Gossypium barbadense is one of several species of cotton. It is in the mallow family. It has been cultivated since antiquity, but has been especially prized since a form with particularly long fibers was developed in the 19th century. Other names associated with this species include Sea Island, Egyptian, Pima, and extra-long staple (ELS) cotton. The species is a tropical, frost-sensitive perennial that produces yellow flowers and has black seeds. It grows as a bush or small tree and yields cotton with unusually long, silky fibers. The native range of this species is Colombia to Peru. It is now cultivated in dry tropical and arid subtropical areas around the world. It is the major source of the longer grades of cotton, but accounts for only a small proportion of the overall cotton market.
Taxonomy and etymology Linnaeus is given credit for describing Gossypium barbadense ("the cotton encountered in Barbados"). Today, this name is universally accepted; however, there is some question whether the modern definition matches what Linnaeus described. Paul A. Fryxell argues, although the evidence surviving from Linnaeus's time is less than ideal, the name is applied correctly. On the other hand, Y. I. Prokhanov and G. K. Brizicky argue that Linnaeus never actually saw any examples of the species we now call G. barbadense. The species is a member of the mallow family, Malvaceae. Authors differ on the ranks between family and genus. A recent example that considers cladistics is Bayer et al. (1999). In this system, G. barbadense and other cottons fall in the subfamily Malvoideae and tribe Gossypiae. The tribe Gossypiae includes cotton species and others that produce the substance gossypol. The genus Gossypium encompasses the cottons. The genus can be divided by chromosome count. Subgenus Karpas has 52 chromosomes (four sets of 13). This subgenus encompasses G. barbadense, along with G. hirsutum and a few other New World cottons. In comparison, the commercially important Old World cottons have 26 chromosomes. Most botanists who study Gossypium believe that the group of cottons with 52 chromosomes forms a clade. In other words, G. barbadense, G. hirsutum, and a few other New World cotton species arose from the same ancestor. One form of G. barbadense has been recognized as a variety. Var brasiliense is called "kidney seed cotton" because its seeds are fused together into somewhat kidney-shaped masses.
Description G. barbadense, like other cottons, forms a small bush in its first year. In cultivation, it is treated as an annual. If allowed to, it can grow into a large bush or even a small tree of height 1–3 m. Leaves are mostly 8–20 cm long, with 3-7 lobes. One distinction between G. barbadense and the more commonly cultivated G. hirsutum is that G. barbadense has three to five lobes whereas G. hirsutum has only three. The lobes of G. barbadense's are also more deeply cut, about two-thirds the length of the leaf, as opposed to one half for G. hirsutum. Cotton flowers are showy, with five petals that open only partially. The petals are up to 8 cm long, usually yellow. The petals of Sea Island cultivars typically are creamy yellow with a red spot at the base, and as they wither, they turn rose pink. Like other members of the mallow family, the flowers have many stamens, which are merged to form a cylinder around the style. The seeds and fiber form in a capsule called a "bole". Each bole is divided into three parts, each of which produce 5-8 seeds. The seeds are 8-10 mm long. Thousands of years of cultivation have dramatically changed the fiber in cotton plants. Wild cottons have very little fiber, so little it might not be noticed. The fiber emanates from each seed. The purpose of the fiber to wild plants is unknown. Domesticated cottons have much more fiber. Besides the more obvious long fibers, domesticated cotton seeds have short fibers called "linters". Some cultivars of G. barbadense have so few of these short hairs they are often called "lintless". They can also be called "smooth-seeded" as opposed to "fuzzy-seeded" G. hirsutum. As with all cottons, the bolls open when they mature, revealing showy "snowballs" of fiber. All cottons contain gossypol, although some cultivars of G. hirsutum have been selected to minimize this chemical. Those cultivars are more susceptible to insect pests, which suggests the natural purpose of gossypol is to deter pests. The impact of gossypol in agriculture is it makes cotton plants poisonous to non-ruminant animals.
Distribution and habitat G. barbadense grows in dry portions of the tropics, where it is a perennial. Treated as an annual, and with the benefit of irrigation, it can be cultivated quite successfully in arid subtropical regions. Human activity has substantially expanded the range of the species. Today, wild populations exhibit the most genetic diversity in Ecuador and Peru, and based on this, Percy and Wendel argue that region is where the species originated (see Vavilov center). S.G. Stephens and M.E. Mosely narrowed this to a small area near the Guayas Estuary in Ecuador and an island off of Manta, Ecuador, as that is where the forms with the most wild characteristics are found. From there, it dispersed. Its natural range is dry habitats from the western South American coast to the intermontaine valleys of the northern Andes to riverine northern South America. By the time Columbus encountered it being cultivated in the Caribbean, its range included much of tropical South and Central America. G. barbadense is now cultivated around the world, including China, Egypt, Sudan, India, Australia, Peru, Israel, the southwestern United States, Tajikistan, Turkmenistan, and Uzbekistan.
History
… excerpt ends here. Continue reading the full article.
