Cotton (Gossypium spp.) is one of the most important economic crops in the world and also a major source of natural fiber, oil, and protein.The morphology of cotton species varies from trailing herbaceous perennials to trees ＜10 m.Like otherimportant crops, modern cotton cultivars are polyploids and have gone through polyploidization, evolution, and domestication.The cotton genus comprises approximately 45 diploid (2n=2x =26)and seven tetraploid species (2n =4x =52) (Guan et al., 2014).