Difference between revisions of "Gossypium"
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Revision as of 12:11, 20 October 2007
- For information on cotton production, industry, history, and applications, see cotton.
- For the clothing company, see Gossypium (clothes).
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 Gossypium barbadense | ||||||||||||
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Gossypium is a genus of 39-40 species of shrubs in the family Malvaceae, native to the tropical and subtropical regions of both the Old World and the New World. The cotton plants, sources of commercial cotton fabric, are included in this genus.
Cotton shrubs can grow up to 3 m (10 ft) high. 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 downy fibres called lint. Commercial species of cotton plant are G. hirsutum (90% of world production), G. barbadense (8%), G. arboreum and G. herbaceum (together, 2%). While the lint (fiber) naturally occurs in colors of white, brown, and green, fears of contaminating the genetics of white cotton has led many cotton-growing locations to ban growing of coloured cotton varieties.
Species of Gossypium
- Commercial cotton species
Commercial cotton fibres, used to manufacture cloth, are derived from the fruit of the cotton plant. The following species are grown commercially:
- Gossypium arboreum L. – Tree cotton, native to India and Pakistan.
- Gossypium barbadense L. – known as American Pima, Creole, Egyptian, or Sea island cotton, native to tropical South America.
- Gossypium herbaceum L. – Levant cotton, native to southern Africa and Arabian Peninsula.
- Gossypium hirsutum L. – Upland cotton, native to Central America, Mexico, the Caribbean and southern Florida - most commonly grown species in the world.
- Non-commercial species
- Gossypium australe F.Muell – Endemic to north-western Australia
- Gossypium darwinii - Darwin's cotton, found only on the Galapagos Islands
- Gossypium sturtianum J.H. Willis – Sturt's Desert Rose, native to Australia.
- Gossypium thurberi Tod. – Arizona wild cotton, native to Arizona and northern Mexico.
- Gossypium tomentosum Nutt. ex Seem – Ma‘o or Hawaiian cotton, endemic to the Hawaiian Islands.
Many varieties of cotton have been developed by selective breeding and hybridization of the above species. Experiments are ongoing to cross-breed various desirable traits of wild cotton species into the principal commercial species, such as resistance to insects, disease and drought-tolerance.
Cotton pests and diseases
Pests
- Boll weevil, Anthonomus grandis
- Cotton aphid, Aphis gossypii
- Cotton stainer, Dysdercus Koenigii
- Cotton bollworm, Helicoverpa armigera and native budworm Helicoverpa punctigera are caterpillars that damage cotton crops.
- Some other Lepidoptera larvae also feed on cotton - see list of Lepidoptera which feed on Cotton plants.
- Green mirid (Creontiades dilutus), a sucking insect
- Spider mites, Tetranychus urticae, T. ludeni and T. lambi
- Thrips, Thrips tabaci and Frankliniella schultzei
Diseases
- Alternaria leaf spot, caused by Alternaria macrospora and Alternaria alternata
- Anthracnose boll rot, caused by Colletotrichum gossypii
- Black root rot, caused by the fungus Thielaviopsis basicola
- Blight caused by Xanthomonas campestris pv. malvacearum
- Fusarium boll rot caused by Fusarium spp.
- Phytophthora boll rot, caused by Phytophthora nicotianae var. parasitica
- Sclerotinia boll rot, caused by fungus Sclerotinia sclerotiorum
- Stigmatomycosis, caused by the fungi Ashbya gossypii, Eremothecium coryli (Nematospora coryli) and Aureobasidium pullulans
See also
External links
Gossypium hirsutum flower with bumblebee pollinator, Hemingway, South Carolina
Gossypium tomentosum boll
Integrated Pest Management bollworm trap at a cotton field in Manning, South Carolina
Natural biocontrol: Predatory Polistes wasp looking for bollworms or other caterpillars on cotton plant in Hemingway, South Carolina
