Molecular tagging of QTLs for fiber quality and yield in the upland cotton cultivar Acala-Prema

Cotton is a high-value per acre crop that is produced as a raw material for the textile industry. With the development of new technologies in the textile industry, much attention has been paid to fiber quality in conjunction with yield. The introgression cultivar Acala Prema is extensively planted in the Carolina/USA for its good fiber qualities, high yields and tolerance to Verticillium wilt. To conduct QTL mapping for fiber quality and yield in Acala-Prema, we developed a population of 180 recombinant inbred lines (RILs) from a single seed derived from a cross between this line and Chinese cultivar 86-1. We examined the yield performance of the RILs in five Chinese environments and fiber qualities in seven Chinese environments. A genetic linkage map comprising 279 loci was constructed using this RIL population, chiefly with SSR markers, and QTLs were repeatedly identified across diverse environments using the composite interval mapping method. A total of 86 nonredundant QTLs for yield and its components and fiber qualities were independently detected in five or seven environments; Prema alleles were responsible for the increase in trait values for 46 QTLs, while 86-1 was responsible for 40 QTLs. Notably, we detected the stable fiber strength QTL qFS-D3-1, which explained 4.51-17.55 % of PV, with LOD scores ranging from 2.83 to 7.09, and the fiber length qFL-D11-1, which explained 10.02-25.34 % of the PV. Eighteen environment epistatic QTLs were also detected. The QTLs detected in this study provide new information for improving fiber quality and may be especially valuable for marker-assisted selection.