Identification Of QTL For Yield And Fiber Quality Traits In Hybrid Cotton CCRI 70

CCRI70 as a upland cotton cultivar is widely planted for it's high yield and excellent fiber quality. To explore it's molecular mechanism, the two parents of SGK156 and 901-001 were crossed to establish a F₂ population. Simple sequence repeats ?SSR? technique was performed to construct of genetic map. Based on the F₂ population, the F_2.3, F_2:4 and F_2:5 were obtained for QTL mapping of fiber quality and yield component traits by composite interval mapping ?CIM?. The stable and common QTL are expected, which could be further used for the molecular genetic mechanism of fiber quality and yield component traits and MAS breeding.1. Four generation segregation populations developed from the cross between SGK156 and 901-001 were used for phenotypic traits analysis, which revealed the normal distribution and transgressive segregation for the most of yield and fiber quality traits in the different generations. This result is accorded with the fundamental regularity of quantitative traits.2. Correlation analyses between different traits were performed based on covariance. MIC was significantly and negatively correlated with FL, FS, and non-significant correlated with FU and FE. LP was mainly significantly and negatively correlated with fiber length and strength. BW and SI was significantly and positively associated with fiber length and strength. PH, FB and BN showed mainly non-significant correlation with the fiber traits.3.14280 SSRs were used for genotypic analysis,267 of them showed polymorphism between SGK156 and 901-001.250 F2 plants were used for the construction of genetic map for the QTL of fiber yield and quality traits.342 polymorphic loci were found and used for a final genetic map, which contains 312 loci with 35 linkage groups, and a total length of 1929.9 cM, an average of 6.19cM and spanning 43.34% genome of Upland cotton. The longest linkage group includes 33 loci, while the shortest group contains 2 loci.4. Based on composite interval mapping ?CM?, a total of 153 QTLs were identified in F₂?F_2:3?F_2:4 and F_2:5, explaining 1.01-27.80% of phenotypic variation ?PV?, including 79 of the yield components and 74 of the fiber quality traits.39 QTLs could be detected in at least two generation with 5 for FL, FE and MIC, respectively; 3 for FS and SI, respectively; 4 for FU and BW, respectively; 9 for LP, and 1 for FB. Compared with the previous reports,20 common QTLs were identified with 3 for FL, MIC and LP, respectively; 2 for FS, FU, FE and BW, respectively; 1 for SI, PH and BN. These stable and common QTL in diffident populations lays a solid foundation for MAS breeding.