Generally cotton refers to four species of the genus Gossypium L. apparently domesticated
independently in four separate regions, in both the Old World and the New World (Sauer, 1993; Brubaker et al., 1999c). The word is derived from the Arabic “quotn”, “kutum” or “gutum” and refers to the crop that produces spinnable fibres on the seed coat (Lee, 1984; Smith, 1995). Gossypium (cotton) comprises approximately 50 species worldwide in the arid to semi-arid tropics and subtropics (Fryxell, 1992; Wendel and Cronn, 2003).