QTL analysis for gossypol and protein contents in upland cottonseeds with two different genetic systems across environments

Genetically improved cottonseed with high protein content and low or no gossypol content could be suitably processed for human and animal consumption. In the present study, quantitative trait loci (QTL) associated with the genetic effects including QTL main effects and QTL x environment interaction effects from tetroploid maternal plant genome and tetroploid embryo genome were simultaneously identified for protein and gossypol contents of cottonseeds. This is to help understand the QTL and QTL x environment interactions from embryo and maternal genomes for these two traits, and provide more effective information for their improvement in cottonseed through maker-assisted selection. The experiment was carried out on an immortal F-2 population comprising 376 lines obtained among 188 recombinant inbred lines (RILs) derived from a cross between parents HS46 and MARKCBUCAG8US-1-88, grown in 2009 and 2010. Twelve QTL for protein content (PC) and ten for gossypol content (GC) were detected using a genetic linkage map comprising 388 molecular markers. Among them, five QTL for gossypol content and six QTL for protein content were found in two different environments, explaining 62.95 and 58.52 % of phenotypic variances, respectively. A total of nine QTL were associated with these two traits, which were subsequently mapped to chromosome 3, 5, 6, 15, 18, 22 and 25. Six of these QTL were also found to have environmental interaction effects. The results from this study could be very useful in adopting effect strategies for protein improvement and gossypol elimination in cottonseeds.