Mapping and Validation of Fiber Quality QTLs in Major Genetic Backgrounds of US Upland Cotton (Gossypium hirsutum L.)

Genetic backgrounds can have profound effects on the identification and performance of introgressed QTLs, therefore validation of the effects of these introgressed QTLs in multiple genetic backgrounds is essential before they are deployed in a marker assisted breeding program. In order to validate the effectiveness of fiber quality QTLs introgressed into Sealand 883 across genetic backgrounds, we developed four mapping populations by crossing Sealand 883 with Acala SJ-4, Deltapine 50, Paymaster HS 26, and GA 2004089 respectively, each representing a major genetic background of Upland cotton grown in the US. QTL mapping in F2 and F2:3 generations of each mapping population resulted in the identification of 31 fiber quality QTLs including 10 QTLs that were consistently detected over generations in all the four genetic backgrounds. Effects of genetic background on detection and performance of fiber quality QTLs was observed at multiple loci. Thirteen (42%) QTLs identified in this study were also reported in our previous studies where the favorable allele for six QTLs was contributed by Sealand 883. Our results validate Sealand 883 as a repository of fiber quality QTL that can be targeted via marker assisted selection to improve elite Upland germplasm.