- Published on Saturday, 31 January 2015 10:06
- Hits: 715
Cotton is the most popular fabric in the world and is grown in 85 countries according to UNCTAD, of which 80 were developing countries.
Biology of Cotton
The processed cotton fibre consists of nearly pure cellulose and is produced from plants of the genus Gossypium of the mallow family, Malvacae. The cotton plant produces large showy, white, creamy or yellow flowers that fall off to leave a large capsule, or cotton boll that contains both the seeds and a mass of white, downy cotton fibre.
There are about 43 species of Gossypium but only 4 are important for cultivation, that is, two species of Old World Cottons from Africa and Asia and two New World Cottons of the Americas. Both groups have been cultivated for a long time and cotton has been used to make fine lightweight textiles in areas with tropical climates for thousands of years.
History of Cotton
The genus Gossypium probably originated in Africa 150 million years ago (cf. Charrier). The splitting up of Gondwanaland and the separation and formation of the present continents then caused the separation and subsequent development of the different Old and New World cotton species and varieties.
Cotton has been found in Mexican caves (Tehaucan valley) dating back to about 3500 BC and there is archaeological evidence from the Indus valley (MohenjoDaro) of Pakistan from 2700 BC and from Peru in 2500 BC (Stephens, 1970 in Charrier). These three sites are likely to have been original centres of cotton cultivation.
Cotton cultivation in the Old World began from India and Pakistan, where cotton may have been grown for more than 6,000 years and was gradually exported to Mesopotamia, Egypt and surrounding countries. The Greek historian Herodotus wrote of cotton in India in 440 BC, “There, too, wool more beautiful and excellent than the wool of sheep grows on wild trees; these trees supply the Indians with clothing” (The Histories Book 3. CVI).
Cotton was adopted much more slowly into Europe, but during the late medieval period, cotton became a commonly imported fibre to northern Europe. Most Europeans did not know how it was derived, except that it was a plant. John Mandeville, writing in 1371, stated that, "In that land [India] be trees that bear wool, as though it were of sheep, whereof men make clothes and all things that may be made of wool”. Mandeville’s book has been credited with claiming that the plants bore lambs at the tips of their branches, although this was probably a later elaboration (in some versions of the book) long after Mandeville’s death.
Buy cotton bolls
By the end of the 16th century, cotton was cultivated throughout the warmer regions of Asia and the Americas.
Types of Cotton
The four principal species of cotton are;
Old World Cottons
1. Gossypiumherbaceum in Africa and Asia, includes the most primitive cultivated forms of Old World cotton).
2. Gossypiumarboreum – tree cotton native to India and Pakistan and probably found in cultivation only.
New World Cottons
3. Gossypiumbarbadense includes American Pima, Creole, ‘Sea Island’ and Egyptian cottons and is native to tropical South America. It produces a high quality, long staple cotton with fibres of up to 5 cm in length and accounts for 8% of commercial cotton production.
4. Gossypiumhirsutum or ‘Upland’ cotton is believed to have evolved in Mexico and is native to Central America, Mexico and the Caribbean. It produces much shorter fibres of 2 to 3 cm in length but is the most commonly grown cotton and accounts for 90% of the world’s commercial production of cotton fibre.
The cotton plant is also a source of cottonseed, which is pressed for oil that is used in salad oils, cosmetics, soap, candles, detergents, and paint, and cottonseed hulls and meal are used for animal feed.