QTL and genetic analysis controlling fiber quality traits using paternal backcross population in upland cotton

Abstract

Abstract Background Genetic improvement in fiber quality is one of the main challenges for cotton breeders. Quantitative trait loci (QTL) mapping provides a powerful approach to dissect the molecular mechanism in fiber quality traits. In present study, F14 recombinant inbred line (RIL) population was backcrossed to paternal parent for a paternal backcross (BC/P) population, deriving from one upland cotton hybrid. Three repetitive BC/P field trials and one maternal backcross (BC/M) field trial were performed including both two BC populations and the original RIL population. Results In total, 24 novel QTLs are detected for fiber quality traits and among which 13 QTLs validated previous results. Thirty-five QTLs in BC/P populations explain 5.01%–22.09% of phenotype variation (PV). Among the 35 QTLs, 23 QTLs are detected in BC/P population alone. Present study provides novel alleles of male parent for fiber quality traits with positive genetic effects. Particularly, qFS-Chr3–1 explains 22.09% of PV in BC/P population, which increaseds 0.48 cN·tex− 1 for fiber strength. A total of 7, 2, 8, 2 and 6 QTLs explain over 10.00% of PV for fiber length, fiber uniformity, fiber strength, fiber elongation and fiber micronaire, respectively. In RIL population, six common QTLs are detected in more than one environment: qFL-Chr1–2, qFS-Chr5–1, qFS-Chr9–1, qFS-Chr21–1, qFM-Chr9–1 and qFM-Chr9–2. Two common QTLs of qFE-Chr2–2 (TMB2386-SWU12343) and qFM-Chr9–1 (NAU2873-CGR6771) explain 22.42% and 21.91% of PV. The region between NAU4034 and TMB1296 harbor 30 genes (379 kb) in A05 and 42 genes (49 kb) in D05 for fiber length along the QTL qFL-Chr5–1 in BC/P population, respectively. In addition, a total of 142 and 46 epistatic QTLs and QTL × environments (E-QTLs and QQEs) are identified in recombinant inbred lines in paternal backcross (RIL-P) and paternal backcross (BC/P) populations, respectively. Conclusions The present studies provide informative basis for improving cotton fiber quality in different populations.

Keywords

• Fiber quality traits
• Common QTL
• Paternal backcross population
• Upland cotton