Stability and transferability assessment of the cotton fiber strength QTL qFS-c7-1 on chromosome A07

Previously we identified a major cotton fiber strength QTL (qFS-c7-1) on chromosome A07 using a multi-parent advanced generation intercross (MAGIC) population. To assess the stability and transferability of this QTL and its utility in cotton breeding, we made ten new populations. These populations were developed from crosses between MAGIC recombinant inbred lines, or between cotton cultivars that are different from the MAGIC parents. A total of 2801 F₂ plants were grown and their fiber quality traits were measured. We also selected a subset of F₃ seeds from two populations, and grew F₃ progeny plots to further evaluate the stability of this QTL. Our results showed that the peak of qFS-c7-1 is at 70–72 Mb region. This QTL had a major effect on fiber strength explaining 21.9% phenotypic variance. Its effect on other fiber quality attributes such as micronaire, short fiber content, length and uniformity varied between populations, and no effect on fiber elongation was observed. The QTL effects were stable in the populations analyzed, and in different generations of the same population. The SSR and SNP markers near and within the QTL peak reported herein will assist selecting superior fiber quality traits in breeding, with a recommendation that the parental cotton lines should be analyzed using the seven DNA markers within the QTL peak before fully implementing marker assisted selection in a cotton breeding program.