| Cotton (Gossypium spp.) is one of the most important economic crops in the world. And China is the biggest country of cotton production, consumption and textile. As improving of life nationwide, consumption of cotton and textile products are rapidly increasing with higher quality requirement.Upland cotton (Gossypium hirsutum L.) and Sea Island cotton (G. barbadense) are two tetraploid cotton cultivars. Upland cotton (Gossypium hirsutum L.) yields high with moderate fiber quality. G. barbadense that’s good material for fine count yarn performs low yield with better fiber fineness and strength. Chromosome segment introgression lines (CSIL) consist of a series of near-isogenic lines covering whole genome, except for one homozygous chromosome segment transferred from donor parent in each line, the remaining parts of genome are the same as the recipient parent. It is ideal material for genome research and QTL mapping. Our lab has constructed the first set of CSILs with background of Upland cotton, which is introgressed by chromosome segment of Sea Island cotton. In the study, we selected four CSILs to cross with bacrossed parent TM-1, constructed four sub-separated populations for fine mapping fibre quality traits QTL. The main results are as following:1.In the study, we used four CSILs IL-07-3、IL-08-1、IL-19-10 and IL-02-3 as female parent to cross with bacrossed parent TM-1 respectively, constructed four sub-separated populations for fine mapping fibre quality traits QTL.2.The sieving results of molecular marker polymorphism could tell us that:there’re 9,9 and 14 pairs of polymorphic markers. Introgression segments of CSILs IL-07-3、IL-08-1、IL-19-10、IL-02-3 were located on cotton chromosome A7、A8、D5 and A2, whose lengths are 8.77、25.6、19.18and 20.16 cM respectively.3.In F2 generation of the population with the female parent IL-07-3,5 fibre quality QTL were detected,2 QTL are correlates with fiber length, their explanation ratios were 2.13%、 2.42%; we also detected 1 QTL for fiber strength,1 QTL for fiber uniformity and 1 QTL for fiber maturity, they separately explained 3.49%,3.51% and 2.65% of the phenotypic variance. In F2.3 generation,1 QTL for fiber length was detected and explained 2.65% of the phenotype variance.In F2:3 generation of the population with female parent IL-08-1,2 QTL were detected, 1 QTL for fiber length and 1 QTL for micronaire. And they explained 5.07% and 1.58% of the phenotypic variance.In F2.3 generation of the population with female parent IL-19-10,1 QTL was detected and it explained 3.02% of the phenotype variance.In F2 generation of the population with female parent IL-02-3,6 QTL were detected,2 QTL for micronaire,2 QTL for fiber elongation,1 QTL for fiber strength and 1 QTL for fiber mutarity. They separately explained 21.9%,19.8%,18.02%,16.84%,17.86% and 12.71% of the phenotype variance. In F2:3 generation,5 QTL were detected,2 QTLs for micronaire,1 QTL for fiber length,1 QTL for fiber elongation and 1 QTL for fiber maturity. They separately explained 9.48%,11.64%,8.59%,4.9% and 5.83% of the phenotype variance.4.In some regions, there are some fibre quality QTL clustered together, they mainly dispersed in the marker intervals of NAU2002-NAU2108 in the population with female parent IL-07-3 and NAU3626-NAU2994、NAU5804-NAU3485、NAU1072-NAU3626 and NAU5134-NAU3485 in the population with female parent IL-02-3. Meanwhile, with correlation analysis among phenotypes, we found that:phenotypes correspond to these clustered QTL almost correlates extremely significant.5. QTL detected in both F2 and F2:3 generations are as following:1 QTL for fiber length can be detected in the population with female parent IL-07-3.1 QTL for micronaire and 1 QTL for fiber elongation rate can be detected in the population with female parent IL-02-3. |
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