Abstract
BackgroundGenetic 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.ResultsIn 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.ConclusionsThe present studies provide informative basis for improving cotton fiber quality in different populations.
Highlights
Genetic improvement in fiber quality is one of the main challenges for cotton breeders
Phenotypic variation ranged from 2.63% to 8.53% in both BC and recombinant inbred lines (RIL) populations for fiber length (FL), fiber strength (FS) and fiber micronaire (FM)
The results indicated wider range of phenotypic variation and larger heritability in recombinant inbred lines in paternal backcross (RIL-P) population than those in Paternal backcross population (BC/P) population for five fiber quality traits
Summary
Genetic improvement in fiber quality is one of the main challenges for cotton breeders. F14 recombinant inbred line (RIL) population was backcrossed to paternal parent for a paternal backcross (BC/P) population, deriving from one upland cotton hybrid. Numerous QTLs were detected based on mapping in recombinant inbred lines (RIL) populations of upland cotton (Wu et al 2009; Sun et al 2012; Ning et al 2014; Tan et al 2015; Shang et al 2015; Tang et al 2015; Zhang et al 2015b; Jamshed et al 2016; Li et al 2016; Ma et al 2017; Ijaz et al 2019). Wang et al (2016) detected 22, 14, 17, 3 and 20 QTLs for the five traits in two parental F8BC1 populations deriving from another hybrid of upland cotton. It offers opportunity to dissect QTLs for fiber quality traits using multiple populations of upland cotton
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