Description and technical features of cotton fiber

Cotton is a natural fibre of vegetable origin, like linen, jute or hemp. Mostly composed of cellulose (a carbohydrate plant substance) and formed by twisted, ribbon-like shaped fibres, cotton is the fruit of a shrubby plant commonly referred to as the "cotton plant". The cotton plant, a variety of plants of the genus Gossypium, belongs to the Malvacae family, which comprises approximately 1,500 species, also including the baobab tree, the bombax or the mallow. The plant, growing up to 10 metres high in the wild, has been domesticated to range between 1 to 2 metres under commercial cultivation in order to facilitate picking. Either herbaceous or ligneous, it thrives in dry tropical and subtropical areas. Whereas by nature the plant is a perennial tree (lasting about 10 years), under extensive cultivation it is mostly grown as an annual shrub. The cotton flower has five large petals (showy, white, white-creamy, or even rose in colour), which soon fall off, leaving capsules, or "cotton bolls", having a thick and rigid external layer. The capsule bursts open upon maturity, revealing the seeds and masses of white/creamy and downy fibres. Cotton fibres of the Gossypium hirsutum species range from about 2 to 3 centimetres in length, whereas Gossypium barbadense cotton produces long-staple fibres up to 5 centimetres length. Their surface is finely indented, and they become kinked together and interlocked. The cotton plant is almost exclusively cultivated for its oleaginous seeds and for the seminal fibres growing from them (i.e. cotton, strictly speaking). In ordinary usage, the term "cotton" also makes reference to fibres that are made into fabric wires suitable for use in the textile industry.
Although the cotton plant is native to tropical countries, cotton production is not limited to the tropics. Indeed, the emergence of new varieties, as well as advances in cultivation techniques led to the exapansion of its culture within an area straddling from approximately 47 degrees North latitude (Ukraine) to 32 degrees South (Australia). Although cotton is widely planted in both hemispheres, it remains a sun-loving plant highly vulnerable to freezing temperatures. Cotton is crucially important to several developing countries. Out of the 65 cotton-producing countries in 2007/08, 52 were developing countries, 21 of which were indexed by the United Nations among the least developed countries (LDCs).

Cotton-growing countries by geographical area, 2005

	Developed countries	Developing countries			Total
		LDCs	Transition	Other
Africa		18		9	27
North and Central America	1			1	2
South America				8	8
Caribbean				1	1
Asia	1	3	6	12	22
Europe	3		1		4
Oceania	1				1
Total	6	21	7	31	65

Cotton is of utmost importance to developing countries, particularly in West and Central Africa, where around 10 million people depend on the sector for their revenues. Besides being a major natural fibre crop, cotton also provides edible oil and seed by-products for livestock food. Cottonseed oil is a vegetable oil ranking fifth in world use among edible oils (accounting for about 4% of world consumption of vegetable oil). The cottonseed meal is usually used as roughage in the diet of cattle for its high proteinic and energetic value.
On about fifty species of cotton plants within the world only four are domestically cultivated for their fibres. The most commonly cultivated species of cotton in the world include Gossypium hirsutum and Gossypium barbadense (also referred to as "New World" species). Gossypium hirsutum originated in Mexico. It is the most important agricultural cotton, accounting for more than 90% of world fibre production. Gossypium barbadense, of Peruvian origin, accounts for about 5% of world fibre. It includes cotton fibres of the highest quality, such as the Jumel variety (from the Barbados), among the finest cotton in terms of quality and fibre length. Two additional cultivated species are Gossypium arboreum (which originated in the Indo-Pakistan subcontinent) and Gossypium herbaceum (from southern Africa), which are also called "Old World" or "Asiatic cottons". These two varieties of cotton with short staple-length fibre have no commercial value per se (only 5% of world production alltogether). However, several varieties that are grown on a commercial scale botanically derive therefrom.

Cottonseed composition

	Whole seed	Oilmeal (deoiled and partially peeled)	Oilcake expeller (partially peeled)	Hull
Dry matter (%)	92	90	93	92
Proteins (%) MS	22 (19-25)	42 (35-53)	40 (28-49)	5 (3-7)
Rough cellulose (%) MS	28 (23-37)	18 (11-23)	15 (11-23)	53 (49-62)
Fatty matter (%) MS	20 (10-28)	3 (0,4-6)	7 (4-11)	3 (0,6-5)
Ashes (%) MS	4	7	7	3
Calcium (%) MS	0,2	0,3	0,2	0,15
Phosphorus (%) MS	0,6	1,3	1,2	0,19