Identification of quantitative trait loci for fiber quality, yield, and plant height traits in Upland cotton

Abstract

In cotton, most agronomic traits are controlled by polygenes. In this study, 110 F 6 recombinant inbred lines (RILs), derived from Upland cotton cross NC05AZ06 x NC11-2100, were used to develop a linkage map and to identify quantitative trait loci (QTL) for six fiber quality traits, three yield traits, and plant height. These RILs were genotyped using the CottonSNP63K array and phenotyped for fiber quality, yield traits, and plant height in 2-year field trials. Analysis of variance revealed significant (p < 0.05) differences among RILs for all traits studied, and the heritability estimates were moderate (30%-60%) to high (> 60%). Both positive and negative correlations were observed for fiber quality and yield traits. A total of 3,774 polymorphic SNP markers were used to develop a genetic map with an average marker density of 1.54 SNP/cM. Thirty QTL for fiber quality traits, yield traits, and plant height were detected on 15 different chromosomes, explaining 6.80%-20.02% of the phenotypic variance (PVE). Of these, 14 were major QTL (PVE > 10%), and three major QTL were detected in both years. Candidate gene analysis in the major QTL detected in both years and plant height QTL with PVE of 20.02% revealed five putative genes for fiber quality traits and one putative gene for plant height. The linkage map and identified QTL along with the candidate genes in the study could serve as additional breeding resources for Upland cotton genetic improvement.