陆地棉纤维品质性状关联分析及优异等位基因挖掘

本研究检测了214个陆地棉材料在多环境下的纤维品质指标(上半部平均长度、断裂比强度、马克隆值、伸长率和整齐度),选用在棉花基因组上均匀分布多态性较好的259个SSR标记对供试群体进行基因型检测,利用Tassel软件中的GLM(Q)方法挖掘与纤维品质指标相关的QTLs,依据表型效应值鉴别优异等位变异位点及典型材料。结果显示:同一纤维品质性状在3个地点2~3年内变化趋势相对稳定,纤维上半部平均长度、断裂比强度和整齐度三者之间呈正相关(P<0.01),纤维上半部平均长度/断裂比强度均和马克隆值/伸长率负相关。259个SSR标记共检测到309个等位基因,涉及774个基因型,多态性信息含量(PIC,polymorphic information content)平均为0.2688,基因多样性指数平均为0.2239。按照基因型数据可将该群体划分为2个亚群。通过关联分析获得与纤维品质相关的等位变异位点134个(P<0.01),在3个及以上环境中均可检测到的位点有30个,有3个位点(NAU6177、DPL0886、NAU3607)在7个环境中分别与断裂比强度、马克隆值、伸长率显著关联(P<0.01),最高表型变异解释率分别为11.14%、5.74%和13.99%。31个位点同时与2个及以上纤维品质指标相关,其中,NAU 6177与5个纤维品质指标均显著关联(P<0.01)。与已发表结果比对,17个QTL已被报道与纤维品质性状相关,10个QTL与前人关联指标相同。分析多环境纤维品质关联位点的表型效应,获得72个等位变异位点,5份携带优异等位基因载体材料。本研究在多环境下挖掘与陆地棉纤维品质指标关联的分子标记,同时鉴别携带优异等位变异基因的典型载体材料,为棉花纤维品质分子标记辅助选择及目标基因定位提供有益信息。

Exploration of Elite Alleles Related with Fibre Quality Traits in Gossypium hirsutum L.by Association Analysis

In this study,five fiber quality indexes(Fiber upper half mean length FUHML,Fiber strength FS,Micronaire value MV,Fiber elongation FE,Fiber uniformity FU)of 214 upland cotton materials were tested under seven environments,and Boxplot were drew by SPSS19.0,and the heritability,correlation and phenotypic effect values of the traits were calculated by using the phenotypic data analyzed by BLUP.259 SSRs with high polymorphism and uniform distribution on 26 chromosomes were used to scan polymorphism in 214 cotton materials,the polymorphism information of primers were calculated by Power Marker 3.25,and molecular marker data and phenotypic traits were analyzed by the method of GLM(General Linear Model)(Q)in TASSEL software,phenotypic effect values were used to identify excellent allelic variants and typical materials carrying elite alleles.The result showed that the same one fiber quality trait had a relatively stable change trend in two to three years in three regions.There were positive correlations among FUHML,FS and FU(P<0.01),and FUHML/FS and MV/FE were negatively correlated.A total of 309 alleles and 774 genotypes were detected.The average polymorphic information content(PIC)per marker was 0.2688,and the average genetic diversity index was 0.2239.Two hundred and fourteen upland cotton materials were divided into two subgroups by analysis of population genetic structure.A total of 134 loci associated with fiber quality traits were detected(P<0.01),among them,thirty loci could be detected stably in three or more environments.Three loci(NAU6177,DPL0886,NAU3607)were found to be significantly associated with FUHML/FS,MV and FE respectively in seven environments(P<0.01),the maximum explanation rate up to 11.14%,5.74%and 13.99%respectively.Thirty-one loci related to more than two fiber traits simultaneously,including the loci near NAU6177 related to aforementioned five fiber quality indexes(P<0.01).Compared with reported results,seventeen QTLs in this study has been reported to be related to fiber quality,in which 10 QTLs associated with the same traits.Based on the results,seventy-two alleles related with fiber quality were identified by phenotypic effect analysis respectively.Specifically,the allelic variation loci with the maximum increasing effect of FUHML,FS,MV and FE were NAU5387b(+0.95 mm),NAU5387b(+1.25 cN/tex),NAU943a(+0.40),and COT002a(+0.62)respectively,and the allelic variation loci with the maximum decreasing effect of FUHML,FS,MV and FE were NAU6177e(-1.21 mm),NAU6177d(-1.43 cN/tex),CIR286b(-0.78),and NAU5387b(-0.40)separately.Furthermore,five typical materials carrying elite alleles were selected,which were Ji 228(FUHML),Xinluzao 25(FUHML,FS),Ji N71(FS),Xinluzhong 36(MV)and Xuzhou 142(FE).In conclusion,stable molecular markers associated with fiber quality were revealed by association analysis,and elite alleles and typical materials carrying elite alleles were identified,which could provide a reference for molecular assisted selection of upland cotton about fiber quality.