonly called ...

and stem rust. In tropical areas, spot blotch (also known as Helminthosporium leaf blight) is also important. Wheat has also been the subject of

mutation breeding Mutation breeding, sometimes referred to as "variation breeding", is the process of exposing seeds to chemicals, radiation, or enzymes in order to generate mutants with desirable traits to be bred with other cultivars. Plants created using mutagene ...

, with the use of gamma, x-rays, ultraviolet light, and sometimes harsh chemicals. The varieties of wheat created through these methods are in the hundreds (going as far back as 1960), more of them being created in higher populated countries such as China. Bread wheat with high grain iron and zinc content has been developed through gamma radiation breeding, and through conventional selection breeding. International wheat breeding is led by

CIMMYT The International Maize and Wheat Improvement Center (known - even in English - by its Spanish acronym CIMMYT for ''Centro Internacional de Mejoramiento de Maíz y Trigo'') is a non-profit research-for-development organization that develops im ...

in Mexico.

ICARDA The International Center for Agricultural Research in the Dry Areas (ICARDA), a member of CGIAR, supported by the CGIAR Fund, is a non-profit agricultural research institute that aims to improve the livelihoods of the resource-poor across the ...

is another major public sector international wheat breeder, but it was forced to relocate from Syria in the Syrian Civil War.

Yields

The presence of certain versions of wheat genes has been important for crop yields. Genes for the 'dwarfing' trait, first used by Japanese wheat breeders to produce short-stalked wheat, have had a huge effect on wheat yields worldwide, and were major factors in the success of the Green Revolution in Mexico and Asia, an initiative led by Norman Borlaug. Dwarfing genes enable the carbon that is fixed in the plant during photosynthesis to be diverted towards seed production, and they also help prevent the problem of lodging. "Lodging" occurs when an ear stalk falls over in the wind and rots on the ground, and heavy nitrogenous fertilization of wheat makes the grass grow taller and become more susceptible to this problem. By 1997, 81% of the developing world's wheat area was planted to semi-dwarf wheats, giving both increased yields and better response to nitrogenous fertilizer. ''T. turgidum'' subsp. ''polonicum'' is known for its longer

glume In botany, a glume is a bract (leaf-like structure) below a spikelet in the inflorescence (flower cluster) of grasses (Poaceae) or the flowers of sedges (Cyperaceae). There are two other types of bracts in the spikelets of grasses: the lemma and ...

s and grains, has been bred into main wheat lines for its grain size effect, and likely has contributed these traits to '' T. petropavlovskyi'' and the Portuguese landrace group " Arrancada".. As with many plants,

MADS-box The MADS box is a conserved sequence motif. The genes which contain this motif are called the MADS-box gene family. The MADS box encodes the DNA-binding MADS domain. The MADS domain binds to DNA sequences of high similarity to the motif CC /Tsub>6G ...

influences flower development, and more specifically, as with other agricultural Poaceae, heavily influences the total weight output at the end of the entire grain growing process. Despite that importance, little research has been done into MADS-box and other such spikelet and flower genetics in wheat specifically. The world record wheat yield is about , reached in New Zealand in 2017. A project in the UK, led by Rothamsted Research has aimed to raise wheat yields in the country to by 2020, but in 2018 the UK record stood at , and the average yield was just .

Disease resistance

Wild grasses in the genus ''Triticum'' and related genera, and grasses such as

rye Rye (''Secale cereale'') is a grass grown extensively as a grain, a cover crop and a forage crop. It is a member of the wheat tribe (Triticeae) and is closely related to both wheat (''Triticum'') and barley (genus ''Hordeum''). Rye grain is u ...

have been a source of many disease-resistance traits for cultivated wheat

breeding Breeding is sexual reproduction that produces offspring, usually animals or plants. It can only occur between a male and a female animal or plant. Breeding may refer to: * Animal husbandry, through selected specimens such as dogs, horses, and rab ...

since the 1930s. Some resistance genes have been identified against ''

Pyrenophora tritici-repentis ''Pyrenophora tritici-repentis'' (teleomorph) and ''Drechslera tritici-repentis'' ( anamorph) is a necrotrophic plant pathogen of fungal origin, phylum Ascomycota. The pathogen causes a disease originally named yellow spot but now commonly cal ...

'', especially races 1 and 5, those most problematic in

Kazakhstan Kazakhstan, officially the Republic of Kazakhstan, is a transcontinental country located mainly in Central Asia and partly in Eastern Europe. It borders Russia to the north and west, China to the east, Kyrgyzstan to the southeast, Uzbeki ...

. Wild relative, ''

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 ...

'' is the source of several genes effective against

TTKSK Ug99 is a lineage of wheat stem rust (''Puccinia graminis'' f. sp. ''tritici''), which is present in wheat fields in several countries in Africa and the Middle East and is predicted to spread rapidly through these regions and possibly further afie ...

/Ug99 - '' Sr33'', '' Sr45'', '' Sr46'', and '' SrTA1662'' - of which ''Sr33'' and ''SrTA1662'' are the work of Olson et al. 2013, and ''Sr45'' and ''Sr46'' are also briefly reviewed therein. *' is an R gene, a dominant negative for partial adult resistance discovered and molecularly characterized by Moore et al. 2015. ''Lr67'' is effective against all races of

leaf A leaf ( : leaves) is any of the principal appendages of a vascular plant stem, usually borne laterally aboveground and specialized for photosynthesis. Leaves are collectively called foliage, as in "autumn foliage", while the leaves, ste ...

stripe Stripe, striped, or stripes may refer to: Decorations * Stripe (pattern), a line or band that differs in colour or tone from an adjacent surface * Racing stripe, a vehicle decoration * Service stripe, a decoration of the U.S. military Entertainme ...

, and

stem Stem or STEM may refer to: Plant structures * Plant stem, a plant's aboveground axis, made of vascular tissue, off which leaves and flowers hang * Stipe (botany), a stalk to support some other structure * Stipe (mycology), the stem of a mushro ...

rusts, and powdery mildew (''Blumeria graminis''). This is produced by a

mutation In biology, a mutation is an alteration in the nucleic acid sequence of the genome of an organism, virus, or extrachromosomal DNA. Viral genomes contain either DNA or RNA. Mutations result from errors during DNA or viral replication, mi ...

of two aminos in what is predicted to be a

hexose transporter Glucose transporters are a wide group of membrane proteins that facilitate the transport of glucose across the plasma membrane, a process known as facilitated diffusion. Because glucose is a vital source of energy for all life, these transporter ...

. The product then heterodimerizes with the susceptible's product, with the downstream result of reducing

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...

uptake. *' is widely deployed in cultivars due to its abnormally broad effectiveness, conferring resistance against leaf- and stripe-rusts, and powdery mildew. Krattinger et al. 2009 finds ''Lr34'' to also be an ABC transporter and conclude that this is the probably means of its effectiveness and the reason that it produces a 'slow rusting'/ adult resistance phenotype. * ' is a widely used powdery mildew resistance

introgressed Introgression, also known as introgressive hybridization, in genetics is the transfer of genetic material from one species into the gene pool of another by the repeated backcrossing of an interspecific hybrid with one of its parent species. Intr ...

from

(''

Secale cereale Rye (''Secale cereale'') is a grass grown extensively as a grain, a cover crop and a forage crop. It is a member of the wheat tribe (Triticeae) and is closely related to both wheat (''Triticum'') and barley (genus ''Hordeum''). Rye grain is u ...

''). It comes from the rye 1R chromosome, a source of many resistances since the 1960s. (FHB, Fusarium ear blight) is also an important breeding target.

Marker-assisted breeding Marker assisted selection or marker aided selection (MAS) is an indirect selection process where a trait of interest is selected based on a marker ( morphological, biochemical or DNA/RNA variation) linked to a trait of interest (e.g. productivi ...

panels involving

kompetitive allele specific PCR Kompetitive allele specific PCR (KASP) is a homogenous, fluorescence-based genotyping variant of polymerase chain reaction. It is based on allele-specific oligo extension and fluorescence resonance energy transfer for signal generation. A singl ...

can be used. Singh et al. 2019 identify a KASP genetic marker for a pore-forming toxin-like gene providing FHB resistance.

Hybrid wheats

Because wheat self-pollinates, creating

hybrid seed In agriculture and gardening, hybrid seed is produced by cross-pollinated plants. Hybrid seed production is predominant in modern agriculture and home gardening. It is one of the main contributors to the dramatic rise in agricultural output during ...

is extremely labor-intensive; the high cost of hybrid wheat seed relative to its moderate benefits have kept farmers from adopting them widely despite nearly 90 years of effort. F1 hybrid wheat cultivars should not be confused with wheat cultivars deriving from standard

plant breeding Plant breeding is the science of changing the traits of plants in order to produce desired characteristics. It has been used to improve the quality of nutrition in products for humans and animals. The goals of plant breeding are to produce cro ...

, which may descend from hybrid crosses further back in its ancestry.

Heterosis Heterosis, hybrid vigor, or outbreeding enhancement is the improved or increased function of any biological quality in a hybrid offspring. An offspring is heterotic if its traits are enhanced as a result of mixing the genetic contributions of ...

or hybrid vigor (as in the familiar F1 hybrids of maize) occurs in common (hexaploid) wheat, but it is difficult to produce seed of hybrid cultivars on a commercial scale as is done with maize because wheat flowers are perfect in the botanical sense, meaning they have both male and female parts, and normally

self-pollinate Self-pollination is a form of pollination in which pollen from the same plant arrives at the stigma of a flower (in flowering plants) or at the ovule (in gymnosperms). There are two types of self-pollination: in autogamy, pollen is transferred t ...

.Bajaj, Y.P.S. (1990) ''Wheat''. Springer. pp. 161–63. . Commercial hybrid wheat seed has been produced using chemical hybridizing agents,

plant growth regulators Plant hormone (or phytohormones) are signal molecules, produced within plants, that occur in extremely low concentrations. Plant hormones control all aspects of plant growth and development, from embryogenesis, the regulation of organ size, pa ...

that selectively interfere with pollen development, or naturally occurring

cytoplasmic male sterility Cytoplasmic male sterility is total or partial male sterility in plants as the result of specific nuclear and mitochondrial interactions. Male sterility is the failure of plants to produce functional anthers, pollen, or male gametes. Background Jo ...

systems. Hybrid wheat has been a limited commercial success in Europe (particularly France), the United States and South Africa. Synthetic hexaploids made by crossing the wild goatgrass wheat ancestor ''

'', and various other ''

Aegilops ''Aegilops'' is a genus of Eurasian and North American plants in the grass family, Poaceae. They are known generally as goatgrasses.

'', and various durum wheats are now being deployed, and these increase the genetic diversity of cultivated wheats.

Triticale: Wheat-rye hybrid

In ancient times, wheat was often considered a luxury grain because it had lower yield but better taste and digestibility than competitors like rye. In the 19th century, efforts were made to hybridize the two to get a crop with the best traits of both. This produced triticale, a grain with high potential, but fraught with problems relating to fertility and germination. These have mostly been solved, so that in the 20th century millions of acres of triticale are being grown worldwide.

Gluten

Modern bread wheat varieties have been

cross-bred A crossbreed is an organism with purebred parents of two different breeds, varieties, or populations. ''Crossbreeding'', sometimes called "designer crossbreeding", is the process of breeding such an organism, While crossbreeding is used to main ...

to contain greater amounts of gluten, which affords significant advantages for improving the quality of breads and pastas from a functional point of view. However, a 2020 study that grew and analyzed 60 wheat cultivars from between 1891 and 2010 found no changes in albumin/globulin and gluten contents over time. "Overall, the harvest year had a more significant effect on protein composition than the cultivar. At the protein level, we found no evidence to support an increased immunostimulatory potential of modern winter wheat."

Water efficiency

Stomata (or leaf pores) are involved in both uptake of carbon dioxide gas from the atmosphere and water vapor losses from the leaf due to water

transpiration Transpiration is the process of water movement through a plant and its evaporation from aerial parts, such as leaves, stems and flowers. Water is necessary for plants but only a small amount of water taken up by the roots is used for growth a ...

. Basic physiological investigation of these gas exchange processes has yielded valuable carbon

isotope Isotopes are two or more types of atoms that have the same atomic number (number of protons in their nuclei) and position in the periodic table (and hence belong to the same chemical element), and that differ in nucleon numbers (mass numbers) ...

based methods that are used for breeding wheat varieties with improved water-use efficiency. These varieties can improve crop productivity in rain-fed dry-land wheat farms.

Insect resistance

The gene ''Sm1'' protects against the orange wheat blossom midge.

Genome

In 2010, a team of UK scientists funded by

BBSRC Biotechnology and Biological Sciences Research Council (BBSRC), part of UK Research and Innovation, is a non-departmental public body (NDPB), and is the largest UK public funder of non-medical bioscience. It predominantly funds scientific rese ...

announced they had decoded the wheat genome for the first time (95% of the genome of a variety of wheat known as Chinese Spring line 42). This genome was released in a basic format for scientists and plant breeders to use but was not a fully annotated sequence which was reported in some of the media. On 29 November 2012, an essentially complete gene set of bread wheat was published. Random shotgun libraries of total DNA and cDNA from the ''T. aestivum'' cv. Chinese Spring (CS42) were sequenced in Roche 454 pyrosequencer using GS FLX Titanium and GS FLX+ platforms to generate 85 Gb of sequence (220 million reads) and identified between 94,000 and 96,000 genes. The implications of the research in cereal genetics and breeding includes the examination of genome variation, analysis of population genetics and evolutionary biology, and further studying epigenetic modifications.http://www.currentscience.ac.in/Volumes/104/03/0286.pdf In 2018 an even more complete ''Chinese Spring'' genome was released by a different team. Then in 2020 some of the same researchers produced 15 genome sequences from various locations and varieties around the world – the most complete and detailed so far – along with examples of their own use of the sequences to localize particular insect and disease resistance factors. The team expects these sequences will be useful in future cultivar breeding. is controlled by R genes which are highly race-specific.

Genetic engineering

CRISPR/Cas9

For decades the primary

genetic modification Genetic engineering, also called genetic modification or genetic manipulation, is the modification and manipulation of an organism's genes using technology. It is a set of technologies used to change the genetic makeup of cells, including t ...

technique has been non-homologous end joining (NHEJ). However, since its introduction, the / tool has been extensively adopted, for example: * To intentionally damage three homologs of '' TaNP1'' (a glucose-methanol-choline oxidoreductase gene) to produce a novel

male sterility Cytoplasmic male sterility is total or partial male sterility in plants as the result of specific nuclear and mitochondrial interactions. Male sterility is the failure of plants to produce functional anthers, pollen, or male gametes. Background Jo ...

trait, by Li et al. 2020 * ''Blumeria graminis'' f.sp. ''tritici'' resistance has been produced by Shan et al. 2013 and Wang et al. 2014 by editing one of the mildew resistance locus o genes (more specifically one of the '' Triticum aestivum MLO (TaMLO)'' genes) * '' Triticum aestivum EDR1 (TaEDR1)'' (the '' EDR1'' gene, which inhibits ''Bmt'' resistance) has been

knocked out A knockout (abbreviated to KO or K.O.) is a fight-ending, winning criterion in several full-contact combat sports, such as boxing, kickboxing, muay thai, mixed martial arts, karate, some forms of taekwondo and other sports involving striking, a ...

by Zhang et al. 2017 to improve that resistance * '' Triticum aestivum HRC (TaHRC)'' has been disabled by Su et al. 2019 thus producing ''Gibberella zeae'' resistance. * '' Triticum aestivum Ms1 (TaMs1)'' has been knocked out by Okada et al. 2019 to produce another novel male sterility * and '' Triticum aestivum acetolactate synthase (TaALS)'' and '' Triticum aestivum acetyl-CoA-carboxylase (TaACC)'' were subjected to base changes by Zhang et al. 2019 (in two publications) to confer

herbicide resistance Herbicides (, ), also commonly known as weedkillers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page fo ...

ALS inhibitor The acetolactate synthase (ALS) enzyme (also known as acetohydroxy acid or acetohydroxyacid synthase, abbr. AHAS) is a protein found in plants and micro-organisms. ALS catalyzes the first step in the synthesis of the branched-chain amino acids ( ...

s and

ACCase inhibitor Phenoxy herbicides (or "phenoxies") are two families of chemicals that have been developed as commercially important herbicides, widely used in agriculture. They share the part structure of phenoxyacetic acid. Auxins The first group to be discove ...

s respectively these examples illustrate the rapid deployment and results that CRISPR/Cas9 has shown in wheat disease resistance improvement.

Varieties

There are around 20 wheat varieties of 7 species grown throughout the world. In Canada different varieties are blended prior to sale. "Identity preserved" wheat that has been stored and transported separately (at extra cost) usually fetches a higher price. Apart from mutant versions of genes selected in antiquity during domestication, there has been more recent deliberate selection of

allele An allele (, ; ; modern formation from Greek ἄλλος ''állos'', "other") is a variation of the same sequence of nucleotides at the same place on a long DNA molecule, as described in leading textbooks on genetics and evolution. ::"The chro ...

s that affect growth characteristics. Some wheat species are

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. Sets of chromosomes refer to the number of maternal and paternal chromosome copies, respectively ...

, with two sets of

chromosome A chromosome is a long DNA molecule with part or all of the genetic material of an organism. In most chromosomes the very long thin DNA fibers are coated with packaging proteins; in eukaryotic cells the most important of these proteins are ...

s, but many are stable polyploids, with four sets of chromosomes ( tetraploid) or six (

hexaploid 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 ...

).Hancock, James F. (2004) ''Plant Evolution and the Origin of Crop Species''. CABI Publishing. .

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

wheat (''T. monococcum'') is diploid (AA, two complements of seven chromosomes, 2n=14). Most tetraploid wheats (e.g. emmer and

durum 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 ...

wheat) are derived from wild emmer, ''T. dicoccoides''. Wild emmer is itself the result of a hybridization between two diploid wild grasses, '' T. urartu'' and a wild goatgrass such as ''Aegilops searsii'' or '' Ae. speltoides''. The unknown grass has never been identified among non-extinct wild grasses, but the closest living relative is ''Aegilops speltoides''. The hybridization that formed wild emmer (AABB) occurred in the wild, long before domestication, and was driven by natural selection. Wheat harvest

Hexaploid wheats evolved in farmers' fields. Either domesticated emmer or durum wheat hybridized with yet another wild diploid grass (''

'') to make the

wheats,

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. No ...

wheat and

bread wheat 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 ...

. These have ''three'' sets of paired chromosomes, three times as many as in diploid wheat. At the point of the end userthe farmer who is sowing and reapingthe exact variety they have in their field is usually not known. The development of genetic assays which can distinguish the small differences between cultivars is allowing that question to be answered field-by-field, for the first time.

Major cultivated species of wheat

Hexaploid species *

Common wheat 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 ...

or bread wheat (''T. aestivum'') – A

species that is the most widely cultivated in the world. *

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. No ...

(''T. spelta'') – Another hexaploid species cultivated in limited quantities. Spelt is sometimes considered a subspecies of the closely related species

(''T. aestivum''), in which case its botanical name is considered to be ''T. aestivum'' ssp. ''spelta''. Tetraploid species *

Durum 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 ...

(''T. durum'') – A tetraploid form of wheat widely used today, and the second most widely cultivated wheat. * Emmer (''T. dicoccum'') – A tetraploid species, cultivated in ancient times but no longer in widespread use. *

Khorasan Khorasan may refer to: * Greater Khorasan, a historical region which lies mostly in modern-day northern/northwestern Afghanistan, northeastern Iran, southern Turkmenistan, Tajikistan, and Uzbekistan * Khorasan Province, a pre-2004 province of Ira ...

(''T. turgidum ssp. turanicum'', also called ''T. turanicum'') is a tetraploid wheat species. It is an ancient grain type; Khorasan refers to a historical region in modern-day Afghanistan and the northeast of Iran. This grain is twice the size of modern-day wheat and is known for its rich nutty flavor. Diploid species *

(''T. monococcum'') – A

species with wild and cultivated variants. Domesticated at the same time as emmer wheat.

Hulled versus free-threshing species

The four wild species of wheat, along with the domesticated varieties

,Potts, D.T. (1996) ''Mesopotamia Civilization: The Material Foundations'' Cornell University Press. p. 62. . emmer and

, have hulls. This more primitive morphology (in evolutionary terms) consists of toughened glumes that tightly enclose the grains, and (in domesticated wheats) a semi-brittle rachis that breaks easily on threshing. The result is that when threshed, the wheat ear breaks up into spikelets. To obtain the grain, further processing, such as milling or pounding, is needed to remove the hulls or husks. Hulled wheats are often stored as spikelets because the toughened glumes give good protection against pests of stored grain. In free-threshing (or naked) forms, such as durum wheat and common wheat, the glumes are fragile and the rachis tough. On threshing, the chaff breaks up, releasing the grains.

Naming

There are many botanical classification systems used for wheat species, discussed in a separate article on

wheat taxonomy During 10,000 years of cultivation, numerous forms of wheat, many of them hybrids, have developed under a combination of artificial and natural selection. This diversity has led to much confusion in the naming of wheats. This article explains how ...

. The name of a wheat species from one information source may not be the name of a wheat species in another. Within a species, wheat cultivars are further classified by wheat breeders and farmers in terms of: * Growing season, such as

winter wheat Winter wheat (usually ''Triticum aestivum'') are strains of wheat that are planted in the autumn to germinate and develop into young plants that remain in the vegetative phase during the winter and resume growth in early spring. Classification ...

vs. spring wheat.Bridgwater, W. & Beatrice Aldrich. (1966) ''The Columbia-Viking Desk Encyclopedia''. Columbia University. p. 1959. *

Protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

content. Bread wheat protein content ranges from 10% in some soft wheats with high starch contents, to 15% in hard wheats. * The quality of the wheat protein gluten. This protein can determine the suitability of a wheat to a particular dish. A strong and elastic gluten present in bread wheats enables

dough Dough is a thick, malleable, sometimes elastic paste made from grains or from leguminous or chestnut crops. Dough is typically made by mixing flour with a small amount of water or other liquid and sometimes includes yeast or other leavening ag ...

to trap carbon dioxide during leavening, but elastic gluten interferes with the rolling of pasta into thin sheets. The gluten protein in durum wheats used for pasta is strong but not elastic. * Grain color (red, white or amber). Many wheat varieties are reddish-brown due to phenolic compounds present in the bran layer which are transformed to pigments by browning enzymes. White wheats have a lower content of phenolics and browning enzymes, and are generally less astringent in taste than red wheats. The yellowish color of durum wheat and

semolina Semolina is coarsely milled durum wheat mainly used in making couscous, and sweet puddings. The term semolina is also used to designate coarse millings of other varieties of wheat, and sometimes other grains (such as rice or corn) as well. Etymo ...

flour made from it is due to a

carotenoid Carotenoids (), also called tetraterpenoids, are yellow, orange, and red organic compound, organic pigments that are produced by plants and algae, as well as several bacteria, and Fungus, fungi. Carotenoids give the characteristic color to pumpki ...

pigment called

lutein Lutein (;"Lutein"

United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...

are: *

– Very hard, translucent, light-colored grain used to make

flour for pasta and

bulghur Bulgur (from tr, bulgur, itself from fa, بلغور, bolġur (bolghur)/balġur (balghur), groats ), also riffoth (from biblical he, ריפות, riffoth) and burghul (from ar, برغل, burġul ), is a cracked wheat dish found ...

; high in protein, specifically, gluten protein. * Hard Red Spring – Hard, brownish, high-

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...

wheat used for bread and hard baked goods. Bread flour and high-gluten flours are commonly made from hard red spring wheat. It is primarily traded on the

Minneapolis Grain Exchange The Minneapolis Grain Exchange (MGEX) is a commodities and futures exchange of grain products. It was formed in 1881 in Minneapolis, Minnesota, United States as a regional cash marketplace to promote fair trade and to prevent trade abuses in whea ...

. * Hard Red Winter – Hard, brownish, mellow high-protein wheat used for bread, hard baked goods and as an adjunct in other flours to increase protein in pastry flour for pie crusts. Some brands of unbleached all-purpose flours are commonly made from hard red winter wheat alone. It is primarily traded on the Kansas City Board of Trade. Many varieties grown from Kansas south are descendant from a variety known as "turkey red", which was brought to Kansas by

Mennonite Mennonites are groups of Anabaptist Christian church communities of denominations. The name is derived from the founder of the movement, Menno Simons (1496–1561) of Friesland. Through his writings about Reformed Christianity during the Radic ...

immigrants from Russia.

Marquis wheat The Marquis bread wheat cultivar was developed by Dominion Agriculturalist Charles Saunders in 1904. It is a cross between Red Fife (male parent) and Hard Red Calcutta (female parent). It was selected for superiority in milling quality for bread ...

was developed to prosper in the shorter growing season in Canada, and is grown as far south as southern Nebraska. * Soft Red Winter – Soft, low-protein wheat used for cakes, pie crusts, biscuits, and muffins. Cake flour, pastry flour, and some

self-rising flour Flour is a powder made by grinding raw grains, roots, beans, nuts, or seeds. Flours are used to make many different foods. Cereal flour, particularly wheat flour, is the main ingredient of bread, which is a staple food for many cult ...

s with baking powder and salt added, for example, are made from soft red winter wheat. It is primarily traded on the

Chicago Board of Trade The Chicago Board of Trade (CBOT), established on April 3, 1848, is one of the world's oldest futures and options exchanges. On July 12, 2007, the CBOT merged with the Chicago Mercantile Exchange (CME) to form CME Group. CBOT and three other excha ...

. * Hard White – Hard, light-colored, opaque, chalky, medium-protein wheat planted in dry, temperate areas. Used for bread and brewing. * Soft White – Soft, light-colored, very low protein wheat grown in temperate moist areas. Used for pie crusts and pastry. Pastry flour, for example, is sometimes made from soft white winter wheat. Red wheats may need bleaching; therefore, white wheats usually command higher prices than red wheats on the commodities market.

As a food

Raw wheat can be ground into

flour Flour is a powder made by grinding raw grains, roots, beans, nuts, or seeds. Flours are used to make many different foods. Cereal flour, particularly wheat flour, is the main ingredient of bread, which is a staple food for many culture ...

or, using hard

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

only, can be ground into

; germinated and dried creating

malt Malt is germinated cereal grain that has been dried in a process known as " malting". The grain is made to germinate by soaking in water and is then halted from germinating further by drying with hot air. Malted grain is used to make beer, wh ...

; crushed or cut into cracked wheat; parboiled (or steamed), dried, crushed and de-branned into bulgur also known as

groats Groats (or in some cases, "berries") are the hulled kernels of various cereal grains, such as oat, wheat, rye, and barley. Groats are whole grains that include the cereal germ and fiber-rich bran portion of the grain, as well as the endosperm ...

. If the raw wheat is broken into parts at the mill, as is usually done, the outer husk or bran can be used in several ways. Wheat is a major ingredient in such foods as

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 ...

porridge Porridge is a food made by heating or boiling ground, crushed or chopped starchy plants, typically grain, in milk or water. It is often cooked or served with added flavourings such as sugar, honey, (dried) fruit or syrup to make a sweet cereal, ...

, crackers,

biscuit A biscuit is a flour-based baked and shaped food product. In most countries biscuits are typically hard, flat, and unleavened. They are usually sweet and may be made with sugar, chocolate, icing, jam, ginger, or cinnamon. They can also be ...

muesli Muesli ( ) is a cold breakfast dish, the primary ingredient of which is rolled oats, which is set to soak overnight and eaten the next morning. Most often, additional ingredients such as grains, nuts, seeds, and fresh or dried fruits, are added, ...

pancake A pancake (or hotcake, griddlecake, or flapjack) is a flat cake, often thin and round, prepared from a Starch, starch-based batter (cooking), batter that may contain eggs, milk and butter and cooked on a hot surface such as a griddle or fryi ...

s, pasta and noodles,

pie A pie is a baked dish which is usually made of a pastry dough casing that contains a filling of various sweet or savoury ingredients. Sweet pies may be filled with fruit (as in an apple pie), nuts ( pecan pie), brown sugar ( sugar pie), swe ...

pastries Pastry is baked food made with a dough of flour, water and shortening (solid fats, including butter or lard) that may be savoury or sweetened. Sweetened pastries are often described as '' bakers' confectionery''. The word "pastries" suggests ma ...

pizza Pizza (, ) is a dish of Italian origin consisting of a usually round, flat base of leavened wheat-based dough topped with tomatoes, cheese, and often various other ingredients (such as various types of sausage, anchovies, mushrooms, onions ...

cake Cake is a flour confection made from flour, sugar, and other ingredients, and is usually baked. In their oldest forms, cakes were modifications of bread, but cakes now cover a wide range of preparations that can be simple or elaborate, ...

cookie A cookie is a baked or cooked snack or dessert that is typically small, flat and sweet. It usually contains flour, sugar, egg, and some type of oil, fat, or butter. It may include other ingredients such as raisins, oats, chocolate chips, n ...

muffin A muffin is an individually portioned baked product, however the term can refer to one of two distinct items: a part-raised flatbread (like a crumpet) that is baked and then cooked on a griddle (typically unsweetened), or an (often sweetened) ...

rolls Roll or Rolls may refer to: Movement about the longitudinal axis * Roll angle (or roll rotation), one of the 3 angular degrees of freedom of any stiff body (for example a vehicle), describing motion about the longitudinal axis ** Roll (aviation), ...

doughnut A doughnut or donut () is a type of food made from leavened fried dough. It is popular in many countries and is prepared in various forms as a sweet snack that can be homemade or purchased in bakeries, supermarkets, food stalls, and franc ...

gravy Gravy is a sauce often made from the juices of meats that run naturally during cooking and often thickened with wheat flour or corn starch for added texture. The gravy may be further coloured and flavoured with gravy salt (a simple mix of salt an ...

, beer,

vodka Vodka ( pl, wódka , russian: водка , sv, vodka ) is a clear distilled alcoholic beverage. Different varieties originated in Poland, Russia, and Sweden. Vodka is composed mainly of water and ethanol but sometimes with traces of impuritie ...

, boza (a

fermented beverage This is a list of fermented foods, which are foods produced or preserved by the action of microorganisms. In this context, fermentation typically refers to the fermentation of sugar to alcohol using yeast, but other fermentation processes involv ...

), and

breakfast cereal Cereal, formally termed breakfast cereal (and further categorized as cold cereal or warm cereal), is a traditional breakfast food made from processed cereal grains. It is traditionally eaten as part of breakfast, or a snack food, primarily in ...

s. In manufacturing wheat products, gluten is valuable to impart viscoelastic functional qualities in

, enabling the preparation of diverse processed foods such as breads, noodles, and pasta that facilitate wheat consumption.

Nutrition

In 100 grams, wheat provides of food energy and is a rich source (20% or more of the Daily Value, DV) of multiple

essential nutrient A nutrient is a substance used by an organism to survive, grow, and reproduce. The requirement for dietary nutrient intake applies to animals, plants, fungi, and protists. Nutrients can be incorporated into cells for metabolic purposes or excret ...

s, such as

manganese Manganese is a chemical element with the symbol Mn and atomic number 25. It is a hard, brittle, silvery metal, often found in minerals in combination with iron. Manganese is a transition metal with a multifaceted array of industrial alloy use ...

phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...

and

niacin Niacin, also known as nicotinic acid, is an organic compound and a form of vitamin B3, an essential human nutrient. It can be manufactured by plants and animals from the amino acid tryptophan. Niacin is obtained in the diet from a variet ...

(table). Several B vitamins and other dietary minerals are in significant content. Wheat is 13% water, 71%

s, and 1.5% fat. Its 13% protein content is mostly gluten (75–80% of the protein in wheat). Wheat proteins have a low quality for human nutrition, according to the new protein quality method ( DIAAS) promoted by the

Food and Agriculture Organization The Food and Agriculture Organization of the United Nations (FAO)french: link=no, Organisation des Nations unies pour l'alimentation et l'agriculture; it, Organizzazione delle Nazioni Unite per l'Alimentazione e l'Agricoltura is an intern ...

. Though they contain adequate amounts of the other essential amino acids, at least for adults, wheat proteins are deficient in the essential amino acid

lysine Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. It contains an α-amino group (which is in the protonated form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −C ...

. Because the proteins present in the wheat

endosperm The endosperm is a tissue produced inside the seeds of most of the flowering plants following double fertilization. It is triploid (meaning three chromosome sets per nucleus) in most species, which may be auxin-driven. It surrounds the embryo and ...

(gluten proteins) are particularly poor in lysine, white flours are more deficient in lysine compared with whole grains. Significant efforts in plant breeding are being made to develop lysine-rich wheat varieties, without success . Supplementation with proteins from other food sources (mainly

legume A legume () is a plant in the family Fabaceae (or Leguminosae), or the fruit or seed of such a plant. When used as a dry grain, the seed is also called a pulse. Legumes are grown agriculturally, primarily for human consumption, for livestock f ...

s) is commonly used to compensate for this deficiency, since the limitation of a single essential amino acid causes the others to break down and become excreted, which is especially important during the period of growth. of hard red winter wheat contain about 12.6 g of

, 1.5 g of total fat, 71 g of

(by difference), 12.2 g of

, and 3.2 mg of iron (17% of the daily requirement); the same weight of hard red spring wheat contains about 15.4 g of protein, 1.9 g of total fat, 68 g of carbohydrate (by difference), 12.2 g of dietary fiber, and 3.6 mg of iron (20% of the daily requirement).USDA National Nutrient Database for Standard Reference
, Release 25 (2012)

Worldwide production

Wheat is grown on more than . The most common forms of wheat are white and red wheat. However, other natural forms of wheat exist. Other commercially minor but nutritionally promising species of naturally evolved wheat species include black, yellow and blue wheat.

Health effects

Consumed worldwide by billions of people, wheat is a significant food for human nutrition, particularly in the least developed countries where wheat products are primary foods. When eaten as the

, wheat is a healthy food source of multiple nutrients and

recommended for children and adults, in several daily servings containing a variety of foods that meet whole grain-rich criteria. Dietary fiber may also help people feel full and therefore help with a healthy weight. Further, wheat is a major source for natural and biofortified nutrient supplementation, including dietary fiber,

and dietary

minerals In geology and mineralogy, a mineral or mineral species is, broadly speaking, a solid chemical compound with a fairly well-defined chemical composition and a specific crystal structure that occurs naturally in pure form.John P. Rafferty, ed. (2 ...

. Manufacturers of foods containing wheat as a whole grain in specified amounts are allowed a

health claim A health claim on a food label and in food marketing is a claim by a manufacturer of food products that their food will reduce the risk of developing a disease or condition. For example, it is claimed by the manufacturers of oat cereals that oat ...

for marketing purposes in the United States, stating: "low fat diets rich in fiber-containing grain products, fruits, and vegetables may reduce the risk of some types of cancer, a disease associated with many factors" and "diets low in saturated fat and cholesterol and rich in fruits, vegetables, and grain products that contain some types of dietary fiber, particularly

soluble fiber Dietary fiber (in British English fibre) or roughage is the portion of plant-derived food that cannot be completely broken down by human digestive enzymes. Dietary fibers are diverse in chemical composition, and can be grouped generally by the ...

, may reduce the risk of heart disease, a disease associated with many factors". The scientific opinion of the European Food Safety Authority (EFSA) related to health claims on gut health/bowel function, weight control, blood glucose/insulin levels, weight management, blood cholesterol, satiety, glycaemic index, digestive function and cardiovascular health is "that the food constituent, whole grain, (...) is not sufficiently characterised in relation to the claimed health effects" and "that a cause and effect relationship cannot be established between the consumption of whole grain and the claimed effects considered in this opinion."

Concerns

In genetically susceptible people, gluten – a major part of wheat protein – can trigger coeliac disease. Coeliac disease affects about 1% of the general population in

developed countries A developed country (or industrialized country, high-income country, more economically developed country (MEDC), advanced country) is a sovereign state that has a high quality of life, developed economy and advanced technological infrastruct ...

. There is evidence that most cases remain undiagnosed and untreated. The only known effective treatment is a strict lifelong gluten-free diet. While coeliac disease is caused by a reaction to wheat proteins, it is not the same as a

wheat allergy Wheat allergy is an allergy to wheat which typically presents itself as a food allergy, but can also be a contact allergy resulting from occupational exposure. Like all allergies, wheat allergy involves immunoglobulin E and mast cell response. T ...

. Other diseases triggered by eating wheat are non-coeliac gluten sensitivity (estimated to affect 0.5% to 13% of the general population),

, and dermatitis herpetiformis. It has been speculated that

FODMAP FODMAPs or fermentable oligosaccharides, disaccharides, monosaccharides, and polyols are short chain carbohydrates that are poorly absorbed in the small intestine and are prone to absorb water and ferment in the colon. They include short chain o ...

s present in wheat (mainly

fructan A fructan is a polymer of fructose molecules. Fructans with a short chain length are known as fructooligosaccharides. Fructans can be found in over 12% of the angiosperms including both monocots and dicots such as agave, artichokes, asparagus, leek ...

s) are the cause of non-coeliac gluten sensitivity. , reviews have concluded that FODMAPs only explain certain gastrointestinal symptoms, such as bloating, but not the extra-digestive symptoms that people with non-coeliac gluten sensitivity may develop, such as

neurological disorder A neurological disorder is any disorder of the nervous system. Structural, biochemical or electrical abnormalities in the brain, spinal cord or other nerves can result in a range of symptoms. Examples of symptoms include paralysis, muscle weakn ...

fibromyalgia Fibromyalgia (FM) is a medical condition defined by the presence of chronic widespread pain, fatigue, waking unrefreshed, cognitive symptoms, lower abdominal pain or cramps, and depression. Other symptoms include insomnia and a general hyp ...

, psychological disturbances, and

dermatitis Dermatitis is inflammation of the skin, typically characterized by itchiness, redness and a rash. In cases of short duration, there may be small blisters, while in long-term cases the skin may become thickened. The area of skin involved can v ...

. Other proteins present in wheat called amylase-trypsin inhibitors (ATIs) have been identified as the possible activator of the

innate immune system The innate, or nonspecific, immune system is one of the two main immunity strategies (the other being the adaptive immune system) in vertebrates. The innate immune system is an older evolutionary defense strategy, relatively speaking, and is the ...

in coeliac disease and non-coeliac gluten sensitivity. ATIs are part of the plant's natural defense against insects and may cause toll-like receptor 4 ( TLR4)-mediated intestinal

inflammation Inflammation (from la, wikt:en:inflammatio#Latin, inflammatio) is part of the complex biological response of body tissues to harmful stimuli, such as pathogens, damaged cells, or Irritation, irritants, and is a protective response involving im ...

in humans. These TLR4-stimulating activities of ATIs are limited to gluten-containing cereals. A 2017 study in mice demonstrated that ATIs exacerbate preexisting inflammation and might also worsen it at extraintestinal sites. This may explain why there is an increase of inflammation in people with preexisting diseases upon ingestion of ATIs-containing grains.

Comparison with other staple foods

The following table shows the nutrient content of wheat and other major staple foods in a raw form on a dry weight basis to account for their different water contents. Raw forms of these staples, however, are not edible and cannot be digested. These must be sprouted, or prepared and cooked as appropriate for human consumption. In sprouted or cooked form, the relative nutritional and anti-nutritional contents of each of these staples is remarkably different from that of the raw form, as reported in this table. In cooked form, the nutrition value for each staple depends on the cooking method (for example: baking, boiling, steaming, frying, etc.).

Commercial use

Harvested wheat grain that enters trade is classified according to grain properties for the purposes of the commodity- and

international trade International trade is the exchange of capital, goods, and services across international borders or territories because there is a need or want of goods or services. (see: World economy) In most countries, such trade represents a significant ...

markets. Wheat buyers use these to decide which wheat to buy, as each class has special uses, and producers use them to decide which classes of wheat will be most profitable to cultivate. Wheat is widely cultivated as a

cash crop A cash crop or profit crop is an Agriculture, agricultural crop which is grown to sell for profit. It is typically purchased by parties separate from a farm. The term is used to differentiate marketed crops from staple crop (or "subsistence crop") ...

because it produces a good yield per unit area, grows well in a

temperate climate In geography, the temperate climates of Earth occur in the middle latitudes (23.5° to 66.5° N/S of Equator), which span between the tropics and the polar regions of Earth. These zones generally have wider temperature ranges throughout t ...

even with a moderately short

growing season A season is a division of the year marked by changes in weather, ecology, and the amount of daylight. The growing season is that portion of the year in which local conditions (i.e. rainfall, temperature, daylight) permit normal plant growth. Whil ...

, and yields a versatile, high-quality flour that is widely used in

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 " ...

. Most breads are made with wheat flour, including many breads named for the other grains they contain, for example, most

and oat breads. The popularity of foods made from wheat flour creates a large demand for the grain, even in economies with significant food surpluses. In recent years, low international wheat prices have often encouraged farmers in the United States to change to more profitable crops. In 1998, the price at harvest of a bushel was $2.68 per. Some information providers, following CBOT practice, quote the wheat market in per

ton Ton is the name of any one of several units of measure. It has a long history and has acquired several meanings and uses. Mainly it describes units of weight. Confusion can arise because ''ton'' can mean * the long ton, which is 2,240 pounds ...

denomination. A USDA report revealed that in 1998, average operating costs were $1.43 per bushel and total costs were $3.97 per bushel. In that study, farm wheat yields averaged 41.7 bushels per acre (2.2435 metric ton/hectare), and typical total wheat production value was $31,900 per farm, with total farm production value (including other crops) of $173,681 per farm, plus $17,402 in government payments. There were significant profitability differences between low- and high-cost farms, due to crop yield differences, location, and farm size. File:Wheat production, OWID.svg, Annual agricultural production of wheat, measured in tonnes in 2014. File:Wheat yields, OWID.svg, Average wheat yields, measured in tonnes per hectare in 2014.

Production and consumption

In 2020, world wheat production was 761 million tonnes, led by China, India, and Russia collectively providing 38% of the world total. , the largest exporters were Russia (32 million tonnes), United States (27), Canada (23) and France (20), while the largest importers were Indonesia (11 million tonnes), Egypt (10.4) and Turkey (10.0).

Historical factors

British Empire and successor states

Wheat became a central agriculture endeavor in the worldwide

British Empire The British Empire was composed of the dominions, colonies, protectorates, mandates, and other territories ruled or administered by the United Kingdom and its predecessor states. It began with the overseas possessions and trading posts esta ...

in the 19th century, and remains of great importance in Australia, Canada and India. In Australia, with vast lands and a limited work force, expanded production depended on technological advances, especially regarding irrigation and machinery. By the 1840s there were 900 growers in

South Australia South Australia (commonly abbreviated as SA) is a state in the southern central part of Australia. It covers some of the most arid parts of the country. With a total land area of , it is the fourth-largest of Australia's states and territories ...

. They used the "Ridley's Stripper", to remove the heads of grain, and the reaper-harvester perfected by John Ridley in 1843. By 1850 South Australia had become the granary for the region; soon wheat farming spread to Victoria and New South Wales, with heavy exports to Great Britain. In Canada modern farm implements made large scale wheat farming possible from the late 1840s on. By the 1879s Saskatchewan was the center, followed by Alberta, Manitoba and Ontario, as the spread of railway lines allowed easy exports to Britain. By 1910 wheat made up 22% of Canada's exports, rising to 25% in 1930 despite the sharp decline in prices during the worldwide

Great Depression The Great Depression (19291939) was an economic shock that impacted most countries across the world. It was a period of economic depression that became evident after a major fall in stock prices in the United States. The economic contagio ...

. Efforts to expand wheat production in South Africa, Kenya and India were stymied by low yields and disease. However by 2000 India had become the second largest producer of wheat in the world.

United States

In the 19th century the American wheat frontier moved rapidly westward. By the 1880s 70% of American exports went to British ports. The first successful

grain elevator A grain elevator is a facility designed to stockpile or store grain. In the grain trade, the term "grain elevator" also describes a tower containing a bucket elevator or a pneumatic conveyor, which scoops up grain from a lower level and deposits ...

was built in Buffalo in 1842. The cost of transport fell rapidly. In 1869 it cost 37 cents to transport a bushel of wheat from Chicago to Liverpool. In 1905 it was 10 cents.

20th century

In the 20th century, global wheat output expanded by about 5-fold, but until about 1955 most of this reflected increases in wheat crop area, with lesser (about 20%) increases in crop yields per unit area. After 1955 however, there was a ten-fold increase in the rate of wheat yield improvement per year, and this became the major factor allowing global wheat production to increase. Thus technological innovation and scientific crop management with

synthetic nitrogen fertilizer A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...

, irrigation and wheat breeding were the main drivers of wheat output growth in the second half of the century. There were some significant decreases in wheat crop area, for instance in North America. Better seed storage and germination ability (and hence a smaller requirement to retain harvested crop for next year's seed) is another 20th-century technological innovation. In Medieval England, farmers saved one-quarter of their wheat harvest as seed for the next crop, leaving only three-quarters for food and feed consumption. By 1999, the global average seed use of wheat was about 6% of output.

21st century

Several factors are currently slowing the rate of global expansion of wheat production: population growth rates are falling while wheat yields continue to rise. There is evidence, however, that rising temperatures associated with

are reducing wheat yield in several locations. In addition, the better economic profitability of other crops such as soybeans and maize, linked with investment in modern genetic technologies, has promoted shifts to other crops.

Farming systems

In 2014, the most productive

crop yield In agriculture, the yield is a measurement of the amount of a crop grown, or product such as wool, meat or milk produced, per unit area of land. The seed ratio is another way of calculating yields. Innovations, such as the use of fertilizer, the c ...

s for wheat were in Ireland, producing 10 tonnes per hectare. In addition to gaps in farming system technology and knowledge, some large wheat grain-producing countries have significant losses after harvest at the farm and because of poor roads, inadequate storage technologies, inefficient supply chains and farmers' inability to bring the produce into retail markets dominated by small shopkeepers. Various studies in India, for example, have concluded that about 10% of total wheat production is lost at farm level, another 10% is lost because of poor storage and road networks, and additional amounts lost at the retail level. In the

Punjab region Punjab (; Punjabi Language, Punjabi: پنجاب ; ਪੰਜਾਬ ; ; also Romanization, romanised as ''Panjāb'' or ''Panj-Āb'') is a geopolitical, cultural, and historical region in South Asia, specifically in the northern part of the I ...

of the Indian subcontinent, as well as North China, irrigation has been a major contributor to increased grain output. More widely over the last 40 years, a massive increase in fertilizer use together with the increased availability of semi-dwarf varieties in developing countries, has greatly increased yields per hectare. In developing countries, use of (mainly nitrogenous) fertilizer increased 25-fold in this period. However, farming systems rely on much more than fertilizer and breeding to improve productivity. A good illustration of this is Australian wheat growing in the southern winter cropping zone, where, despite low rainfall (300 mm), wheat cropping is successful even with relatively little use of nitrogenous fertilizer. This is achieved by 'rotation cropping' (traditionally called the ley system) with leguminous pastures and, in the last decade, including a canola crop in the rotations has boosted wheat yields by a further 25%. In these low rainfall areas, better use of available soil-water (and better control of soil erosion) is achieved by retaining the stubble after harvesting and by minimizing tillage.

Geographical variation

There are substantial differences in wheat farming, trading, policy, sector growth, and wheat uses in different regions of the world. The largest exporters of wheat in 2016 were, in order of exported quantities: Russian Federation (25.3 million tonnes), United States (24.0 million tonnes), Canada (19.7 million tonnes), France (18.3 million tonnes), and Australia (16.1 million tonnes). The largest importers of wheat in 2016 were, in order of imported quantities: Indonesia (10.5 million tonnes), Egypt (8.7 million tonnes), Algeria (8.2 million tonnes), Italy (7.7 million tonnes) and Spain (7.0 million tonnes). In the rapidly developing countries of Asia and Africa, westernization of diets associated with increasing prosperity is leading to growth in ''per capita'' demand for wheat at the expense of the other food staples.

Most productive

The average annual world farm yield for wheat in 2014 was 3.3 tonnes per hectare (330 grams per square meter). Ireland's wheat farms were the most productive in 2014, with a nationwide average of 10.0 tonnes per hectare, followed by the Netherlands (9.2), and Germany, New Zealand and the United Kingdom (each with 8.6).

Futures contracts

Wheat

futures Futures may mean: Finance *Futures contract, a tradable financial derivatives contract *Futures exchange, a financial market where futures contracts are traded * ''Futures'' (magazine), an American finance magazine Music * ''Futures'' (album), a ...

are traded on the

, Kansas City Board of Trade, and

, and have delivery dates in March (H), May (K), July (N), September (U), and December (Z).

Peak wheat

Agronomy

Crop development

Wheat normally needs between 110 and 130 days between sowing and harvest, depending upon climate, seed type, and soil conditions (

lies dormant during a winter freeze). Optimal crop management requires that the farmer have a detailed understanding of each stage of development in the growing plants. In particular, spring

herbicide Herbicides (, ), also commonly known as weedkillers, are substances used to control undesired plants, also known as weeds.EPA. February 201Pesticides Industry. Sales and Usage 2006 and 2007: Market Estimates. Summary in press releasMain page fo ...

fungicide Fungicides are biocidal chemical compounds or biological organisms used to kill parasitic fungi or their spores. A fungistatic inhibits their growth. Fungi can cause serious damage in agriculture, resulting in critical losses of yield, quality, ...

s, and growth regulators are typically applied only at specific stages of plant development. For example, it is currently recommended that the second application of nitrogen is best done when the ear (not visible at this stage) is about 1 cm in size (Z31 on

Zadoks scale Cereal growth staging scales attempt to objectively measure the growth of cereals. BBCH-scale (cereals) In agronomy, the BBCH-scale for cereals describes the phenological development of cereals using the BBCH-scale. The phenological growth ...

). Knowledge of stages is also important to identify periods of higher risk from the climate. For example, pollen formation from the mother cell, and the stages between

anthesis Anthesis is the period during which a flower is fully open and functional. It may also refer to the onset of that period. The onset of anthesis is spectacular in some species. In ''Banksia'' species, for example, anthesis involves the extension ...

and maturity, are susceptible to high temperatures, and this adverse effect is made worse by water stress. Farmers also benefit from knowing when the 'flag leaf' (last leaf) appears, as this leaf represents about 75% of photosynthesis reactions during the grain filling period, and so should be preserved from disease or insect attacks to ensure a good yield. Several systems exist to identify crop stages, with the Feekes and

s being the most widely used. Each scale is a standard system which describes successive stages reached by the crop during the agricultural season.

Pests and diseases

Pests – or pests and diseases, depending on the definition – consume 21.47% of the world's wheat crop annually.

Diseases

CSIRO ScienceImage 10772 Rustaffected wheat seedlings

There are many wheat diseases, mainly caused by fungi, bacteria, and

viruses A virus is a submicroscopic infectious agent that replicates only inside the living cells of an organism. Viruses infect all life forms, from animals and plants to microorganisms, including bacteria and archaea. Since Dmitri Ivanovsky's 1 ...

Plant breeding Plant breeding is the science of changing the traits of plants in order to produce desired characteristics. It has been used to improve the quality of nutrition in products for humans and animals. The goals of plant breeding are to produce cro ...

to develop new disease-resistant varieties, and sound crop management practices are important for preventing disease. Fungicides, used to prevent the significant crop losses from fungal disease, can be a significant variable cost in wheat production. Estimates of the amount of wheat production lost owing to plant diseases vary between 10 and 25% in Missouri. A wide range of organisms infect wheat, of which the most important are viruses and fungi. The main wheat-disease categories are: * Seed-borne diseases: these include seed-borne scab, seed-borne '' Stagonospora'' (previously known as ''Septoria''), common bunt (stinking smut), and

loose smut Loose smut of barley is caused by ''Ustilago nuda''. It is a disease that can destroy a large proportion of a barley crop. Loose smut replaces grain heads with smut, or masses of spores which infect the open flowers of healthy plants and grow ...

. These are managed with

s. * Leaf- and head-

blight Blight refers to a specific symptom affecting plants in response to infection by a pathogenic organism. Description Blight is a rapid and complete chlorosis, browning, then death of plant tissues such as leaves, branches, twigs, or floral organ ...

diseases: Powdery mildew, leaf rust, ''

'' leaf blotch, ''Stagonospora'' (''Septoria'') nodorum leaf and glume blotch, and ''

Fusarium ''Fusarium'' is a large genus of filamentous fungi, part of a group often referred to as hyphomycetes, widely distributed in soil and associated with plants. Most species are harmless saprobes, and are relatively abundant members of the soil mi ...

'' head scab. * Crown and

root rot Root rot is a condition in which anoxic conditions in the soil or potting media around the roots of a plant cause them to rot. This occurs due to excessive standing water around the roots. It is found in both indoor and outdoor plants, although ...

diseases: Two of the more important of these are ' take-all' and ''

Cephalosporium ''Acremonium'' is a genus of fungi in the family Hypocreaceae. It used to be known as ''Cephalosporium''. Description ''Acremonium'' species are usually slow-growing and are initially compact and moist. Their hyphae are fine and hyaline, and p ...

'' stripe. Both of these diseases are soil borne. * Stem rust diseases: Caused by ''Puccinia graminis'' f. sp. ''tritici'' (basidiomycete) fungi e.g.

Ug99 Ug99 is a lineage of wheat stem rust (''Puccinia graminis'' f. sp. ''tritici''), which is present in wheat fields in several countries in Africa and the Middle East and is predicted to spread rapidly through these regions and possibly further afie ...

* Wheat blast: Caused by ''

Magnaporthe oryzae Triticum ''Magnaporthe'' is a genus of ascomycete fungi. Several of the species are cereal pathogen In biology, a pathogen ( el, πάθος, "suffering", "passion" and , "producer of") in the oldest and broadest sense, is any organism or agent that ca ...

''. * Viral diseases: Wheat spindle streak mosaic (yellow mosaic) and

barley yellow dwarf Barley yellow dwarf (BYD) is a plant disease caused by the ''barley yellow dwarf virus'' (BYDV), and is the most widely distributed viral disease of cereals. It affects the economically important crop species barley, oats, wheat, maize, tritical ...

are the two most common viral diseases. Control can be achieved by using resistant varieties.

Animal pests

Wheat is used as a food plant by the

larva A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle. The ...

e of some

Lepidoptera Lepidoptera ( ) is an order (biology), order of insects that includes butterfly, butterflies and moths (both are called lepidopterans). About 180,000 species of the Lepidoptera are described, in 126 Family (biology), families and 46 Taxonomic r ...

(

butterfly Butterflies are insects in the macrolepidopteran clade Rhopalocera from the Order (biology), order Lepidoptera, which also includes moths. Adult butterflies have large, often brightly coloured wings, and conspicuous, fluttering flight. The ...

and

moth Moths are a paraphyletic group of insects that includes all members of the order Lepidoptera that are not butterflies, with moths making up the vast majority of the order. There are thought to be approximately 160,000 species of moth, many of w ...

) species including the flame,

rustic shoulder-knot ''Apamea sordens'', the rustic shoulder-knot or bordered apamea, is a moth of the family Noctuidae. The species was first described by Johann Siegfried Hufnagel in 1766. It is distributed throughout Europe, east across the Palearctic to Central ...

, setaceous Hebrew character and turnip moth. Early in the season, many species of birds, including the long-tailed widowbird, and rodents feed upon wheat crops. These animals can cause significant damage to a crop by digging up and eating newly planted seeds or young plants. They can also damage the crop late in the season by eating the grain from the mature spike. Recent post-harvest losses in cereals amount to billions of dollars per year in the United States alone, and damage to wheat by various borers, beetles and weevils is no exception. Rodents can also cause major losses during storage, and in major grain growing regions, field mice numbers can sometimes build up explosively to plague proportions because of the ready availability of food. To reduce the amount of wheat lost to post-harvest pests,

Agricultural Research Service The Agricultural Research Service (ARS) is the principal in-house research agency of the United States Department of Agriculture (USDA). ARS is one of four agencies in USDA's Research, Education and Economics mission area. ARS is charged with ext ...

scientists have developed an "insect-o-graph", which can detect insects in wheat that are not visible to the naked eye. The device uses electrical signals to detect the insects as the wheat is being milled. The new technology is so precise that it can detect 5–10 infested seeds out of 30,000 good ones. Tracking insect infestations in stored grain is critical for food safety as well as for the marketing value of the crop.

References

External links

Purdue University Purdue University is a public land-grant research university in West Lafayette, Indiana, and the flagship campus of the Purdue University system. The university was founded in 1869 after Lafayette businessman John Purdue donated land and money ...

{{Authority control Crops Energy crops Poaceae genera Staple foods Taxa named by Carl Linnaeus