棉花陆海渐渗系次级分离群体产量和纤维品质QTL定位

QTL mapping for yield and fiber quality traits in secondary segregate population of cotton chromosome segment introgression lines

【目的】利用海岛棉渐渗系挖掘与产量和纤维品质性状相关的优异基因/数量性状位点(quantitative trait loci,QTL),为培育高产且纤维品质优异的棉花品种提供有用的信息。【方法】利用优异陆海渐渗系材料MBI9626与高产、适应性广的陆地棉品种中棉所36构建了包含152个单株的BC_(6)F_(2)次级分离群体,以筛选的109个简单重复序列(simple sequence repeat,SSR)标记检测亲本和群体的基因型,结合多年多代的表型数据,定位产量和纤维品质性状的QTL。【结果】基因型分析表明,MBI9626中中棉所36背景的比例为94.8%。在BC_(6)F_(2)、BC_(6)F_(23)和BC_(6)F_(24)群体中共检测到28个与产量、纤维品质性状相关的QTL,分布在6条染色体上。其中:产量相关的QTL有16个,解释2.25%~6.14%的表型变异,包括6个多年多环境稳定的QTL;纤维品质相关的QTL有12个,解释2.49%~12.30%的表型变异,包括2个多年多环境稳定的QTL。新检测到19个QTL,包括多环境稳定的5个。在D3染色体上鉴定到1个包含6个QTL的QTL簇,该区间包含233个基因,通过基因本体(gene ontology,GO)聚类和KEGG(Kyoto encyclopedia of genes and genomes)通路富集分析,并结合TM-1的转录组数据,筛选出6个可能与纤维发育相关的基因:GH_D03G1428、GH_D03G1466、GH_D03G1518、GH_D03G1570、GH_D03G1586和GH_D03G1640。【结论】本研究检测到28个与棉花产量、纤维品质相关的QTL,为进一步精细定位、候选基因克隆和分子标记辅助选择奠定基础。

[Objective]The aim of this study is to explore the elite gene/quantitative trait loci(QTL)resources of yield and fiber quality,and to provide useful information for developing cotton varieties with high yield and excellent fiber quality.[Methods]A superior chromosome segment substitution line MBI9626,and a high-yield and wide-adaptability upland cotton CCRI 36 were selected to construct a secondary segregation population BC_(6)F_(2) which contained 152 individuals.And 109 selected simple sequence repeat(SSR)markers were used to genotyping parents and the population,and QTL mapping for yield and fiber quality traits was conducted based on genotype data and phenotype data.[Results]Genotyping resutts showed MBI9626 recovered to 94.8%of the genetic background of CCRI 36.A total of 28 QTLs related to yield and fiber quality traits were detected in BC_(6)F_(2),BC_(6)F_(23),and BC_(6)F_(24) populations,which were distributed on 6 chromosomes.Among them,there are 16 QTLs related to yield,accounting for 2.25%-6.14%of the phenotypic variation,including 6 stable QTLs;12 QTLs related to quality traits,accounting for 2.49%-12.30%of the phenotypic variation,including 2 stable QTLs.There were 19 newly discovered QTLs,including 5 stable QTLs.And 233 genes were identified in a QTL cluster with 6 QTLs on D3 chromosome.Based on gene ontology(GO)cluster and Kyoto encyclopedia of genes and genomes(KEGG)analysis and TM-1 transcriptome data,6 candidate genes were screened to be involved in fiber development,namely GH_D03G1428、GH_D03G1466,GH_D03G1518,GH_D03G1570,GH_D03G1586,and GH_D03G1640.[Conclusion]Twenty-eight stable QTLs related to cotton yield and fiber quality were identified and would lay a solid foundation for fine mapping and cloning of candidates genes and marker assisted selection.