Common wheat

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Common wheat
Blé tendre (GRAPELLI) AO-5-cliche Jean Weber (5) (23975019962).jpg
Ears of common wheat
Scientific classification edit
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Clade: Commelinids
Order: Poales
Family: Poaceae
Subfamily: Pooideae
Genus: Triticum
Species:
T. aestivum
Binomial name
Triticum aestivum
Synonyms
  • Triticum sativum Lam.
  • Triticum vulgare Vill.
Triticum aestivum subsp. aestivum - MHNT

Common wheat (Triticum aestivum), also known as bread wheat, is a cultivated wheat species.[1][2][3][4][5] About 95% of wheat produced worldwide is common wheat;[6] it is the most widely grown of all crops and the cereal with the highest monetary yield.[7]

Nomenclature and taxonomy of wheat and its cultivars[edit]

Numerous forms of wheat have evolved under human selection. This diversity has led to confusion in the naming of wheats, with names based on both genetic and morphological characteristics. For more information, see the taxonomy of wheat.

List of the common cultivars[edit]

Evolution[edit]

Bread wheat is an allohexaploid (an allopolyploid with six sets of chromosomes: two sets from each of three different species). Of the six sets of chromosomes, two come from Triticum urartu (einkorn wheat) and two from Aegilops speltoides. This spontaneous hybridisation created the tetraploid species Triticum turgidum (emmer wheat) 580,000–820,000 years ago. The last two sets of chromosomes came from wild goat-grass Aegilops tauschii 230,000–430,000 years ago.[6][9] Recent research suggest that T. macha originated from a hybrid cross between T. aestivum and wild emmer wheat.[10][11]

Free-threshing wheat is closely related to spelt. As with spelt, genes contributed from Aegilops tauschii give bread wheat greater cold hardiness than most wheats, and it is cultivated throughout the world's temperate regions.[citation needed]

History[edit]

Common wheat was first domesticated in Western Asia during the early Holocene, and spread from there to North Africa, Europe and East Asia in the prehistoric period.[citation needed] Naked wheats (including Triticum aestivum/durum/turgidum) were found in Roman burial sites ranging from 100BCE to 300CE .[12]

Wheat first reached North America with Spanish missions in the 16th century, but North America's role as a major exporter of grain dates from the colonization of the prairies in the 1870s. As grain exports from Russia ceased in the First World War, grain production in Kansas doubled.[citation needed]

Worldwide, bread wheat has proved well adapted to modern industrial baking, and has displaced many of the other wheat, barley, and rye species that were once commonly used for bread making, particularly in Europe.[citation needed]

Plant breeding[edit]

A field of wheat in Deggendorf, Germany

Modern wheat varieties have been selected for short stems, the result of RHt dwarfing genes[13] that reduce the plant's sensitivity to gibberellic acid, a plant hormone that lengthens cells. RHt genes were introduced to modern wheat varieties in the 1960s by Norman Borlaug from Norin 10 cultivars of wheat grown in Japan. Short stems are important because the application of high levels of chemical fertilizers would otherwise cause the stems to grow too high, resulting in lodging (collapse of the stems). Stem heights are also even, which is important for modern harvesting techniques.[citation needed]

Other forms of common wheat[edit]

Ears of compact wheat

Compact wheats (e.g., club wheat Triticum compactum, but in India T. sphaerococcum) are closely related to common wheat, but have a much more compact ear. Their shorter rachis segments lead to spikelets packed closer together. Compact wheats are often regarded as subspecies rather than species in their own right (thus T. aestivum subsp. compactum).[citation needed]

See also[edit]

References[edit]

  1. ^ Brenchley, R; Spannagl, M.; Pfeifer, M.; Barker, G. L.; d'Amore, R.; Allen, A. M.; McKenzie, N.; Kramer, M.; Kerhornou, A.; Bolser, D.; Kay, S.; Waite, D.; Trick, M.; Bancroft, I.; Gu, Y.; Huo, N.; Luo, M. C.; Sehgal, S.; Gill, B.; Kianian, S.; Anderson, O.; Kersey, P.; Dvorak, J.; McCombie, W. R.; Hall, A.; Mayer, K. F.; Edwards, K. J.; Bevan, M. W.; Hall, N. (2012). "Analysis of the bread wheat genome using whole-genome shotgun sequencing". Nature. 491 (7426): 705–10. Bibcode:2012Natur.491..705B. doi:10.1038/nature11650. PMC 3510651. PMID 23192148.
  2. ^ Bonjean, Alain P. and William J. Angus (eds) (2001). The world wheat book : a history of wheat breeding. Andover: Intercept. p. 1131. ISBN 978-1-898298-72-4.CS1 maint: extra text: authors list (link) Excellent resource for 20th century plant breeding.
  3. ^ Caligari, P.D.S. and P.E. Brandham (eds) (2001). Wheat taxonomy : the legacy of John Percival. London: Linnean Society, Linnean Special Issue 3. p. 190.CS1 maint: extra text: authors list (link)
  4. ^ Heyne, E.G. (ed.) (1987). Wheat and wheat improvement. Madison, Wis.: American Society of Agronomy. p. 765. ISBN 978-0-89118-091-3.CS1 maint: extra text: authors list (link)
  5. ^ Zohary, Daniel and Maria Hopf (2000). Domestication of Old World plants: the origin and spread of cultivated plants in West Asia. Oxford: Oxford University Press. p. 316. ISBN 978-0-19-850356-9. Standard reference for evolution and early history.
  6. ^ a b Mayer, K. F. X. (2014). "A chromosome-based draft sequence of the hexaploid bread wheat (Triticum aestivum) genome". Science. 345 (6194): 1251788. doi:10.1126/science.1251788. PMID 25035500. S2CID 206555738.
  7. ^ "Triticum aestivum (bread wheat)". Kew Gardens. Retrieved 1 October 2016.
  8. ^ a b Sanità Di Toppi, L.; Castagna, A.; Andreozzi, E.; Careri, M.; Predieri, G.; Vurro, E.; Ranieri, A. (2009). "Occurrence of different inter-varietal and inter-organ defence strategies towards supra-optimal zinc concentrations in two cultivars of Triticum aestivum L". Environmental and Experimental Botany. 66 (2): 220. doi:10.1016/j.envexpbot.2009.02.008.
  9. ^ Marcussen, T. (2014). "Ancient hybridizations among the ancestral genomes of bread wheat". Science. 345 (6194): 1250092. doi:10.1126/science.1250092. PMID 25035499. S2CID 206554636.
  10. ^ De Oliveira, Romain; Rimbert, Hélène; Balfourier, François; Kitt, Jonathan; Dynomant, Emeric; Vrána, Jan; Doležel, Jaroslav; Cattonaro, Federica; Paux, Etienne; Choulet, Frédéric (18 August 2020). "Structural Variations Affecting Genes and Transposable Elements of Chromosome 3B in Wheats". Frontiers in Genetics. 11: 891. doi:10.3389/fgene.2020.00891. PMC 7461782. PMID 33014014.
  11. ^ Matsuoka, Yoshihiro (1 May 2011). "Evolution of Polyploid Triticum Wheats under Cultivation: The Role of Domestication, Natural Hybridization and Allopolyploid Speciation in their Diversification". Plant and Cell Physiology. 52 (5): 750–764. doi:10.1093/pcp/pcr018. PMID 21317146.
  12. ^ Rottoli, Mauro; Castiglioni, Elisabetta (19 April 2011). "Plant offerings from Roman cremations in northern Italy: a review". Vegetation History and Archaeobotany. 20 (5): 495–506. doi:10.1007/s00334-011-0293-3. ISSN 0939-6314. S2CID 128545750.
  13. ^ m., E.; w., S.; k., G.; g., R.; r., R. (2002). ""Perfect" markers for the Rht-B1b and Rht-D1b dwarfing genes in wheat". Theoretical and Applied Genetics. 105 (6–7): 1038–1042. doi:10.1007/s00122-002-1048-4. PMID 12582931. S2CID 22854512.