Wheat
| Wheat | |
|---|---|
| |
| Scientific classification | |
| Kingdom: | |
| (unranked): | |
| (unranked): | |
| (unranked): | |
| Order: | |
| Family: | |
| Subfamily: | |
| Tribe: | |
| Genus: | Triticum |
| Species | |
|
T. aestivum References: | |
Wheat (Triticum spp.)[1] is a grass, originally from the Fertile Crescent region of the Near East, but now cultivated worldwide. In 2007 world production of wheat was 607 million tons, making it the third most-produced cereal after maize (784 million tons) and rice (651 million tons).[2] Wheat grain is a staple food used to make flour for leavened, flat and steamed breads, biscuits, cookies, cakes, breakfast cereal, pasta, noodles, couscous [3] and for fermentation to make beer,[4] other alcoholic beverages,[5] or biofuel.[6] Wheat is planted to a limited extent as a forage crop for livestock, and its straw can be used as a construction material for roofing thatch.[7][8]
History
![[icon]](/enwiki/wiki/File:Wiki_letter_w_cropped.svg){kind=small} | This section needs expansion. You can help by adding to it. (January 2010) |
Wheat has been cultivated domestically at least since 9,000 B.C. and probably earlier. micheal loves alex!! Domesticated Einkorn wheat at Nevalı Çori—40 miles (64 km) northwest of Gobekli Tepe in Turkey—has been dated to 9,000 B.C.[9] However evidence for the exploitation of wild barley has been dated to 23,000 B.C. and some say this is also true of pre-domesticated wheat.[10]
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 polyploids, with four sets of chromosomes (tetraploid) or six (hexaploid).[11]
- Einkorn wheat (T. monococcum) is diploid.[1]
- Most tetraploid wheats (e.g. emmer and 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 Ae. speltoides.[citation needed] The hybridization that formed wild emmer occurred in the wild, long before domestication.[11]
- Hexaploid wheats evolved in farmers' fields. Either domesticated emmer or durum wheat hybridized with yet another wild diploid grass (Aegilops cylindrica) to make the hexaploid wheats, spelt wheat and bread wheat.[11]
Plant 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.[12]
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 normally self-pollinate.[12] 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 commercial success in Europe (particularly France), the United States and South Africa.[13]
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: eyespot, Stagonospora nodorum blotch (also known as glume blotch), yellow or stripe rust, powdery mildew, Septoria tritici blotch (sometimes known as leaf blotch), brown or leaf rust, Fusarium head blight, tan spot and stem rust. In tropical areas, spot blotch (also known as Helminthosporium leaf blight) is also important.
Hulled versus free-threshing wheat
The four wild species of wheat, along with the domesticated varieties einkorn,[14] emmer[15] and spelt,[16] 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.[14]
Naming
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,[8] 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 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. dicoccum) A tetraploid species, cultivated in ancient times but no longer in widespread use.
- Spelt — (T. spelta) Another hexaploid species cultivated in limited quantities.
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. One variety is known as "turkey red wheat", and was brought to Kansas by Mennonite immigrants from Russia.[17]
- 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.
Red wheats may need bleaching, therefore white wheats usually command higher prices than red wheats on the commodities market.
As a food
| Nutritional value per 100 g (3.5 oz) | |||||||||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Energy | 1,506 kJ (360 kcal) | ||||||||||||||||||||||||||||||||||||
51.8 g | |||||||||||||||||||||||||||||||||||||
| Dietary fiber | 13.2 g | ||||||||||||||||||||||||||||||||||||
9.72 g | |||||||||||||||||||||||||||||||||||||
23.15 g | |||||||||||||||||||||||||||||||||||||
| |||||||||||||||||||||||||||||||||||||
| †Percentages estimated using US recommendations for adults,[18] except for potassium, which is estimated based on expert recommendation from the National Academies.[19] | |||||||||||||||||||||||||||||||||||||
Raw wheat can be powdered into flour; germinated and dried creating malt; crushed or cut into cracked wheat; parboiled (or steamed), dried, crushed and de-branned into bulgur; or processed into semolina, pasta, or roux. Wheat is a major ingredient in such foods as bread, porridge, crackers, biscuits, Muesli, pancakes, pies, pastries, cakes, cookies, muffins, rolls, doughnuts, gravy, boza (a fermented beverage), and breakfast cereals (e.g., Wheatena, Cream of Wheat, Shredded Wheat, and Wheaties).
Nutrition
100 grams of hard red winter wheat[clarification needed] contain 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 (17% of the daily requirement); the same weight 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 (20% of the daily requirement).[20]
Much of the carbohydrate fraction of wheat is starch. Wheat starch is an important commercial product of wheat, but second in economic value to wheat gluten.[21] 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.
Health concerns
Roughly 1% of Indo-European populations[22][23] has coeliac (also written as celiac) disease—a condition that is caused by an adverse immune system reaction to gliadin, a gluten protein found in wheat (and similar proteins of the tribe Triticeae which includes other species such as barley and rye). Upon exposure to gliadin, the enzyme tissue transglutaminase modifies the protein, and the immune system cross-reacts with the bowel tissue, causing an inflammatory reaction. That leads to flattening of the lining of the small intestine, which interferes with the absorption of nutrients. The only effective treatment is a lifelong gluten-free diet.
The estimate for people in the United States is between 0.5 and 1.0 percent of the population.[24][25][26]
While the disease is caused by a reaction to wheat proteins, it is not the same as wheat allergy.
Commercial use
Harvested wheat grain that enters trade is classified according to grain properties for the purposes of the 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 versatile, high-quality flour that is widely used in baking. Most breads are made with wheat flour, including many breads named for the other grains they contain like most rye 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 2007 there was a dramatic rise in the price of wheat due to freezes and flooding in the northern hemisphere and a drought in Australia. Wheat futures in September, 2007 for December and March delivery had risen above $9.00 a bushel, prices never seen before.[27] There were complaints in Italy about the high price of pasta.[28] This followed a wider trend of escalating food prices around the globe, driven in part by climatic conditions such as drought in Australia, the diversion of arable land to other uses (such as producing government-subsidised bio-oil crops), and later by some food-producing nations placing bans or restrictions on exports in order to satisfy their own consumers.
Other drivers affecting wheat prices include the movement to bio fuels (in 2008, a third of corn crops in the US are expected to be devoted to ethanol production)[citation needed] and rising incomes in developing countries, which is causing a shift in eating patterns from predominantly rice to more meat based diets (a rise in meat production equals a rise in grain consumption - seven kilograms of grain is required to produce one kilogram of beef.[29]
Production and consumption statistics
In 2003, global per capita wheat consumption was 67 kg, with the highest per capita consumption (239 kg) found in Kyrgyzstan.[30]
Unlike rice, wheat production is more widespread globally though China's share is almost one-sixth of the world.
| Top Ten Wheat Producers — 2007 (million metric ton) | |
|---|---|
 China |
109 |
 India |
75.8 |
 United States |
56 |
 Russia |
49 |
 France |
33 |
 Pakistan |
23 |
 Germany |
21 |
 Canada |
20 |
 Turkey |
17 |
 Argentina |
16 |
| World Total | 725 |
| Source: UN Food & Agriculture Organisation (FAO)[31] | |
Agronomy
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 applications, herbicides, fungicides, growth regulators 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) appears 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 and Zadoks scales 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
 |
Diseases
Estimates of the amount of wheat production lost owing to plant diseases vary between 10-25% in Missouri.[32] 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 larvae of some Lepidoptera (butterfly and moth) species including The Flame, Rustic Shoulder-knot, Setaceous Hebrew Character and Turnip Moth.
Futures contracts
Wheat futures are traded on the Chicago Board of Trade, Kansas City Board of Trade, and Minneapolis Grain Exchange, and have delivery dates in March (H), May (K), July (N), September (U), and December (Z).[33]
See also
References
- ^ a b Belderok, Bob & Hans Mesdag & Dingena A. Donner. (2000) Bread-Making Quality of Wheat. Springer. p.3. ISBN 0-7923-6383-3.
- ^ FAO (2007). "FAOSTAT". Retrieved 2009-05-05.
- ^ Cauvain, Stanley P. & Cauvain P. Cauvain. (2003) Bread Making. CRC Press. p. 540. ISBN 1-85573-553-9.
- ^ Palmer, John J. (2001) How to Brew. Defenestrative Pub Co. p. 233. ISBN 0-9710579-0-7.
- ^ Neill, Richard. (2002) Booze: The Drinks Bible for the 21st Century. Octopus Publishing Group - Cassell Illustrated. p. 112. ISBN 1-84188-196-1.
- ^ Department of Agriculture Appropriations for 1957: Hearings ... 84th Congress. 2d Session. United States House Committee on Appropriations. 1956. p. 242.
- ^ Smith, Albert E. (1995) Handbook of Weed Management Systems. Marcel Dekker. p. 411. ISBN 0-8247-9547-4.
- ^ a b Bridgwater, W. & Beatrice Aldrich. (1966) The Columbia-Viking Desk Encyclopedia. Columbia University. p. 1959.
- ^ "Which came first, monumental building projects or farming?". Archaeo News. 2008-12-14.
{{cite journal}}: Cite has empty unknown parameter:|coauthors=(help) - ^ Piperno, Dolores (2004-06-04). "Processing of wild cereal grains in the Upper Palaeolithic revealed by starch grain analysis". Nature (430): 670–673. doi:10.1038/nature02734.
{{cite journal}}: Check|authorlink=value (help); External link in|authorlink=|coauthors=ignored (|author=suggested) (help) - ^ a b c Hancock, James F. (2004) Plant Evolution and the Origin of Crop Species. CABI Publishing. ISBN 0-85199-685-X.
- ^ a b Bajaj, Y. P. S. (1990) Wheat. Springer. pp. 161-63. ISBN 3-540-51809-6.
- ^ Basra, Amarjit S. (1999) Heterosis and Hybrid Seed Production in Agronomic Crops. Haworth Press. pp. 81-82. ISBN 1-56022-876-8.
- ^ a b Potts, D. T. (1996) Mesopotamia Civilization: The Material Foundations Cornell University Press. p. 62. ISBN 0-8014-3339-8.
- ^ 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.
- ^ Vaughan, J. G. & P. A. Judd. (2003) The Oxford Book of Health Foods. Oxford University Press. p. 35. ISBN 0-19-850459-4.
- ^ Moon, David, "In the Russian Steppes: the Introduction of Russian Wheat on the Great Plains of the UNited States," Journal of Global History 3 (2008), 203-225
- ^ United States Food and Drug Administration (2024). "Daily Value on the Nutrition and Supplement Facts Labels". FDA. Archived from the original on 2024-03-27. Retrieved 2024-03-28.
- ^ National Academies of Sciences, Engineering, and Medicine; Health and Medicine Division; Food and Nutrition Board; Committee to Review the Dietary Reference Intakes for Sodium and Potassium (2019). "Chapter 4: Potassium: Dietary Reference Intakes for Adequacy". In Oria, Maria; Harrison, Meghan; Stallings, Virginia A. (eds.). Dietary Reference Intakes for Sodium and Potassium. The National Academies Collection: Reports funded by National Institutes of Health. Washington, DC: National Academies Press (US). pp. 120–121. doi:10.17226/25353. ISBN 978-0-309-48834-1. PMID 30844154. Retrieved 2024-12-05.
- ^ USDA National Nutrient Database for Standard Reference, Release 19 (2006)
- ^ International Starch Institute, TM 33-1www - ISI Technical Memorandum on Production of Wheat Starch. Retrieved August 11, 2008.
- ^ van Heel D, West J (2006). "Recent advances in coeliac disease". Gut. 55 (7): 1037–46. doi:10.1136/gut.2005.075119. PMID 16766754.
- ^ "Coeliac UK - The charity for people with coeliac disease and dermatitis herpetiformis". Coeliac.co.uk. Retrieved 2009-05-18.
- ^ Fasano, A. "Prevalence of celiac disease in at-risk and not-at-risk groups in the United States: a large multicenter study". Arch Intern Med. 163 (3): 286–292. doi:10.1001/archinte.163.3.286. PMID 12578508.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ Presutti, John (2007-12-27). "Celiac Disease". American Family Physician. 76 (12): 196–1802.
{{cite journal}}: Unknown parameter|coauthors=ignored (|author=suggested) (help) - ^ Hill, I. D., Horvath, K., and Fasano, A., Epidemiology of celiac disease. 1: Am J Gastroenterol. 1995 Jan;90(1):163-4
- ^ "Wheat futures again hit new highs" article by Victoria Sizemore Long in The Kansas City Star September 28, 2007
- ^ "Wheat Prices Send Italian Pasta Costs Up" Associated Press story by Colleen Barry, September 13, 2007 By COLLEEN BARRY – Sep 13, 2007
- ^ "Broker picks in the soft commodities sector" in CompareShares April 2, 2008
- ^ http://faostat.fao.org/ FAOSTAT
- ^ "Major Food And Agricultural Commodities And Producers - Countries By Commodity". Fao.org. Retrieved 2009-05-18.
- ^ "G4319 Wheat Diseases in Missouri, MU Extension". Muextension.missouri.edu. Retrieved 2009-05-18.
- ^ List of Commodity Delivery Dates on Wikinvest
Further reading
- 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
- Christen, Olaf, ed. (2009), Winterweizen. Das Handbuch für Profis, DLG-Verlags-GmbH, ISBN 978-3-7690-0719-0
- 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
- S. Padulosi, K. Hammer, J. Heller, editors (1996). Hulled wheats. Promoting the conservation and use of underutilized and neglected crops. 4. International Plant Genetic Resources Institute, Rome, Italy.
{{cite book}}:|author=has generic name (help)CS1 maint: multiple names: authors list (link) - 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
External links
- Crop Wild Relatives Gap Analysis Portal reliable information source on where and what to conserve ex-situ, regarding Triticum genepool
- Price history of wheat, according to the IMF
- Photos of wheat fields
- Watch Australian science documentary on developing drought-resistant wheat
- Wheat Foods Council Est. 1972
- NAWG — Web site of the National Association of Wheat Growers
- CIMMYT — Web site of the International Maize and Wheat Improvement Center
- Triticum species at Purdue University
- A Workshop Report on Wheat Genome Sequencing
- Molecular Genetic Maps in Wild Emmer Wheat
- Winter Wheat in the Golden Belt of Kansas by James C. Malin, University of Kansas, 1944
- Varieties of club wheat hosted by the UNT Government Documents Department
- Triticum aestivum: facts, developmental stages, and inflorescence at GeoChemBio
- Major topic "Triticum": free full-text articles in National Library of Medicine
