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{{Taxobox | color = lightgreen | name = Wheat | image = Koeh-274.jpg | image_width = 250px | regnum = [[Plantae]] | divisio = [[Flowering plant|Magnoliophyta]] | classis = [[Liliopsida]] | ordo = [[Poales]] | familia = [[Poaceae]] | subfamilia = [[Pooideae]] | tribus = [[Triticeae]] | genus = '''''Triticum''''' | genus_authority = [[Carolus Linnaeus|L.]] | subdivision_ranks = Species | subdivision = ''[[Common wheat|T. aestivum]]''<br /> ''T. aethiopicum''<br /> ''T. araraticum''<br /> ''[[einkorn wheat|T. boeoticum]]''<br /> ''T. carthlicum''<br /> ''[[Common is wheat|T. compactum]]''<br /> ''[[Emmer|T. dicoccoides]]''<br /> ''[[Emmer|T. dicoccon]]''<br /> ''[[durum|T. durum]]''<br /> ''T. ispahanicum''<br /> ''T. karamyschevii''<br /> ''T. macha''<br /> ''T. militinae''<br /> ''[[Einkorn|T. monococcum]]''<br /> ''T. polonicum''<br /> ''[[Spelt|T. spelta]]''<br /> ''[[common wheat|T. sphaerococcum]]''<br /> ''[[Triticum timopheevii|T. timopheevii]]''<br /> ''T. turanicum''<br /> ''T. turgidum''<br /> ''T. urartu''<br /> ''T. vavilovii''<br /> ''T. zhukovskyi''<br /> <small>References:<br />&nbsp;&nbsp;[http://www.itis.usda.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=42236 ITIS 42236] 2002-09-22</small> }} [[Image:WheatPennsylvania1943.jpg|thumb|right|Wheat]] [[Image:Wheat P1210892.jpg|thumb|right|Wheat]] {{dablink|For the indie rock group see: [[Wheat (band)]].}} '''Wheat''' (''Triticum'' spp.)<ref name=Belderok>Belderok, Bob & Hans Mesdag & Dingena A. Donner. (2000) ''Bread-Making Quality of Wheat''. Springer. p.3. ISBN 0-7923-6383-3.</ref> is a [[Poaceae|grass]] that is cultivated worldwide. Globally, it is the most important human food grain and ranks second in total production as a [[cereal|cereal crop]] behind [[maize]]; the third being [[rice]].<ref>FAOSTAT database of World Agriculture, 2006</ref> Wheat [[Caryopsis|grain]] is a [[staple food]] used to make [[flour]] for leavened, flat and steamed [[bread]]s; [[cookie]]s, [[cake]]s, [[pasta]], [[noodles]] and [[couscous]];<ref>Cauvain, Stanley P. & Cauvain P. Cauvain. (2003) ''Bread Making''. CRC Press. p. 540. ISBN 1-85573-553-9.</ref> and for [[fermentation (food)|fermentation]] to make [[beer]],<ref>Palmer, John J. (2001) ''How to Brew''. Defenestrative Pub Co. p. 233. ISBN 0-9710579-0-7.</ref> [[alcohol]], [[vodka]]<ref>Neill, Richard. (2002) ''Booze: The Drinks Bible for the 21st Century''. Octopus Publishing Group - Cassell Illustrated. p. 112. ISBN 1-84188-196-1.</ref> or [[biofuel]].<ref>''Department of Agriculture Appropriations for 1957: Hearings ... 84th Congress. 2d Session''. ''United States. Congress. House. Appropriations''. 1956. p. 242.</ref> Wheat is planted to a limited extent as a [[forage|forage crop]] for [[livestock]] and the [[straw]] can be used as [[fodder]] for livestock or as a construction material for roofing [[thatch]].<ref>Smith, Albert E. (1995) ''Handbook of Weed Management Systems''. Marcel Dekker. p. 411. ISBN 0-8247-9547-4.</ref><ref name=CVDE>Bridgwater, W. & Beatrice Aldrich. (1966) ''The Columbia-Viking Desk Encyclopedia''. Columbia University. p. 1959.</ref> == History == Wheat and [[barley]] were the first cereals known to have been domesticated. Wheat originated in [[Southwest Asia]] in the area known as the [[Fertile crescent|Fertile Crescent]]. The genetic relationships between [[einkorn]] and [[emmer]] indicate that the most likely site of domestication is near [[Diyarbakir]] in [[Turkey]] <ref>Jorge Dubcovsky and Jan Dvorak, "Genome Plasticity a Key Factor in the Success of Polyploid Wheat Under Domestication", Science 316 [Issue 5853], p. 1862, 29 June 2007 </ref>. These wild wheats were domesticated as part of the [[origins of agriculture]] in the Fertile Crescent. Cultivation and repeated harvesting and sowing of the grains of wild grasses led to the [[domestication]] of wheat through selection of mutant forms with tough ears which remained intact during harvesting, larger grains, and a tendency for the spikelets to stay on the stalk until harvested <ref>"Seeking Agriculture's Ancient Roots", S cience 316 [Issue 5853], p. 1830, 29 June 2007 </ref>. Because of the loss of seed dispersal mechanisms, domesticated wheats have limited capacity to propagate in the wild.<ref name=Smith>Smith, C. Wayne. (1995) ''Crop Production''. John Wiley and Sons. pp. 60-62. ISBN 0-471-07972-3.</ref> The cultivation of wheat began to spread beyond the Fertile Crescent during the [[Neolithic|Neolithic period]]. By 5,000 years ago, wheat had reached [[Ethiopia]], [[India]], [[Ireland]] and [[Spain]]. A millennium later it reached [[China]].<ref name=Smith /> Agricultural cultivation using [[horse collar]] leveraged plows (3000 years ago) increased cereal grain productivity yields, as did the use of [[seed drill]]s which replaced broadcasting sowing of seed in the 18th century. Yields of wheat continued to increase, as new land came under cultivation and with improved agricultural husbandry involving the use of [[fertilizer]]s, threshing machines and reaping machines (the '[[combine harvester]]'), [[tractor]]-drawn cultivators and planters, and better varieties (see [[green revolution]] and [[Norin 10 wheat]]). With population growth rates falling, while yields continue to rise, the acreage devoted to wheat may now begin to decline for the first time in modern [[human history]].<ref>The Economist, 2005</ref> But now in 2007 wheat stocks have reached their lowest since 1981 and 2006 was the first year in which the world consumed more wheat than the world produced - a gap that is continuously widening as the requirement for wheat increases beyond production. The use of wheat as a bio-fuel will exacerbate the situation. == Genetics == Wheat genetics is more complicated than that of most other domesticated species. Some wheat species are [[diploid]], with two sets of chromosomes, but many are stable [[polyploidy|polyploids]], with four sets of chromosomes ([[tetraploid]]) or six ([[hexaploid]]).<ref name=Hancock>Hancock, James F. (2004) ''Plant Evolution and the Origin of Crop Species''. CABI Publishing. ISBN 0-85199-685-X.</ref> * [[Einkorn]] wheat (''T. monococcum'') is diploid.<ref name=Belderok /> * Most tetraploid wheats (e.g. [[emmer]] and [[durum|durum wheat]]) are derived from wild emmer, ''T. dicoccoides''. Wild emmer is the result of a hybridization between two diploid wild grasses, ''T. urartu'' and a wild goatgrass such as ''Aegilops searsii'' or ''[[Aegilops speltoides|Ae. speltoides]]''. The hybridization that formed wild emmer occurred in the wild, long before domestication.<ref name=Hancock /> * Hexaploid wheats evolved in farmers' fields. Either domesticated emmer or durum wheat hybridized with yet another wild diploid grass (''[[Aegilops tauschii]]'') to make the [[hexaploid]] wheats, [[spelt]] wheat and [[common wheat|bread wheat]].<ref name=Hancock /> == Plant Breeding == In traditional agricultural systems wheat is often grown as [[landraces]], informal farmer-maintained populations that often maintain high levels of morophological 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 many (ten or more) generations before release selections are identified to released as a variety or cultivar.<ref name=Bajaj /> F1 hybrid wheat cultivars should not be confused with wheat cultivars deriving from standard plant breeding. [[Heterosis]] 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 complete and normall y [[Self-pollination|self-pollinate]].<ref name=Bajaj>Bajaj, Y. P. S. (1990) ''Wheat''. Springer. pp. 161-63. ISBN 3-540-51809-6.</ref> Commercial hybrid wheat seed has been produced using chemical hybridizing agents, plant growth regulators that selectively interfere with pollen development, or naturally occurring cytoplasmic male sterility systems. Hybrid wheat has been a limited commercially success, in Europe (particularly [[France]]), the USA and South Africa.<ref>Basra, Amarjit S. (1999) ''Heterosis and Hybrid Seed Production in Agronomic Crops''. Haworth Press. pp. 81-82. ISBN 1-56022-876-8.</ref> == Hulled versus free-threshing wheat == [[image:usdaeinkorn1.jpg|thumbnail|100px|left|Spikelets of a hulled wheat, einkorn]] The four wild species of wheat, along with the domesticated varieties [[einkorn]],<ref name=Potts>Potts, D. T. (1996) ''Mesopotamia Civilization: The Material Foundations'' Cornell University Press. p. 62. ISBN 0-8014-3339-8.</ref> [[emmer]]<ref>Nevo, Eviatar & A. B. Korol & A. Beiles & T. Fahima. (2002) ''Evolution of Wild Emmer and Wheat Improvement: Population Genetics, Genetic Resources, and Genome...''. Springer. p. 8. ISBN 3-540-41750-8.</ref> and [[spelt]],<ref>Vaughan, J. G. & P. A. Judd. (2003) ''The Oxford Book of Health Foods''. Oxford University Press. p. 35. ISBN 0-19-850459-4.</ref> have hulls (in German, ''Spelzweizen''). This more primitive morphology 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. In contrast, 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. Hulled wheats are often stored as spikelets because the toughened glumes give good protection against pests of stored grain.<ref name=Potts /> == Naming == {{details|Wheat taxonomy}} There are many botanical classification systems used for wheat species, discussed in a separate article on [[Wheat taxonomy]]. 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]] vs. spring wheat,<ref name=CVDE /> by [[gluten]] content, such as hard wheat (high protein content) vs. soft wheat (high starch content), or by grain color (red, white or amber). ;Major cultivated species of wheat *'''[[Common wheat]]''' or '''Bread wheat''' — (''T. aestivum'') A [[ploidy|hexaploid]] species that is the most widely cultivated in the world. *'''[[Durum]]''' — (''T. durum'') The only tetraploid form of wheat widely used today, and the second most widely cultivated wheat. *'''[[Einkorn]]''' — (''T. monococcum'') A [[diploid]] species with wild and cultivated variants. Domesticated at the same time as emmer wheat, but never reached the same importance. *'''[[Emmer]]''' — (''T. dicoccon'') A [[ploidy|tetraploid]] species, cultivated in ancient times but no longer in widespread use. *'''[[Spelt]]''' — (''T. spelta'') Another hexaploid species cultivated in limited quantities. == Economics == [[Image:Wheat in sack.jpg|left|thumb|Sack of wheat]] [[Image:cracked_wheat.jpg|right|thumb|Cracked wheat]] Harvested wheat grain that enters trade is classified according to grain properties (see below) for the purposes of the [[commodity markets|commodities market]]. Wheat buyers use the classifications to help determine which wheat to purchase as each class has special uses. Wheat producers determine which classes of wheat are the most profitable to cultivate with this system. Wheat is widely cultivated as a [[cash crop]] because it produces a good yield per unit area, grows well in a [[temperate climate]] even with a moderately short [[growing season]], and yields a v ersatile, high-quality [[flour]] that is widely used in [[baking]]. Most [[bread]]s are made with wheat flour, including many breads named for the other grains they contain like most [[rye]] and [[oat]] breads. [[foods made from wheat|Many other popular foods]] are made from wheat flour as well, resulting in a large demand for the grain even in economies with a significant food [[economic surplus|surplus]]. ==Costs and returns== [[Image:2005wheat.PNG|thumb|right|Wheat output in 2005]] In Western Europe target wheat yields attainable are around 8 [[tonnes]] per [[hectare]]. Until recently a tonne of wheat was worth around 90 [[euros]] per tonne, giving a total income of €630 per hectare for an average yield of 7 tonnes per hectare. [[European Union]] subsidies available in 2006 add €400 per hectare, giving a total income of €1,030 per hectare. In some instances the [[straw]] yield of around 4 tonnes per hectare may be saleable at between €9 and €30 per tonne. [[Seed]], [[fertiliser]] and [[pesticide]]s cost around €60, €100 and €160 respectively. [[Labour]] cost comes to about €200, [[Power]] and [[Machinery]] €200, while [[rent]] and [[overheads]] come to around €250 per hectare for a large scale [[arable]] farm of over 200 hectares. Smaller farms would have higher costs due to economy of scale differences. With total costs of €970, a small [[profit]] of €60 per hectare, or €12,000 per year income for 200 hectares is available to the farmer for living expenses and [[loan]] repayments. The recent world price rises (2006) for wheat as a commodity could bring in as much as €400 per hectare extra for producers. Growing organic wheat typically reduces yield slightly but costs significantly less as there are no fertiliser and pesticide costs. Seed costs are typically higher, unless the farmer saves his own seed, and arguably labour and machinery costs are higher for the organic crop. These factors are offset by the higher price fetched by organic wheat. ==Production and consumption statistics== [[Image:Wheat-haHula-ISRAEL2.JPG|thumb|right|180px|A mature wheat field, in northern Israel]] {| class="wikitable" align=left style="clear:left" ! colspan=2|Top Ten Wheat Producers — 2005<br>(million metric ton) |- | {{CHN}} || align="right" | 96 |- | {{IND}} || align="right" | 72 |- | {{USA}} || align="right" | 57 |- | {{RUS}} || align="right" | 46 |- | {{FRA}} || align="right" | 37 |- | {{CAN}} || align="right" | 26 |- | {{AUS}}|| align="right" | 24 |- | {{GER}} || align="right" | 24 |- | {{PAK}} || align="right" | 22 |- | {{TUR}} || align="right" | 21 |- |'''World Total''' || align="right" | '''626''' |- |colspan=2|''Source: <br>[[UN Food & Agriculture Organisation]] (FAO)''<ref>[http://faostat.fao.org/site/340/default.aspx]</ref> |} In 1997, global per capita wheat consumption was 101 kg, with the highest per capita consumption (623 kg) found in [[Denmark]]. ''See also [[International wheat production statistics]]''. Unlike rice, wheat production is more widespread globally though China's share is almost one-sixth of the world. ==Agronomy== [[image:Spiklet.JPG|thumb|Wheat spikelet with the three anthers sticking out.]] While winter wheat lies dormant during a winter freeze, wheat normally requires between 110 and 130 days between planting and harvest, depending upon climate, seed type, and soil conditions. Crop management decisions require the knowledge of stage of development of the crop. In particular, spring [[fertilizer]]s applications, [[herbicide]]s, [[fungicide]]s, [[growth regulator]]s are typically applied at specific stages of plant development. For example, current recommendations often indicate the second application of nitrogen be done when the ear (not visible at this stage) is about 1 cm in size (Z31 on [[Zadoks scale]]). Knowledge of stages is also interesting to identify periods of higher risk, in terms of climate. For example, the meiosis stage is extremely susceptible to low temperatures (under 4 °C) or high temperatures (over 25 °C). Farmers also benefit from knowing when the flag leaf (last leaf) a ppears as this leaf represents about 75% of photosynthesis reactions during the grain filling period and as such should be preserved from disease or insect attacks to ensure a good yield. Several systems exist to identify crop stages, with the [[Feekes scale|Feekes]] and [[Zadoks scale]]s being the most widely used. Each scale is a standard system which describes successive stages reached by the crop during the agricultural season. *Wheat at the anthesis stage (face and side view) {| |[[image:WheatFlower1.jpg|thumb|none|]] |[[image:WheatFlower3.JPG|thumb|none|]] |} ;Diseases {{Main|Wheat diseases|List of wheat diseases}} Estimates of the amount of wheat production lost owing to plant diseases vary between 10-25% in Missouri.<ref>[http://muextension.missouri.edu/explore/agguides/crops/g04319.htm]</ref> A wide range of organisms infect wheat, of which the most important are viruses and fungi. ;Pests Wheat is used as a food plant by the [[larva]]e of some [[Lepidoptera]] species including [[Flame (moth)|The Flame]], [[Rustic Shoulder-knot]], [[Setaceous Hebrew Character]] and [[Turnip Moth]]. == Wheat in the United States ==<!-- This section is linked from [[Bowbells, North Dakota]] --> {| align=right |[[Image:Wheat harvest.jpg|thumb|Wheat harvest on the Palouse.]] |[[Image:CombineWheat0654.JPG|thumb|Combining wheat in Hemingway, South Carolina.]] |[[Image:Harvestingwheatwashigton.JPG|thumb|Combining wheat in Washington.]] |} Classes used in the United States are *'''[[Durum]]''' — Very hard, translucent, light colored grain used to make [[semolina]] flour for [[pasta]]. *'''Hard Red Spring''' — Hard, brownish, high [[protein]] 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 at the [[Minneapolis Grain Exchange]]. *'''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 by the [[Kansas City Board of Trade]]. *'''Soft Red Winter''' — Soft, low protein wheat used for cakes, pie crusts, biscuits, and muffins. Cake flour, pastry flour, and some self-rising flours with baking powder and salt added for example, are made from soft red winter wheat. It is primarily traded by the [[Chicago Board of Trade]]. *'''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. Hard wheats are harder to process and red wheats may need bleaching. Therefore, soft and white wheats usually command higher prices than hard and red wheats on the commodities market. ==As a food== Raw wheat seeds are a food ingredient called [[Whole grain|whole wheat]]. They can be powdered into [[flour]], germinated and dried creating [[malt]], crushed and de-branned into [[cracked wheat]], parboiled (or steamed), dried, crushed and de-branned into [[bulgur]], or processed into [[semolina]], [[pasta]], or [[roux]]. They are a major ingredient in such foods as [[bread]], [[breakfast cereal]]s (eg [[Wheatena]], [[Cream of Wheat]]), [[roti]] (Indian bread), [[naan]], [[porridge]], [[Cracker (food)|cracker]]s, [[biscuit]]s, [[pancake]]s, [[cake]]s, and [[gravy]]. ==Nutrition== 100 grams of hard red winter wheat contains about 12.6 grams of [[protein]], 1.5 grams of total [[fat]], 71 grams of [[carbohydrate]] (by difference), 12.2 grams of dietary [[fiber]], and 3.2 mg of [[iron]] or 17% of the amount required daily. 100 grams of hard red spring wheat contains about 15.4 grams of [[protein]], 1.9 grams of total [[fat]], 68 grams of [[carbohydrate]] (by difference), 12.2 grams of dietary [[fiber]], and 3.6 mg of [[iron]] or 20% of the amo unt required daily.<ref name=USDA_ARS>[http://www.nal.usda.gov/fnic/foodcomp/search/ USDA National Nutrient Database for Standard Reference], Release 19 (2006)</ref> [[Gluten]] protein found in wheat (and other [[Triticeae]]) is hard to digest, and intolerable for people with [[celiac disease]] (an autoimmune disorder in ~1% of Indo-European populations). ==Footnotes== {{reflist|2}} ==References== *Bonjean, A.P., and W.J. Angus (editors). The World Wheat Book: a history of wheat breeding. Lavoisier Publ., Paris. 1131 pp. (2001). ISBN 2-7430-0402-9. *[http://www.economist.com/science/displaystory.cfm?story_id=5323362&no_na_tran=1 Ears of plenty: The story of wheat], [[The Economist]], December 24th 2005, pp. 28-30 *Garnsey Peter, Grain for Rome, in Garnsey P., Hopkins K., Whittaker C. R. (editors), Trade in the Ancient Economy, Chatto & Windus, London 1983 *Jasny Naum, ''The daily bread of ancient Greeks and Romans'', Ex Officina Templi, Brugis 1950 *Jasny Naum, ''The Wheats of Classical Antiquity, J''. Hopkins Press, Baltimore 1944 *Heiser Charles B., ''Seed to civilisation. The story of food,'' Harvard University Press, Harvard Mass. 1990 *Harlan Jack R., ''Crops and man'', American Society of Agronomy, Madison 1975 *Saltini Antonio, ''I semi della civiltà. Grano, riso e mais nella storia delle società umane'', Prefazione di Luigi Bernabò Brea, Avenue Media, Bologna 1996 *Sauer Jonathan D., ''Geography of Crop Plants. A Select Roster'', CRC Press, Boca Raton ==See also== *[[Bran]] *[[Chaff]] *[[Husk]] ==External links== {{commons}} *[http://www.abc.net.au/catalyst/stories/s1913579.htm Watch Australian science documentary on developing drought-resistant wheat] *[http://www.wheatfoods.org/ WHEAT FOODS COUNCIL] Est. 1972 *[http://www.wheatworld.org/ NAWG] — Web site of the [[National Association of Wheat Growers]] *[http://www.cimmyt.org/ CIMMYT] — Web site of the [[International Maize and Wheat Improvement Center]] *[http://www.hort.purdue.edu/newcrop/crops/wheat.html Triticum species] at [[Purdue University]] *[http://www.genetics.org/cgi/content/full/168/2/1087 A Workshop Report on Wheat Genome Sequencing] *[http://www.ipgri.cgiar.org/publications/pdf/54.pdf Proceedings of the First International Workshop on Hulled Wheats] (PDF) July 1995 *[http://www.genome.org/cgi/content/full/10/10/1509 Molecular Genetic Maps in Wild Emmer Wheat] *[http://www.skyways.org/orgs/fordco/malin/ Winter Wheat in the Golden Belt of Kansas] by James C. Malin, University of Kansas, 1944 *[http://digital.library.unt.edu/permalink/meta-dc-1510:1 ''Varieties of club wheat''] hosted by the [http://digital.library.unt.edu/browse/department/govdocs/ UNT Government Documents Department] {{Wheat}} {{Cereals}} [[Category:Biofuels]] [[Category:Wheat| ]] [[category:Cereals]] [[Category:Crops]] {{Link FA|es}}

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