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
The earliest known evidence of human use of G. barbadense has been along the coast of present-day Ecuador and Peru. It is plausible humans in that area were also the first to domesticate the species. However, available evidence, such as seeds found in the floors of ancient houses, could be the result of either cultivated or wild-gathered cotton. So far, archaeologists have found evidence of widespread use in this region about 5000 years ago. Further, they have strong evidence at a few sites dating back 5500 years, and weaker evidence as far back as 7800 years. Investigators at one of the circa 5500 year-old sites, in the Ñachoc valley in northern Peru, argue that domestication did not happen there, therefore G. barbasense was domesticated elsewhere and then brought to Ñachoc.
By 1000 BCE, Peruvian cotton bolls were indistinguishable from modern cultivars of G. barbadense. Native Americans grew cotton widely throughout South America and in the West Indies, where Christopher Columbus encountered it. At the time of Columbus, indigenous peoples of the West Indies raised G. barbadense as a dooryard crop, single plants near residences.
The advent of worldwide trade resulted in many kinds of plants being introduced to new places (see Columbian exchange). In the case of cotton, this exchange happened in all directions, new world cottons to the old world, old world cottons to the new world, and cottons to places which they had never grown before. In some cases, this resulted in multiple kinds of cotton growing in the same region. Since then, most of these regions have transitioned to specialize in a particular kind of cotton, resulting in the distinctive market classes of today.
During the 17th century, European colonists in the English West Indies developed cotton as a cash crop for export to Europe, establishing numerous plantations operated by white indentured servants and Black slaves to do so. By the 1650s, Barbados had become the first English colony in the West Indies to export cotton to Europe. By the late 1700s and early 1800s, G. barbadense was a major commercial crop in the West Indies. After the early 19th century, it was mostly supplanted as a cash crop by sugar cane. There have been a few periods since the early 1800s when cotton production has been attractive in the West Indies, but generally sugar cane has been more profitable.
Classification by staple length Cotton traders use many systems to classify the quality of cotton fiber. One of the most significant distinctions is "staple length", length of the individual fibers. Traditionally, cultivars of Gossypium barbadense fall into the "long-staple" category. The term extra-long-staple (ELS) first came into use in 1907. The International Cotton Advisory Committee, in an attempt to standardize classification, defined extra-long-staple as or longer, and long-staple as . Under this classification scheme, most cultivars of G. barbadense produce extra-long-staple fibers, but some cultivars qualify as long-staple.
Cultivation The species accounts for about 5% of the world's cotton production. Certain regions specialize in G. barbadense. One reason is to prevent different species of cotton from hybridizing with each other. If a field of G. barbadense is too close to a field of a different species, the result is generally poor quality of the fiber.
In historical times, G. barbadense was mostly a dooryard crop and treated as a perennial. Individual households would maintain one or a few bushes for years at a time. This form of cultivation continues to a small extent to the present. However, nearly all cotton production, G. barbadense or otherwise, are now row crops and treated as an annual. Plants are grown from seed each year.
G. barbadense organized by market class Traders in cotton have developed several broad categories called market classes. These categories are based on the characteristics of the fiber and the region where they are produced. In the United States, some market classes have been formalized in law.
Sea Island cotton Sea Island is a historical market class. It was actively marketed from 1790 to 1920. It was grown on the Sea Islands, islands off the coast of South Carolina, Georgia, and Florida. It once was an important market class. In the markets of Europe, it suffered little competition from cottons with similar characteristics from its inception until the interruption of trade resulting from the U.S. Civil War.
Origins of Sea Island The origins of Sea Island cotton has been the subject of considerable controversy. Nevertheless, developing the market class required developing cultivars that would be productive in the Sea Islands, and developing a product that was distinct from other kinds of cotton. It also required at least some producers and consumers to agree "Sea Island" was a useful category.
One of the challenges explaining the development of a long fiber cotton that would thrive in the Sea Islands is that the cotton in the Sea Islands came from the West Indies, an area where all the cultivated cotton was short fiber (by today's standards) and required a long growing season. A distinctive cotton could not be developed in the Sea Islands, at least not by the methods of hybridization or selection, because frost killed the plants before they had a chance to produce seed.