Identification of cotton fiber quality quantitative trait loci using intraspecific crosses derived from two near-isogenic lines differing in fiber bundle strength

Cotton fiber properties are very important to the yarn quality. Modern high-speed textile operations around the world require long, strong and fine cotton fibers. The objective of this research was to identify stable fiber quantitative trait loci (QTLs) that could be used in cotton breeding through marker-assisted selection (MAS). Two cotton lines, MD90ne and MD52ne, are near-isogenic with significant differences in fiber properties, especially strength. Fiber samples from 734 progeny plants of two F2 populations (A and B) derived from crosses between MD90ne and MD52ne were collected at Stoneville, MS, USA in 2012. Fiber quality attributes were measured using a High Volume Instrument 1000. A simple sequence repeat (SSR) genetic linkage map with 165 loci covering 632.53 cM was constructed using population A, consisting of 356 F2 individuals and used for identifying QTLs related to fiber bundle strength (FBS), short fiber index (SFI) and upper-half mean fiber length (UHML). One QTL for FBS originating from the stronger fiber parent MD52ne was identified on chromosome (Chr.) 3. Three QTLs each for SFI and UHML were identified on Chrs. 3, 4 and 14 and Chrs. 3, 11 and 24, respectively. Population B, consisting of 378 F2 progeny, was used to confirm these QTLs by analyzing 57 SSR markers mapped on Chrs. 3, 14 and 24. Three QTLs-qFBS-c3, qSFI-c14 and qUHML-c24-were confirmed and appeared stable. These three QTLs could potentially be used in breeding to improve cotton fiber quality through a MAS strategy.