Malvaceae

Gossypium barbadense

Gossypium is a genus of 39-40 species of shrubs in the mallow 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 3.0 m (9.8 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 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. 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. Most wild cottons are diploid, but there is a group of five species from America and Pacific islands which are tetraploid, apprently due a single hybridization 0.5 to 2 million years ago.[2] The tetraploid species are G. hirsutum, G. tomentosum, G. mustelinum, G. barbadense, and G. darwinii.