利用棉花优质渐渗系进行纤维品质性状和衣分的QTL定位

QTL Mapping for Fiber Quality and Lint Percentage Traits of Cotton Using Elite Germplasm with Introgression of Gossypium barbadense L.

纤维品质和衣分是棉花育种改良的主要目标性状。为充分挖掘与纤维品质和衣分相关的优异基因资源,利用海岛棉优异纤维渐渗系Sealand(Se)和高产抗逆的陆地棉品种鲁棉研37号(L37)为亲本,构建了包含372个单株的F2群体,进行遗传图谱的构建和QTL定位的研究。从9628对引物中筛选到320对在亲本中具有多态的标记,多态率约为3.32%;连锁分析表明(LOD=6.5),有248个标记位点进入连锁群,分布在26条染色体上,覆盖区间为2347.63 cM,约占棉花基因组的52.76%,平均每条染色体9.54个标记,标记间平均间距为9.50 cM;利用F2群体的棉花纤维品质和衣分数据,共定位到20个与纤维品质性状和衣分相关的QTLs,其中纤维上半部平均长度和整齐度指数各2个,断裂比强度5个,马克隆值和伸长率各4个,衣分3个,贡献率为3.50%~16.82%;与纤维上半部平均长度、断裂比强度和伸长率相关的11个QTLs,增效基因均来自亲本Se,与马克隆值、整齐度指数和衣分相关的9个QTLs,增效基因均来自亲本L37。在D6染色体上鉴定到一个含有纤维上半部平均长度、断裂比强度和马克隆值的QTL簇,该区间包含有148个基因,通过GO富集分析和KEGG富集分析,并结合TM-1的转录组数据,获得了3个可能与纤维发育相关的基因:Gh_D06G0039、Gh_D06G0142和Gh_D06G0145。本研究为棉花纤维品质和衣分性状QTL的精细定位及相关候选基因的筛选奠定了基础。

Fiber quality and lint percentage are the main target trait of cotton breeding improvement.In order to explore the elite genetic resources of fiber quality,a genetic map is constructed and QTLs are detected based on an F2 population of 372 individuals derived from a cross between upland cotton Sealand(Se)(a superior fibre-quality germplasm of Gossypium hirsutum L.with G.barbadense L.introgressions)and upland cotton Lumianyan 37 Hao(L37)(a high-yield G.hirsutum L.cultivar).A total of 9628 primer pairs were used to screen polymorphism between the two parents,and 320 pairs of polymorphic primers were identified.The polymorphic primers accounted for 3.32%.Linkage test(LOD=6.5)indicated that 248 polymorphic loci could be mapped into 26 chromosomes and covered a total genetic distance of 2347.63 cM,which was approximately 52.76%of the cotton genome.The average number of marker loci per chromosome was 9.54,with a mean spanning distance of 9.50 cM.Twenty QTLs for fiber quality traits and lint percentage were identified,including two for fiber upper half length(FL),two for uniformity(FU),five for fiber strength(FS),four for micronaire(FM),four for elongation(FE)and three for lint percentage(LP).These QTLs could explain 3.50%-16.82%of the phenotypic variation.The favorable alleles of eleven QTLs for fiber upper half length,strength and fiber elongation were derived from Se,while the favorable alleles of nine QTLs for micronaire,fiber upper half length,uniformity and lint percentage were derived from L37.A QTL cluster including QTLs for fiber upper half length,strength and micronaire and containing 148 genes was identified on D6 chromosome.Three genes related to fiber development,Gh_D06G0039,Gh_D06G0142 and Gh_D06G0145,were identified by GO enrichment analysis and KEGG enrichment analysis combined with TM-1 transcriptome data.This study laid a foundation for fine mapping QTL of fiber quality and lint percentage of cotton and for identifying related candidate genes.