Abstract:
t Fiber yield and quality are the most important
traits for Upland cotton (Gossypium hirsutum L.). Identifying high yield and good fber quality genes are the prime
concern of researchers in cotton breeding. Association
mapping ofers an alternative and powerful method for
detecting those complex agronomic traits. In this study, 198
simple sequence repeats (SSRs) were used to screen markers associated with fber yield and quality traits with 302
elite Upland cotton accessions that were evaluated in 12
locations representing the Yellow River and Yangtze River
cotton growing regions of China. Three subpopulations
were found after the estimation of population structure.
The pair-wise kinship values varied from 0 to 0.867. Only
1.59% of the total marker locus pairs showed signifcant
linkage disequilibrium (LD, p < 0.001). The genome-wide
LD decayed within the genetic distance of ~30 to 32 cM at
2
= 0.1, and decreased to ~1 to 2 cM at r
2
= 0.2, indicating the potential for association mapping. Analysis based
on a mixed linear model detected 57 signifcant (p < 0.01)
marker–trait associations, including seven associations for
fber length, ten for fber micronaire, nine for fber strength,
eight for fber elongation, fve for fber uniformity index,
fve for fber uniformity ratio, six for boll weight and seven
for lint percent, for a total of 35 SSR markers, of which 11
markers were associated with more than one trait. Among
marker–trait associations, 24 associations coincided with
the previously reported quantitative trait loci (QTLs), the
remainder were newly identifed QTLs/genes. The QTLs
identifed in this study will potentially facilitate improvement of fber yield and quality in the future cotton molecular breeding programs.
