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''Gossypium'' is the cotton genus. It belongs to the tribe ''Gossypieae'', in the mallow family, Malvaceae, native to the tropical and subtropical regions from both the Old and New World. The genus ''Gossypium'' comprises around 50 species,〔Jonathan F. Wendel, Curt Brubaker, Ines Alvarez, Richard Cronn and James McD. Stewart. 2009. Evolution and Natural History of the Cotton Genus. In Andrew H. Paterson (Ed.). Genetics and Genomics of Cotton. Plant Genetics and Genomics: Crops and Models, 2009, Volume 3, 3-22.〕 making it the largest in species number in the tribe ''Gossypioieae''. New species continue to be discovered.〔 The name of the genus is derived from the Arabic word ''goz'', which refers to a soft substance. Cotton is the primary natural fibre used by modern humans. Cultivated cotton is also a major oilseed crop, as well as a main protein source for animal feed. Cotton plants thus have an enormous weight in the world economy and are of great importance for the agriculture, industry and trade of many tropical and subtropical countries in Africa, South America and Asia. Consequently, the genus ''Gossypium'' has long attracted the attention of scientists. The origin of the genus ''Gossypium'' is dated to around 5-10 million years ago.〔David S. Senchina, Ines Alvarez, Richard C. Cronn, Bao Liu, Junkang Rong, Richard D. Noyes, Andrew H. Paterson, Rod A. Wing, Thea A. Wilkins and Jonathan F. Wendel. 2003. Rate Variation Among Nuclear Genes and the Age of Polyploidy in Gossypium. Mol. Biol. Evol. 20(4):633–643.〕 ''Gossypium'' species are distributed in arid to semiarid regions of the tropics and subtropics. Generally shrubs or shrub-like plants, the species of this genus are extraordinarily diverse in morphology and adaptation, ranging from fire-adapted, herbaceous perennials in Australia to trees in Mexico.〔 Cultivated cottons are perennial shrubs most often grown as annuals. Plants are 1–2 m high in modern cropping systems, sometimes higher in traditional, multiannual cropping systems, now largely disappearing. The leaves are broad and lobed, with three to five (or rarely seven) lobes. The seeds are contained in a capsule called a "boll", each seed surrounded by fibres of two types. These fibres are the more commercially interesting part of the plant and they are separated from the seed by a process called ginning. At the first ginning, the longer fibres, called staples, are removed and these are twisted together to form yarn for making thread and weaving into high quality textiles. At the second ginning, the shorter fibres, called "linters", are removed, and these are woven into lower quality textiles (which include the eponymous Lint). Commercial species of cotton plant are ''G. hirsutum'' (>90% of world production), ''G. barbadense'' (3-4%), ''G. arboreum'' and ''G. herbaceum'' (together, 2%). Many varieties of cotton have been developed by selective breeding and hybridization of these species. Experiments are ongoing to cross-breed various desirable traits of wild cotton species into the principal commercial species, such as resistance to insects and diseases, and drought tolerance. Cotton fibres occur naturally in colours of white, brown, green, and some mixing of these. Most wild cottons are diploid, but a group of five species from America and Pacific islands are tetraploid, apparently due to a single hybridization event around 1.5 to 2 million years ago.〔 The tetraploid species are ''G. hirsutum'', ''G. tomentosum'', ''G. mustelinum'', ''G. barbadense'', and ''G. darwinii''. ==Selected species== ;Subgenus ''Gossypium'' *''Gossypium arboreum'' L. – tree cotton (India and Pakistan) *''Gossypium herbaceum'' L. – Levant cotton (southern Africa and the Arabian Peninsula) ;Subgenus ''Houzingenia'' *''Gossypium raimondii'' Ulbr. – one of the putative progenitor species of tetraploid cotton, alongside ''G. arboreum'' *''Gossypium thurberi'' Tod. – Arizona wild cotton (Arizona and northern Mexico) ;Subgenus ''Karpas'' *''Gossypium barbadense'' L. – Creole cotton (tropical South America) *''Gossypium darwinii'' G.Watt – Darwin's cotton (Galápagos Islands) *''Gossypium hirsutum'' L. – upland cotton (Central America, Mexico, the Caribbean and southern Florida) *''Gossypium mustelinum'' Miers ex G.Watt *''Gossypium tomentosum'' Nutt. ex Seem – ''Mao'' or Hawaiian cotton (Hawaii) ;Subgenus ''Sturtia'' *''Gossypium australe'' F.Muell (northwestern Australia) *''Gossypium sturtianum'' J.H. Willis – Sturt's desert rose (Australia) 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Gossypium」の詳細全文を読む スポンサード リンク
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