QTL mapping of fiber quality traits with a composite cross population in upland cotton (Gossypium hirsutum L.) | 利用复合杂交群体定位陆地棉纤维品质性状QTL

Chinese. 为发掘陆地棉纤维品质性状基因/数量性状基因座(quantitative trait loci, QTL)，本研究以陆地棉(Gossypium hirsutum L.)优质品种渝棉1号分别与贝尔斯诺和中棉所35杂交获得F1代，随后利用两个F1再次杂交得到复合杂交群体。利用6 565对SSR引物筛选渝棉1号、中棉所35和贝尔斯诺，获得155对多态性引物。对检测[(渝棉1号×中棉所35)×(渝棉1号×贝尔斯诺)] F1复合杂交群体标记基因型获得的158个位点进行遗传连锁分析，构建的遗传图谱包含102个位点，覆盖1 199.0 cM。利用多QTL(multiple-QTL model,MQM)作图法，检测到11个纤维品质性状QTL，包括4个纤维长度、2个长度整齐度和5个纤维比强度QTL。11个QTL分布于4条D基因组染色体。本研究表明，陆地棉不同品种同一纤维品质性状QTL等位基因存在差异；三亲本杂交群体不仅可以提高群体多态性分子标记比例，而且可以显示同一QTL在不同遗传背景的等位基因表现差异。

English. To identify QTL related with fiber qualities in upland cotton (Gossypium hirsutum L.), a composite cross population was derived from the cross between (Yumian 1 × CRI 35) F1 and (Yumian 1 × Belshinuo) F1. A total of 155 SSR polymorphic primer pairs were obtained by selecting 6 565 primer pairs among upland cotton cultivars, CRI 35, Yumian 1 and Belshinuo. Genetic linkage analysis was conducted on 158 loci, which were obtained from genotyping a composite cross population, [(Yumian 1 × CRI 35) × (Yumian 1 × Belshinuo)] F1, and a genetic linkage map was constructed. The map contained 102 SSR loci and covered a whole length of 1 199.0 cM. Based on multiple QTL mapping method, eleven QTLs for fiber quality traits were identified, including four for fiber length, two for uniformity, and five for fiber strength. Eleven QTLs were mapped on four D-genome chromosomes. The present study shows that different upland cotton cultivars have different alleles of identical QTL for the same fiber quality trait. Composite cross population with three parents can increase the polymorphic ratio of DNA marker, and detect the different alleles of identical QTL in different backgrounds.