Gossypium

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For information on cotton production, industry, history, and applications, see cotton.

Gossypium
Gossypium barbadense
Scientific classification
Kingdom: Plantae Division: Magnoliophyta Class: Magnoliopsida Order: Malvales Family: Malvaceae Genus: Gossypium L.
Species
See text.

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 of two types. These fibres are the commercially interesting part of the plant and they are removed 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 including the eponymous Lint. Commercial species of cotton plant are G. hirsutum (90% of world production), G. barbadense (8%), G. arboreum and G. herbaceum (together, 2%). While cotton fibers occur naturally 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.
• Gossypium raimondii one of the putative progenitor species of tetraploid cotton alongside Gossypium arboreum.

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

Cotton field in Sukhumi botanical garden, photo ca. 1912

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 (butterfly and moth) larvae also feed on cotton - see list of Lepidoptera that 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

See also: List of cotton 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

• Cotton

External links

Wikimedia Commons has media related to:

Gossypium

• Central Institute for Cotton Research (India)

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