Efficacy of <i>qFL‐chr1</i>, a Quantitative Trait Locus for Fiber Length in Cotton (<i>Gossypium</i> spp.)

Abstract

In an earlier advanced‐backcross quantitative trait locus (QTL) analysis of an interspecific Gossypium hirsutum L. × Gossypium barbadense L. population, 28 fiber length QTLs were identified including qFL‐chr1 on chromosome 1 of the A‐subgenome. The G. barbadense allele at this QTL contributed to longer fibers and explained up to 24% of the phenotypic variance. To substantiate the association of this genomic region with fiber length, three BC 3 F 2 plants heterozygous for the genetic markers that delineate the qFL ‐ chr1 QTL were selected to construct three independent populations of near‐isogenic introgression lines (NIILs). The efficacy of qFL‐chr1 was evaluated among 140 NIILs grown in 2 yr. The results support the positive effect of qFL ‐ chr1 on fiber length. A single NIIL, R01‐40‐08, had about 94.3% of recurrent genome composition and significantly longer fiber than the recurrent parent when grown in Nanjing, China. Therefore, in addition to confirming the efficacy of qFL ‐ chr1 to enhance fiber length, this work provides a valuable genetic resource for the improvement of cotton.