Association Analysis Of Yield And Fiber Quality Traits In Upland Cotton (Gossypium Hirsutum L.) With SSR Markers

Cotton is an important natural fibre crop in China. Development of varieties with high yield and good fiber quality is an important target in cotton breeding program. Identification of linked molecular markers for subsequent marker assisted breeding is essential to improve breeding efficiency especially for yield and fiber quality, which were controlled by multigene.Based on SSR technique and phenotypic data of two years, association analysis between yield and fiber quality and SSR marker was performed in Gossypium hirsutum L. The main results were as follows:1. Statistical analysis indicated that most of the yield and fiber quality traits showed relatively high variance coefficient from 0.89% to 23.59%, with average of 7.45%, indicating relative high phenotypice diversity in the materials tested.2. Genetic diversity analysis showed that a total of 841 alleles were obtained in the 209 materials from 218 polymorphic SSR primers. Each primer detected 3.86 alleles. The average Genetic Diversity Content(GDC) was 0.45. Polymorphism information content(PIC) of primers ranged from 0.02 to 0.75, with an average of 0.38. These results indicated that there are high genetic diversity in the genotypes tested, which is agree with the phenotypic data results.3. Population structure was analyzed with STRUCTURE 2.3.1software. The 209varieties/lines were divided into 3 subgroups(POP-1、POP-2 and POP-3) with 44、72 and 93 genotypes, respectively. Cluster analysis based on Nei’s genetic distance divided the 209 upland cotton cultivars/ lines into three subgroups.4. Association analysis using GLM was performed. A total of 167 loci were detected, of which 64 loci were related to yield related traits, and 103 loci were related to fiber quality traits. Among them, 45 SSR loci significantly associated with two or more traits simultaneously, which might be the results of genetic linkage or pleiotropic effect.5. The phenotypic effect values of associated SSR markers were calculated. Many elite alleles for yield and fiber quality and their carrier materials were identified. Results of this work will provide useful tool and materials for marker-assisted breeding in upland cotton.