Wheat

<p><a href="http://en.wikipedia.org/wiki/Wheat" title="Wheat">Wheat</a>'s <a href="http://en.wikipedia.org/wiki/Adaptation" title="Adaptation">adaptation</a> to allow aluminium tolerance is such that the aluminium induces a release of <a href="http://en.wikipedia.org/wiki/Organic_compound" title="Organic compound">organic compounds</a> that bind to the harmful aluminium <a href="http://en.wikipedia.org/wiki/Cations" title="Cations" class="mw-redirect">cations</a>. <a href="http://en.wikipedia.org/wiki/Sorghum" title="Sorghum">Sorghum</a> is believed to have the same tolerance mechanism. The first gene for aluminium tolerance has been identified in wheat. It was shown that sorghum's aluminium tolerance is controlled by a single gene, as for wheat.<sup id="cite_ref-89" class="reference"><a href="http://en.wikipedia.org/wiki/Aluminium#cite_note-89">[90]</a></sup> This is not the case in all plants.</p>

<p>

<b>Wheat</b> (<i>Triticum</i> spp.)<sup id="cite_ref-Belderok_0-0" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-Belderok-0">[1]</a></sup> is a <a href="http://en.wikipedia.org/wiki/Cereal" title="Cereal">cereal grain</a>, originally from the <a href="http://en.wikipedia.org/wiki/Fertile_Crescent" title="Fertile Crescent">Fertile Crescent</a> region of the <a href="http://en.wikipedia.org/wiki/Near_East" title="Near East">Near East</a>, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced <a href="http://en.wikipedia.org/wiki/Cereal" title="Cereal">cereal</a> after <a href="http://en.wikipedia.org/wiki/Maize" title="Maize">maize</a> (784 million tons) and <a href="http://en.wikipedia.org/wiki/Rice" title="Rice">rice</a> (651 million tons).<sup id="cite_ref-1" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-1">[2]</a></sup> In 2009, world production of wheat was 682 million tons, making it the second most-produced cereal after maize (817 million tons), and with rice as close third (679 million tons).<sup id="cite_ref-OSU2009_2-0" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-OSU2009-2">[3]</a></sup></p>

<p>

Wheat is grown on more land area than any other commercial crop and is the most important staple food for humans. World trade in wheat is greater than for all other crops combined.<sup id="cite_ref-WheatBread_3-0" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-WheatBread-3">[4]</a></sup> Globally, wheat is the leading source of vegetable protein in human food, having a higher protein content than either maize (corn) or rice, the other major cereals. In terms of total production tonnages used for food, it is currently second to rice as the main human food crop and ahead of maize, after allowing for maize's more extensive use in animal feeds.</p>

<p>

Wheat was a key factor enabling the emergence of city-based societies at the start of civilization because it was one of the first crops that could be easily cultivated on a large scale, and had the additional advantage of yielding a harvest that provides long-term storage of food. </p>

<p>

Wheat contributed to the emergence of city-states in the Fertile Crescent, including the Babylonian and Assyrian empires. Wheat <a href="http://en.wikipedia.org/wiki/Caryopsis" title="Caryopsis">grain</a> is a <a href="http://en.wikipedia.org/wiki/Staple_food" title="Staple food">staple food</a> used to make <a href="http://en.wikipedia.org/wiki/Flour" title="Flour">flour</a> for leavened, flat and steamed <a href="http://en.wikipedia.org/wiki/Bread" title="Bread">breads</a>, biscuits, cookies, <a href="http://en.wikipedia.org/wiki/Cake" title="Cake">cakes</a>, breakfast cereal, pasta, noodles, <a href="http://en.wikipedia.org/wiki/Couscous" title="Couscous">couscous</a><sup id="cite_ref-4" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-4">[5]</a></sup> and for <a href="http://en.wikipedia.org/wiki/Fermentation_%28food%29" title="Fermentation (food)">fermentation</a> to make beer,<sup id="cite_ref-5" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-5">[6]</a></sup> other <a href="http://en.wikipedia.org/wiki/Alcoholic_beverage" title="Alcoholic beverage">alcoholic beverages</a>,<sup id="cite_ref-6" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-6">[7]</a></sup> or <a href="http://en.wikipedia.org/wiki/Biofuel" title="Biofuel">biofuel</a>.<sup id="cite_ref-7" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-7">[8]</a></sup></p>

<p>

Wheat is planted to a limited extent as a <a href="http://en.wikipedia.org/wiki/Fodder" title="Fodder">forage crop</a> for livestock, and its straw can be used as a construction material for roofing <a href="http://en.wikipedia.org/wiki/Thatch" title="Thatch" class="mw-redirect">thatch</a>.<sup id="cite_ref-8" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-8">[9]</a></sup><sup id="cite_ref-CVDE_9-0" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-CVDE-9">[10]</a></sup> The <a href="http://en.wikipedia.org/wiki/Whole_grain" title="Whole grain">whole grain</a> can be milled to leave just the <a href="http://en.wikipedia.org/wiki/Endosperm" title="Endosperm">endosperm</a> for white flour. The products of this are <a href="http://en.wikipedia.org/wiki/Dietary_bran" title="Dietary bran" class="mw-redirect">bran</a> and <a href="http://en.wikipedia.org/wiki/Cereal_germ" title="Cereal germ">germ</a>. </p>

<p>

The whole grain is a concentrated source of <a href="http://en.wikipedia.org/wiki/Vitamin" title="Vitamin">vitamins</a>, <a href="http://en.wikipedia.org/wiki/Minerals" title="Minerals" class="mw-redirect">minerals</a>, and <a href="http://en.wikipedia.org/wiki/Protein" title="Protein">protein</a>, while the refined grain is mostly <a href="http://en.wikipedia.org/wiki/Starch" title="Starch">starch</a>.

 </p>

<h2>Genetics</h2>

Spikelets of a hulled wheat, <a href="http://en.wikipedia.org/wiki/Einkorn" title="Einkorn" class="mw-redirect">einkorn</a></div>

</div>

<p>Wheat genetics is more complicated than that of most other domesticated species. Some wheat species are <a href="http://en.wikipedia.org/wiki/Diploid" title="Diploid" class="mw-redirect">diploid</a>, with two sets of chromosomes, but many are stable <a href="http://en.wikipedia.org/wiki/Polyploidy" title="Polyploidy" class="mw-redirect">polyploids</a>, with four sets of chromosomes (<a href="http://en.wikipedia.org/wiki/Tetraploid" title="Tetraploid" class="mw-redirect">tetraploid</a>) or six (<a href="http://en.wikipedia.org/wiki/Hexaploid" title="Hexaploid" class="mw-redirect">hexaploid</a>).<sup id="cite_ref-Hancock_21-0" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-Hancock-21">[22]</a></sup></p>

<ul>

<li><a href="http://en.wikipedia.org/wiki/Einkorn" title="Einkorn" class="mw-redirect">Einkorn</a> wheat (<i>T. monococcum</i>) is diploid (AA, two complements of seven chromosomes, 2n=14).<sup id="cite_ref-Belderok_0-1" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-Belderok-0">[1]</a></sup></li>

<li>Most tetraploid wheats (e.g. <a href="http://en.wikipedia.org/wiki/Emmer" title="Emmer">emmer</a> and <a href="http://en.wikipedia.org/wiki/Durum" title="Durum">durum wheat</a>) are derived from wild emmer, <i>T. dicoccoides</i>. Wild emmer is itself the result of a hybridization between two diploid wild grasses, <i>T. urartu</i> and a wild goatgrass such as <i>Aegilops searsii</i> or <i><a href="http://en.wikipedia.org/wiki/Aegilops_speltoides" title="Aegilops speltoides">Ae. speltoides</a></i>. The unknown grass has never been identified among now surviving wild grasses, but the closest living relative is <i>Aegilops speltoides</i>.<sup class="Template-Fact" >[<i><a href="http://en.wikipedia.org/wiki/Wikipedia:Citation_needed" title="Wikipedia:Citation needed">citation needed</a></i>]</sup> The hybridization that formed wild emmer (AABB) occurred in the wild, long before domestication,<sup id="cite_ref-Hancock_21-1" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-Hancock-21">[22]</a></sup> and was driven by natural selection.</li>

</ul>

<ul>

<li>Hexaploid wheats evolved in farmers' fields. Either domesticated emmer or durum wheat hybridized with yet another wild diploid grass (<i><a href="http://en.wikipedia.org/wiki/Aegilops_tauschii" title="Aegilops tauschii" class="mw-redirect">Aegilops tauschii</a></i>) to make the <a href="http://en.wikipedia.org/wiki/Hexaploid" title="Hexaploid" class="mw-redirect">hexaploid</a> wheats, <a href="http://en.wikipedia.org/wiki/Spelt" title="Spelt">spelt</a> wheat and <a href="http://en.wikipedia.org/wiki/Common_wheat" title="Common wheat">bread wheat</a>.<sup id="cite_ref-Hancock_21-2" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-Hancock-21">[22]</a></sup> These have <i>three</i> sets of paired chromosomes, three times as many as in diploid wheat.</li>

</ul>

<p>The presence of certain versions of wheat genes has been important for crop yields. Apart from mutant versions of genes selected in antiquity during domestication, there has been more recent deliberate selection of <a href="http://en.wikipedia.org/wiki/Alleles" title="Alleles" class="mw-redirect">alleles</a> that affect growth characteristics. Genes for the 'dwarfing' trait, first used by <a href="http://en.wikipedia.org/wiki/Norin_10_wheat" title="Norin 10 wheat">Japanese wheat breeders</a> to produce short-stalked wheat, have had a huge effect on wheat yields world-wide, and were major factors in the success of the <a href="http://en.wikipedia.org/wiki/Green_Revolution" title="Green Revolution">Green Revolution</a> in Mexico and Asia. 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 acreage was planted to semi-dwarf wheats, giving both increased yields and better response to nitrogenous fertilizer.

Wild grasses in the genus <i>Triticum</i> and related genera, and grasses such as <a href="http://en.wikipedia.org/wiki/Rye" title="Rye">rye</a> have been a source of many disease-resistance traits for cultivated wheat <a href="http://en.wikipedia.org/wiki/Transgenic_plant" title="Transgenic plant" class="mw-redirect">breeding</a> since the 1930s.<sup id="cite_ref-22" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-22">[23]</a></sup>

<a href="http://en.wikipedia.org/wiki/Heterosis" title="Heterosis">Heterosis</a>, 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 <a href="http://en.wikipedia.org/wiki/Maize" title="Maize">maize</a>) because wheat flowers are complete and normally <a href="http://en.wikipedia.org/wiki/Self-pollination" title="Self-pollination">self-pollinate</a>. Commercial hybrid wheat seed has been produced using chemical hybridizing agents; these chemicals selectively interfere with pollen development, or naturally occurring cytoplasmic male sterility systems. Hybrid wheat has been a limited commercial success in Europe (particularly <a href="http://en.wikipedia.org/wiki/France" title="France">France</a>), the USA and South Africa.<sup id="cite_ref-23" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-23">[24]</a></sup> F1 hybrid wheat cultivars should not be confused with the standard method of breeding inbred wheat cultivars by crossing two lines using hand emasculation, then selfing or inbreeding the progeny many (ten or more) generations before release selections are identified to be released as a variety or cultivar.

Synthetic hexaploids made by crossing the wild goatgrass wheat ancestor <i>Aegilops tauschii</i> and various durum wheats are now being deployed, and these increase the genetic diversity of cultivated wheats.<sup id="cite_ref-24" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-24">[25]</a></sup>

<a href="http://en.wikipedia.org/wiki/Stomata" title="Stomata" class="mw-redirect">Stomata</a> (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 <a href="http://en.wikipedia.org/wiki/Transpiration" title="Transpiration">transpiration</a>. Basic physiological investigation of these gas exchange processes has yielded valuable carbon <a href="http://en.wikipedia.org/wiki/Isotope" title="Isotope">isotope</a> 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.<sup id="cite_ref-25" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-25">[26]</a></sup>

In 2010, a team of UK scientists funded by <a href="http://en.wikipedia.org/wiki/BBSRC" title="BBSRC" class="mw-redirect">BBSRC</a> 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).<sup id="cite_ref-26" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-26">[27]</a></sup> This was the expressed genome and 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.<sup id="cite_ref-27" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-27">[28]</a></sup> A fully annotated sequence is being assembled by a global consortium (IWGSC <a rel="nofollow" class="external free" href="http://www.wheatgenome.org/">http://www.wheatgenome.org/</a>), including members of this team.</p>

<h2>[<a href="http://en.wikipedia.org/w/index.php?title=Wheat&action=edit&section=5" title="Edit section: Plant breeding">edit</a>] Plant breeding</h2>

<div class="rellink relarticle mainarticle">Main article: <a href="http://en.wikipedia.org/wiki/Physiological_and_molecular_wheat_breeding" title="Physiological and molecular wheat breeding">Physiological and molecular wheat breeding</a></div>

Sheaved and stooked wheat</div>

</div>

Wheat</div>

</div>

Wheat</div>

</div>

<p>In traditional agricultural systems wheat populations often consist of <a href="http://en.wikipedia.org/wiki/Landraces" title="Landraces" class="mw-redirect">landraces</a>, 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 <a href="http://en.wikipedia.org/wiki/Mendelian_genetics" title="Mendelian genetics" class="mw-redirect">Mendelian genetics</a>. The standard method of breeding inbred wheat cultivars is by crossing two lines using hand emasculation, then selfing or inbreeding the progeny. Selections are <i>identified</i> (shown to have the genes responsible for the varietal differences) ten or more generations before release as a variety or cultivar.<sup id="cite_ref-Bajaj_28-0" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-Bajaj-28">[29]</a></sup>

<a href="http://en.wikipedia.org/wiki/F1_hybrid" title="F1 hybrid">F1 hybrid</a> wheat cultivars should not be confused with wheat cultivars deriving from standard <a href="http://en.wikipedia.org/wiki/Plant_breeding" title="Plant breeding">plant breeding</a>. <a href="http://en.wikipedia.org/wiki/Heterosis" title="Heterosis">Heterosis</a> 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 <a href="http://en.wikipedia.org/wiki/Maize" title="Maize">maize</a> because wheat flowers are complete and normally <a href="http://en.wikipedia.org/wiki/Self-pollination" title="Self-pollination">self-pollinate</a>.<sup id="cite_ref-Bajaj_28-1" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-Bajaj-28">[29]</a></sup> Commercial hybrid wheat seed has been produced using chemical hybridizing agents, <a href="http://en.wikipedia.org/wiki/Plant_hormone" title="Plant hormone">plant growth regulators</a> that selectively interfere with pollen development, or naturally occurring <a href="http://en.wikipedia.org/wiki/Cytoplasmic_male_sterility" title="Cytoplasmic male sterility">cytoplasmic male sterility</a> systems. Hybrid wheat has been a limited commercial success in Europe (particularly <a href="http://en.wikipedia.org/wiki/France" title="France">France</a>), the <a href="http://en.wikipedia.org/wiki/United_States" title="United States">United States</a> and South Africa.<sup id="cite_ref-29" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-29">[30]</a></sup>

The major breeding objectives include high grain yield, good quality, disease and insect resistance and tolerance to abiotic stresses include 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: <a href="http://en.wikipedia.org/wiki/Eyespot%28wheat%29" title="Eyespot (wheat)">eyespot</a>, <a href="http://en.wikipedia.org/wiki/Phaeosphaeria_nodorum" title="Phaeosphaeria nodorum">Stagonospora nodorum blotch</a> (also known as glume blotch), <a href="http://en.wikipedia.org/wiki/Wheat_yellow_rust" title="Wheat yellow rust">yellow</a> or <a href="http://en.wikipedia.org/wiki/Wheat_yellow_rust" title="Wheat yellow rust">stripe rust</a>, <a href="http://en.wikipedia.org/wiki/Powdery_mildew#Powdery_mildew_of_wheat" title="Powdery mildew">powdery mildew</a>, <a href="http://en.wikipedia.org/wiki/Septoria_tritici" title="Septoria tritici">Septoria tritici blotch</a> (sometimes known as leaf blotch), <a href="http://en.wikipedia.org/wiki/Wheat_leaf_rust" title="Wheat leaf rust">brown</a> or <a href="http://en.wikipedia.org/wiki/Wheat_leaf_rust" title="Wheat leaf rust">leaf rust</a>, <a href="http://en.wikipedia.org/wiki/Fusarium_ear_blight" title="Fusarium ear blight">Fusarium head blight</a>, <a href="http://en.wikipedia.org/wiki/Pyrenophora_tritici-repentis" title="Pyrenophora tritici-repentis">tan spot</a> and <a href="http://en.wikipedia.org/wiki/Stem_rust" title="Stem rust">stem rust</a>. In tropical areas, <a href="http://en.wikipedia.org/wiki/Spot_blotch%28wheat%29" title="Spot blotch (wheat)">spot blotch</a> (also known as Helminthosporium leaf blight) is also important.</p>

<h2>[<a href="http://en.wikipedia.org/w/index.php?title=Wheat&action=edit&section=6" title="Edit section: Hulled versus free-threshing wheat">edit</a>] Hulled versus free-threshing wheat</h2>

A mature wheat field in Israel</div>

</div>

<p>The four wild species of wheat, along with the domesticated varieties <a href="http://en.wikipedia.org/wiki/Einkorn" title="Einkorn" class="mw-redirect">einkorn</a>,<sup id="cite_ref-Potts_30-0" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-Potts-30">[31]</a></sup> <a href="http://en.wikipedia.org/wiki/Emmer" title="Emmer">emmer</a><sup id="cite_ref-31" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-31">[32]</a></sup> and <a href="http://en.wikipedia.org/wiki/Spelt" title="Spelt">spelt</a>,<sup id="cite_ref-32" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-32">[33]</a></sup> 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. 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.<sup id="cite_ref-Potts_30-1" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-Potts-30">[31]</a></sup></p>

<h2>[<a href="http://en.wikipedia.org/w/index.php?title=Wheat&action=edit&section=7" title="Edit section: Naming">edit</a>] Naming</h2>

<div class="rellink boilerplate seealso">For more details on this topic, see <a href="http://en.wikipedia.org/wiki/Taxonomy_of_wheat" title="Taxonomy of wheat">Taxonomy of wheat</a>.</div>

Sack of wheat</div>

</div>

<p>There are many botanical classification systems used for wheat species, discussed in a separate article on <a href="http://en.wikipedia.org/wiki/Wheat_taxonomy" title="Wheat taxonomy" class="mw-redirect">Wheat taxonomy</a>. 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:</p>

<ul>

<li>growing season, such as <a href="http://en.wikipedia.org/wiki/Winter_wheat" title="Winter wheat">winter wheat</a> vs. spring wheat,<sup id="cite_ref-CVDE_9-1" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-CVDE-9">[10]</a></sup> by <a href="http://en.wikipedia.org/wiki/Gluten" title="Gluten">gluten</a> content, such as hard wheat (high protein content) vs. soft wheat (high starch content), or by grain color (red, white or amber).</li>

<li><a href="http://en.wikipedia.org/wiki/Protein" title="Protein">Protein</a> content. Bread wheat protein content ranges from 10% in some soft wheats with high starch contents, to 15% in hard wheats.</li>

<li>The quality of the wheat protein <a href="http://en.wikipedia.org/wiki/Gluten" title="Gluten">gluten</a>. This protein can determine the suitability of a wheat to a particular dish. A strong and elastic gluten present in bread wheats enables <a href="http://en.wikipedia.org/wiki/Dough" title="Dough">dough</a> to trap carbon dioxide during leavening, but elastic gluten interferes with the rolling of <a href="http://en.wikipedia.org/wiki/Pasta" title="Pasta">pasta</a> into thin sheets. The gluten protein in durum wheats used for pasta is strong but not elastic.</li>

<li>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 <a href="http://en.wikipedia.org/wiki/Semolina" title="Semolina">semolina</a> flour made from it is due to a <a href="http://en.wikipedia.org/wiki/Carotenoid" title="Carotenoid">carotenoid</a> pigment called <a href="http://en.wikipedia.org/wiki/Lutein" title="Lutein">lutein</a>, which can be oxidized to a colorless form by enzymes present in the grain.</li>

</ul>

<h3>[<a href="http://en.wikipedia.org/w/index.php?title=Wheat&action=edit&section=8" title="Edit section: Major cultivated species of wheat">edit</a>] Major cultivated species of wheat</h3>

<ul>

<li><b><a href="http://en.wikipedia.org/wiki/Common_wheat" title="Common wheat">Common wheat</a></b> or <b>Bread wheat</b> (<i>T. aestivum</i>) – A <a href="http://en.wikipedia.org/wiki/Ploidy" title="Ploidy">hexaploid</a> species that is the most widely cultivated in the world.</li>

<li><b><a href="http://en.wikipedia.org/wiki/Durum" title="Durum">Durum</a></b> (<i>T. durum</i>) – The only tetraploid form of wheat widely used today, and the second most widely cultivated wheat.</li>

<li><b><a href="http://en.wikipedia.org/wiki/Einkorn" title="Einkorn" class="mw-redirect">Einkorn</a></b> (<i>T. monococcum</i>) – A <a href="http://en.wikipedia.org/wiki/Diploid" title="Diploid" class="mw-redirect">diploid</a> species with wild and cultivated variants. Domesticated at the same time as emmer wheat, but never reached the same importance.</li>

<li><b><a href="http://en.wikipedia.org/wiki/Emmer" title="Emmer">Emmer</a></b> (<i>T. dicoccum</i>) – A <a href="http://en.wikipedia.org/wiki/Ploidy" title="Ploidy">tetraploid</a> species, cultivated in <a href="http://en.wikipedia.org/wiki/Ancient_history" title="Ancient history">ancient times</a> but no longer in widespread use.</li>

<li><b><a href="http://en.wikipedia.org/wiki/Spelt" title="Spelt">Spelt</a></b> (<i>T. spelta</i>) – Another hexaploid species cultivated in limited quantities.</li>

</ul>

<p>Classes used in the United States are</p>

<ul>

<li><b><a href="http://en.wikipedia.org/wiki/Durum" title="Durum">Durum</a></b> – Very hard, translucent, light-colored grain used to make <a href="http://en.wikipedia.org/wiki/Semolina" title="Semolina">semolina</a> flour for <a href="http://en.wikipedia.org/wiki/Pasta" title="Pasta">pasta</a> and <a href="http://en.wikipedia.org/wiki/Bulghur" title="Bulghur" class="mw-redirect">bulghur</a>.</li>

<li><b>Hard Red Spring</b> – Hard, brownish, high-<a href="http://en.wikipedia.org/wiki/Protein" title="Protein">protein</a> 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 <a href="http://en.wikipedia.org/wiki/Minneapolis_Grain_Exchange" title="Minneapolis Grain Exchange">Minneapolis Grain Exchange</a>.</li>

<li><b>Hard Red Winter</b> – 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 <a href="http://en.wikipedia.org/wiki/Kansas_City_Board_of_Trade" title="Kansas City Board of Trade">Kansas City Board of Trade</a>. One variety is known as "turkey red wheat", and was brought to Kansas by <a href="http://en.wikipedia.org/wiki/Mennonite" title="Mennonite">Mennonite</a> immigrants from Russia.<sup id="cite_ref-33" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-33">[34]</a></sup></li>

<li><b>Soft Red Winter</b> – Soft, low-protein wheat used for cakes, pie crusts, biscuits, and muffins. Cake flour, pastry flour, and some self-rising flours with <a href="http://en.wikipedia.org/wiki/Baking_powder" title="Baking powder">baking powder</a> and salt added, for example, are made from soft red winter wheat. It is primarily traded by the <a href="http://en.wikipedia.org/wiki/Chicago_Board_of_Trade" title="Chicago Board of Trade">Chicago Board of Trade</a>.</li>

<li><b>Hard White</b> – Hard, light-colored, opaque, chalky, medium-protein wheat planted in dry, temperate areas. Used for bread and brewing.</li>

<li><b>Soft White</b> – 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.</li>

</ul>

<p>Red wheats may need bleaching; therefore, white wheats usually command higher prices than red wheats on the commodities market.</p>

Wheat is used in a wide variety of foods.</div>

</div>

<caption >Wheat <b>germ</b> crude (not whole grain)</caption>

<tbody>

<tr>

<th colspan="2" >Nutritional value per 100 g (3.5 oz)</th>

</tr>

<tr >

<th><a href="http://en.wikipedia.org/wiki/Food_energy" title="Food energy">Energy</a></th>

</tr>

<tr>

<th><a href="http://en.wikipedia.org/wiki/Carbohydrate" title="Carbohydrate">Carbohydrates</a></th>

</tr>

<tr>

<th>- <a href="http://en.wikipedia.org/wiki/Dietary_fiber" title="Dietary fiber">Dietary fiber</a></th>

</tr>

<tr>

</tr>

<tr>

<th><a href="http://en.wikipedia.org/wiki/Protein_%28nutrient%29" title="Protein (nutrient)">Protein</a></th>

</tr>

<tr>

<td><a href="http://en.wikipedia.org/wiki/Thiamine" title="Thiamine">Thiamine (vit. B<sub>1</sub>)</a></td>

</tr>

<tr>

<td><a href="http://en.wikipedia.org/wiki/Riboflavin" title="Riboflavin">Riboflavin (vit. B<sub>2</sub>)</a></td>

</tr>

<tr>

<td><a href="http://en.wikipedia.org/wiki/Niacin" title="Niacin">Niacin (vit. B<sub>3</sub>)</a></td>

</tr>

<tr>

<td><a href="http://en.wikipedia.org/wiki/Pantothenic_acid" title="Pantothenic acid">Pantothenic acid</a> (B<sub>5</sub>)</td>

</tr>

<tr>

<td><a href="http://en.wikipedia.org/wiki/Vitamin_B6" title="Vitamin B6">Vitamin B<sub>6</sub></a></td>

</tr>

<tr>

<td><a href="http://en.wikipedia.org/wiki/Folate" title="Folate" class="mw-redirect">Folate</a> (vit. B<sub>9</sub>)</td>

</tr>

<tr>

<td><a href="http://en.wikipedia.org/wiki/Calcium#Nutrition" title="Calcium">Calcium</a></td>

</tr>

<tr>

</tr>

<tr>

<td><a href="http://en.wikipedia.org/wiki/Magnesium_in_biology" title="Magnesium in biology">Magnesium</a></td>

</tr>

<tr>

<td><a href="http://en.wikipedia.org/wiki/Phosphorus#Biological_role" title="Phosphorus">Phosphorus</a></td>

</tr>

<tr>

<td><a href="http://en.wikipedia.org/wiki/Potassium#Potassium_in_the_diet_and_by_supplement" title="Potassium">Potassium</a></td>

</tr>

<tr>

</tr>

<tr>

<th><a href="http://en.wikipedia.org/wiki/Manganese" title="Manganese">Manganese</a> 13.301 mg</th>

</tr>

<tr >

<td colspan="2">Percentages are relative to <a href="http://en.wikipedia.org/wiki/Dietary_Reference_Intake" title="Dietary Reference Intake">US recommendations</a> for adults.

<small>Source: <a rel="nofollow" class="external text" href="http://www.nal.usda.gov/fnic/foodcomp/search/">USDA Nutrient Database</a></small></td>

</tr>

</tbody></table>

<p>Raw wheat can be ground into <a href="http://en.wikipedia.org/wiki/Wheat_flour" title="Wheat flour">flour</a> or, using hard durum wheat only, can be ground into <a href="http://en.wikipedia.org/wiki/Semolina" title="Semolina">semolina</a>; germinated and dried creating <a href="http://en.wikipedia.org/wiki/Malt" title="Malt">malt</a>; crushed or cut into cracked wheat; parboiled (or steamed), dried, crushed and de-branned into <a href="http://en.wikipedia.org/wiki/Bulgur" title="Bulgur">bulgur</a> also known as <a href="http://en.wikipedia.org/wiki/Groats" title="Groats" class="mw-redirect">groats</a>. If the raw wheat is broken into parts at the mill, as is usually done, the outer husk or <a href="http://en.wikipedia.org/wiki/Bran" title="Bran">bran</a> can be used several ways. Wheat is a major ingredient in such foods as bread, porridge, crackers, biscuits, <a href="http://en.wikipedia.org/wiki/Muesli" title="Muesli">Muesli</a>, <a href="http://en.wikipedia.org/wiki/Pancakes" title="Pancakes" class="mw-redirect">pancakes</a>, pies, pastries, cakes, cookies, muffins, rolls, doughnuts, gravy, <a href="http://en.wikipedia.org/wiki/Boza" title="Boza">boza</a> (a <a href="http://en.wikipedia.org/wiki/Alcoholic_beverage" title="Alcoholic beverage">fermented beverage</a>), and <a href="http://en.wikipedia.org/wiki/Breakfast_cereal" title="Breakfast cereal">breakfast cereals</a> (e.g., <a href="http://en.wikipedia.org/wiki/Wheatena" title="Wheatena">Wheatena</a>, <a href="http://en.wikipedia.org/wiki/Cream_of_Wheat" title="Cream of Wheat">Cream of Wheat</a>, <a href="http://en.wikipedia.org/wiki/Shredded_Wheat" title="Shredded Wheat" class="mw-redirect">Shredded Wheat</a>, and <a href="http://en.wikipedia.org/wiki/Wheaties" title="Wheaties">Wheaties</a>).</p>

<h3>[<a href="http://en.wikipedia.org/w/index.php?title=Wheat&action=edit&section=10" title="Edit section: Nutrition">edit</a>] Nutrition</h3>

<p>100 grams of hard red winter wheat contain about 12.6 grams of <a href="http://en.wikipedia.org/wiki/Protein" title="Protein">protein</a>, 1.5 grams of total <a href="http://en.wikipedia.org/wiki/Fat" title="Fat">fat</a>, 71 grams of <a href="http://en.wikipedia.org/wiki/Carbohydrate" title="Carbohydrate">carbohydrate</a> (by difference), 12.2 grams of dietary <a href="http://en.wikipedia.org/wiki/Fiber" title="Fiber">fiber</a>, and 3.2 mg of <a href="http://en.wikipedia.org/wiki/Iron" title="Iron">iron</a> (17% of the daily requirement); the same weight of hard red spring wheat contains about 15.4 grams of <a href="http://en.wikipedia.org/wiki/Protein" title="Protein">protein</a>, 1.9 grams of total <a href="http://en.wikipedia.org/wiki/Fat" title="Fat">fat</a>, 68 grams of <a href="http://en.wikipedia.org/wiki/Carbohydrate" title="Carbohydrate">carbohydrate</a> (by difference), 12.2 grams of dietary <a href="http://en.wikipedia.org/wiki/Fiber" title="Fiber">fiber</a>, and 3.6 mg of iron (20% of the daily requirement).<sup id="cite_ref-USDA_ARS_34-0" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-USDA_ARS-34">[35]</a></sup>

Much of the carbohydrate fraction of wheat is <a href="http://en.wikipedia.org/wiki/Starch" title="Starch">starch</a>. Wheat starch is an important commercial product of wheat, but second in economic value to <a href="http://en.wikipedia.org/wiki/Gluten" title="Gluten">wheat gluten</a>.<sup id="cite_ref-35" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-35">[36]</a></sup> The principal parts of wheat flour are gluten and starch. These can be separated in a kind of home experiment, by mixing flour and water to form a small ball of dough, and kneading it gently while rinsing it in a bowl of water. The starch falls out of the dough and sinks to the bottom of the bowl, leaving behind a ball of gluten.</p>

<h3>[<a href="http://en.wikipedia.org/w/index.php?title=Wheat&action=edit&section=11" title="Edit section: Nutritional importance of wheat">edit</a>] Nutritional importance of wheat</h3>

<p>Wheat is grown on more than 240 million hectares, larger than for any other crop. World trade in wheat is greater than for all other crops combined. With rice, wheat is world's most favored staple food. Wheat provides more nourishment for humans than any other food source. It is a major diet component because of the wheat plant’s agronomic adaptability with the ability to grow from near arctic regions to equator, from sea level to plains of Tibet (4000 meters above sea level). In addition to agronomic adaptability, wheat offers ease of grain storage and ease of converting grain into flour for making edible, palatable, interesting and satisfying foods. Wheat is the most important source of carbohydrate in a majority of countries.

Wheat protein is easily digested by nearly 99% of human population (see gluten sensitivity for exception). So is its starch. Wheat also contains a diversity of minerals, vitamins and fats (lipids). With a small amount of animal or legume protein added, a wheat-based meal is highly nutritious. A predominately wheat-based diet is higher in fiber than a meat-based diet.

The most common forms of wheat are white and red wheat. However, other natural forms of wheat exist. For example, in the highlands of Ethiopia grows purple wheat, a tetraploid species of wheat that is rich in anti-oxidants. Other commercially minor but nutritionally-promising species of naturally evolved wheat species include black, yellow and blue wheat.<sup id="cite_ref-36" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-36">[37]</a></sup>,<sup id="cite_ref-37" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-37">[38]</a></sup>,<sup id="cite_ref-WheatBread_3-1" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-WheatBread-3">[4]</a></sup></p>

<h3>[<a href="http://en.wikipedia.org/w/index.php?title=Wheat&action=edit&section=12" title="Edit section: Health concerns">edit</a>] Health concerns</h3>

<div class="rellink relarticle mainarticle">Main article: <a href="http://en.wikipedia.org/wiki/Gluten_sensitivity" title="Gluten sensitivity">Gluten sensitivity</a></div>

<p>Several screening studies in Europe, South America, Australasia, and the USA suggest that approximately 0.5–1% of these populations may have undetected coeliac disease.<sup id="cite_ref-VanHeelWest_38-0" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-VanHeelWest-38">[39]</a></sup> <a href="http://en.wikipedia.org/wiki/Coeliac_disease" title="Coeliac disease">coeliac</a> (also written as celiac) <a href="http://en.wikipedia.org/wiki/Disease" title="Disease">disease</a> is a condition that is caused by an adverse <a href="http://en.wikipedia.org/wiki/Immune_system" title="Immune system">immune system</a> reaction to <a href="http://en.wikipedia.org/wiki/Gliadin" title="Gliadin">gliadin</a>, a <a href="http://en.wikipedia.org/wiki/Gluten" title="Gluten">gluten</a> protein found in wheat (and similar proteins of the <a href="http://en.wikipedia.org/wiki/Tribe_%28biology%29" title="Tribe (biology)">tribe</a> <a href="http://en.wikipedia.org/wiki/Triticeae" title="Triticeae">Triticeae</a> which includes other species such as <a href="http://en.wikipedia.org/wiki/Barley" title="Barley">barley</a> and <a href="http://en.wikipedia.org/wiki/Rye" title="Rye">rye</a>). Upon exposure to gliadin, the enzyme <a href="http://en.wikipedia.org/wiki/Tissue_transglutaminase" title="Tissue transglutaminase">tissue transglutaminase</a> modifies the protein, and the immune system cross-reacts with the bowel tissue, causing an <a href="http://en.wikipedia.org/wiki/Inflammation" title="Inflammation">inflammatory reaction</a>. That leads to flattening of the lining of the <a href="http://en.wikipedia.org/wiki/Small_intestine" title="Small intestine">small intestine</a>, which <a href="http://en.wikipedia.org/wiki/Malabsorption" title="Malabsorption">interferes with the absorption</a> of nutrients. The only effective treatment is a lifelong <a href="http://en.wikipedia.org/wiki/Gluten-free_diet" title="Gluten-free diet">gluten-free diet</a>.

The estimate for people in the <a href="http://en.wikipedia.org/wiki/United_States" title="United States">United States</a> is between 0.5 and 1.0 percent of the population.<sup id="cite_ref-39" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-39">[40]</a></sup><sup id="cite_ref-40" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-40">[41]</a></sup><sup id="cite_ref-41" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-41">[42]</a></sup>

While the disease is caused by a reaction to wheat proteins, it is not the same as <a href="http://en.wikipedia.org/wiki/Wheat_allergy" title="Wheat allergy">wheat allergy</a>.</p>

<h3>[<a href="http://en.wikipedia.org/w/index.php?title=Wheat&action=edit&section=13" title="Edit section: Comparison of wheat with other major staple foods">edit</a>] Comparison of wheat with other major staple foods</h3>

<p>The following table shows the nutrient content of wheat and other major staple foods in a raw form.<sup id="cite_ref-42" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-42">[43]</a></sup>

Raw forms of these staples, however, aren't edible and can not 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 grains is remarkably different from that of raw form of these grains 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.).</p>

<tr>

<th>Synopsis<sup id="cite_ref-43" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-43">[44]</a></sup> ~ composition:</th>

<th><a href="http://en.wikipedia.org/wiki/Cassava" title="Cassava">Cassava</a><sup id="cite_ref-44" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-44">[45]</a></sup></th>

<th>Wheat<sup id="cite_ref-45" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-45">[46]</a></sup></th>

<th><a href="http://en.wikipedia.org/wiki/Maize" title="Maize">Sweetcorn</a><sup id="cite_ref-47" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-47">[48]</a></sup></th>

<th><a href="http://en.wikipedia.org/wiki/Potato" title="Potato">Potato</a><sup id="cite_ref-48" class="reference"><a href="http://en.wikipedia.org/wiki/Wheat#cite_note-48">[49]</a></sup></th>

</tr>

<tr>

<th>Component (per 100g portion, raw grain)</th>

<th>Amount</th>

</tr>

<tr>

<td>water (g)</td>

</tr>

<tr>

<td>energy (kJ)</td>

</tr>

<tr>

<td>protein (g)</td>

</tr>

<tr>

</tr>

<tr>

<td>carbohydrates (g)</td>

</tr>

<tr>

<td>fiber (g)</td>

</tr>

<tr>

<td>sugars (g)</td>

</tr>

<tr>

</tr>

<tr>

<td>manganese (mg)</td>

</tr>

<tr>

<td>calcium (mg)</td>

</tr>

<tr>

<td>magnesium (mg)</td>

</tr>

<tr>

<td>phosphorus (mg)</td>

</tr>

<tr>

<td>potassium (mg)</td>

</tr>

<tr>

</tr>

<tr>

<td>pantothenic acid (mg)</td>

</tr>

<tr>

</tr>

<tr>

<td>folate (µg)</td>

</tr>

<tr>

<td>thiamin (mg)</td>

</tr>

<tr>

<td>riboflavin (mg)</td>

</tr>

<tr>

<td>niacin (mg)</td>

</tr>

</tbody></table>

Wheat

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