| As the leading natural fiber source, cotton has been playing the important role in the world. With the advances in spinning technology and the needs of the people, the better fiber quality will be required. These requirements of fiber quality have attracted a lot of efforts of governments and scientists to improve cotton fiber quality, especially that of upland cotton.Conventional genetic strategies have been employed to enhance the fiber properties of upland cotton for over half a century. However, the improvement of fiber quality was hindered by several factors,These factors greatly limited the efficiency of conventional breeding efforts in cotton, and it is imperative to develop effective cotton breeding approaches. Recent advances in DNA markers offer plant breeders a rapid and precise alternative approach to conventional selection schemes to improve quantitative traits. Using detailed molecular linkage maps, quantitative trait loci (QTL) affecting economically important traits could be mapped, genetically evaluated and selected through linked markers, and even cloned and transformed into target plants. In upland cotton, the genetic linkage maps have been developed and used to identify QTL for agronomic and fiber quality traits. In this study, a genetic linkage map was constructed with SSR markers using 178 F2 plants developed from a cross between upland cotton cultivar xinluzao24 and Sk5. The present genetic linkage map was used to identify and map the quantitative trait loci (QTL) affecting fiber-related traits in F2:3 family lines. The mainly results were as following:1. The two mapping parents, xinluzao 24 and SK5, were markedly different in fiber-related traits and have the complementary traits, F2:3 family of fiber-related traits with multiple genes to the genetic characteristics, lint, micronaire value was extremely isolated. Lint and the first half of the average length uniformity negatively correlated with micronaire, fracture strength, Elongation between correlated, but the correlation was not significant.2. A total of 50 polymorphism primer pairs were found among a total of 2100 cotton SSR primer pairs and a total of 50 loci were employed to perform linkage analysis using the intraspecific population (xinluzao 24×SK5)F2 of upland cotton. 34 markers were distributed into 12 linkage groups, while 16 markers remained unlinked. The linkage map covered 615.9 cM or approximately 12.32% of the total recombination length of the cotton genome. The linkage groups with the average distance about 18.11 cM between two markers.3. Based on composite interval mapping, one QTL was identified for lint percent, explaining 76.93% of the lint percent variance. One QTL for fiber strength were identified, explaining 30.82% of the fiber strength variance. One QTL for Micronaire were identified, explaining 13.57% of the Micronaire variance. One QTL for fiber boll weight were identified, explaining 50.03% of the boll weight variance. Two QTL for Flowering were identified, explaining 56.32-56.33% of the Flowering variance. |
