Potential of ten wild diploid cotton species for the improvement of fiber fineness of upland cotton through interspecific hybridization

Cotton is the highest source of natural fiber in textile industry worldwide. With the modern spinning technologies, the demand for cotton fiber with higher quality has increased, making the genetic improvement of fiber quality one of the main challenges for cotton breeders. In cotton breeding, wild species are important source of several desirable genes for genetic improvement of the main cultivated cotton Gossypium hirsutum L (Upland cotton). Besides length and strength, fineness is one of the most important criteria associated with cotton fiber quality. In this study, ten wild diploid species of cotton were investigated for their fiber fineness and potential to improve fiber fineness of G. hirsutum L. The method was measuring of ribbon width after caustic swelling. The results showed the potential of four wild species (G. longicalyx Hutch. & Lee, G. anomalum Wawra & Peyr., G. thurberi Todaro and G. stocksii Mast.) to significantly improve the fiber fineness of upland cotton in a hybrid configuration. Among them, G. longicalyx stood out for its exceptional fiber fineness, and its remarkable impact on reducing the fiber fineness of G. hirsutum L. The wild species highlighted in this study constitute an interesting genetic resource for the development of upland cotton varieties with improved fiber fineness. Key words: Cotton, fiber fineness, Gossypium spp, hybrid, plant breeding, tetraploid species, wild diploid species.