Association mapping is a useful tool for the detection of genes selected during plant domestication based on their linkage disequilibrium（LD）. This study was carried out to estimate genetic diversity, population str...Association mapping is a useful tool for the detection of genes selected during plant domestication based on their linkage disequilibrium（LD）. This study was carried out to estimate genetic diversity, population structure and the extent of LD to develop an association framework in order to identify genetic variations associated with drought and salt tolerance traits. 106 microsatellite marker primer pairs were used in 323 Gossypium hirsutum germplasms which were grown in the drought shed and salt pond for evaluation. Polymorphism（PIC=0.53） was found, and three groups were detected（K=3） with the second likelihood ΔK using STRUCTURE software. LD decay rates were estimated to be 13-15 cM at r2 0.20. Significant associations between polymorphic markers and drought and salt tolerance traits were observed using the general linear model（GLM） and mixed linear model（MLM）（P 0.01）. The results also demonstrated that association mapping within the population structure as well as stratification existing in cotton germplasm resources could complement and enhance quantitative trait loci（QTLs） information for marker-assisted selection.展开更多
The inference of genome ancestry and the estimation of molecular relatedness are of great importance for breeding efficiency and association studies. Seventy SSR loci, evenly distributed in 10 chromosomes, were assaye...The inference of genome ancestry and the estimation of molecular relatedness are of great importance for breeding efficiency and association studies. Seventy SSR loci, evenly distributed in 10 chromosomes, were assayed for polymorphism among 187 commonly used maize （Zea mays L.） inbreds which represent the genetic diversity in China. The identified 290 alleles served as raw data for estimating population structure using the coalescent linked loci, based on the ADMIXTURE model. Population number, K, has been inferred to be between five and seven. Specifying five subpopulations （K = 5） led to a distinct decrease and specifying K to be greater than six resulted in only minimal increases in the likelihood value. Therefore, population number, K, has been inferred into six subpopulations, which are PA, BSSS （includes Reid）, PB, Lan （Lancaster Sure Crop）, LRC （Luda Reb Cob, a Chinese landrace, and its derivatives）, and SPT （Si-ping-tou, a Chinese landrace and its derivatives）. The Kullback-Leibler distance of pairwise subpopulation was also inferred as n × p （187 ×6） Q matrices, which gave a detailed percentage of genetic composition of six subpopulations and molecular relatedness of each line. The genome-wide linkage disequilibrium （LD） indicated that the asso- ciation studies in QTLs and/or candidate genes might avoid nonfunctional and spurious associations, as most of the LD blocks were broken among diverse germplasm. The defined population structure has given us a clear genetic structure of these lines for breeding practice and established a good basis for association analysis.展开更多
【目的】分析山西谷子地方品种遗传多样性和群体遗传结构,筛选与谷子农艺性状相关联的分子标记,为谷子杂交组合亲本选配及分子标记辅助育种提供依据。【方法】利用96对SSR标记对595份山西谷子核心资源进行全基因组扫描,采用PowerMarker ...【目的】分析山西谷子地方品种遗传多样性和群体遗传结构,筛选与谷子农艺性状相关联的分子标记,为谷子杂交组合亲本选配及分子标记辅助育种提供依据。【方法】利用96对SSR标记对595份山西谷子核心资源进行全基因组扫描,采用PowerMarker 3.25软件分析群体遗传多样性,利用STRUCTURE 2.3.4软件分析群体遗传结构,使用TASSEL 2.1软件中GLM(general linear model,Q)和MLM(mixed linear model,Q+K)2种方法,进行表型和标记关联分析。【结果】96对SSR引物共扩增出828个等位变异,平均每对引物扩增到8.6个,变化范围为2—26;基因多样性指数变化范围为0.005—0.941,平均为0.610;多态信息量变化范围为0.005—0.938,平均为0.577;各位点杂合度变化范围为0—0.050,平均位点杂合度仅为0.016。群体结构分析将595份核心资源分为3个亚群。4560个SSR位点成对组合中,共线性组合和非共线性组合之间都存在一定的连锁不平衡。D′统计概率(P<0.01)支持的LD成对位点1955个,占全部位点组合的42.9%,D′平均值为0.23。通过GLM方法共检测到12个极显著性位点(P<0.01),表型变异解释率为2.34%—13.94%,平均为6.33%,贡献率较高的等位变异位点是CAAS2050(R2=13.94%)和B153(R2=11.36%);通过MLM方法共检测到9个极显著性位点(P<0.01),表型变异解释率为2.80%—9.22%,平均为5.16%,贡献率较高的等位变异位点是P89(R2=9.22%)和P3*(R2=8.28%);2种方法共同检测到的极显著性位点有7个。【结论】利用SSR标记分析了595份山西谷子核心资源的遗传多样性和群体遗传结构。2种关联分析模型中,GLM方法关联到12个标记与节数、株高、颈长、茎粗、穗长、穗粗、码数、码粒数、蛋白质含量9个性状相关;MLM方法关联到9个标记与节数、颈长、叶宽、茎粗、穗粗、码数、码粒数、千粒重8个性状相关。展开更多
基金supported by the National Natural Science Foundation of China(31201246)the Project of International Science and Technology Cooperation and Exchange from the Ministry of Science and Technology,China(2010DFR30620-3)
文摘Association mapping is a useful tool for the detection of genes selected during plant domestication based on their linkage disequilibrium（LD）. This study was carried out to estimate genetic diversity, population structure and the extent of LD to develop an association framework in order to identify genetic variations associated with drought and salt tolerance traits. 106 microsatellite marker primer pairs were used in 323 Gossypium hirsutum germplasms which were grown in the drought shed and salt pond for evaluation. Polymorphism（PIC=0.53） was found, and three groups were detected（K=3） with the second likelihood ΔK using STRUCTURE software. LD decay rates were estimated to be 13-15 cM at r2 0.20. Significant associations between polymorphic markers and drought and salt tolerance traits were observed using the general linear model（GLM） and mixed linear model（MLM）（P 0.01）. The results also demonstrated that association mapping within the population structure as well as stratification existing in cotton germplasm resources could complement and enhance quantitative trait loci（QTLs） information for marker-assisted selection.
文摘The inference of genome ancestry and the estimation of molecular relatedness are of great importance for breeding efficiency and association studies. Seventy SSR loci, evenly distributed in 10 chromosomes, were assayed for polymorphism among 187 commonly used maize （Zea mays L.） inbreds which represent the genetic diversity in China. The identified 290 alleles served as raw data for estimating population structure using the coalescent linked loci, based on the ADMIXTURE model. Population number, K, has been inferred to be between five and seven. Specifying five subpopulations （K = 5） led to a distinct decrease and specifying K to be greater than six resulted in only minimal increases in the likelihood value. Therefore, population number, K, has been inferred into six subpopulations, which are PA, BSSS （includes Reid）, PB, Lan （Lancaster Sure Crop）, LRC （Luda Reb Cob, a Chinese landrace, and its derivatives）, and SPT （Si-ping-tou, a Chinese landrace and its derivatives）. The Kullback-Leibler distance of pairwise subpopulation was also inferred as n × p （187 ×6） Q matrices, which gave a detailed percentage of genetic composition of six subpopulations and molecular relatedness of each line. The genome-wide linkage disequilibrium （LD） indicated that the asso- ciation studies in QTLs and/or candidate genes might avoid nonfunctional and spurious associations, as most of the LD blocks were broken among diverse germplasm. The defined population structure has given us a clear genetic structure of these lines for breeding practice and established a good basis for association analysis.
文摘【目的】分析山西谷子地方品种遗传多样性和群体遗传结构,筛选与谷子农艺性状相关联的分子标记,为谷子杂交组合亲本选配及分子标记辅助育种提供依据。【方法】利用96对SSR标记对595份山西谷子核心资源进行全基因组扫描,采用PowerMarker 3.25软件分析群体遗传多样性,利用STRUCTURE 2.3.4软件分析群体遗传结构,使用TASSEL 2.1软件中GLM(general linear model,Q)和MLM(mixed linear model,Q+K)2种方法,进行表型和标记关联分析。【结果】96对SSR引物共扩增出828个等位变异,平均每对引物扩增到8.6个,变化范围为2—26;基因多样性指数变化范围为0.005—0.941,平均为0.610;多态信息量变化范围为0.005—0.938,平均为0.577;各位点杂合度变化范围为0—0.050,平均位点杂合度仅为0.016。群体结构分析将595份核心资源分为3个亚群。4560个SSR位点成对组合中,共线性组合和非共线性组合之间都存在一定的连锁不平衡。D′统计概率(P<0.01)支持的LD成对位点1955个,占全部位点组合的42.9%,D′平均值为0.23。通过GLM方法共检测到12个极显著性位点(P<0.01),表型变异解释率为2.34%—13.94%,平均为6.33%,贡献率较高的等位变异位点是CAAS2050(R2=13.94%)和B153(R2=11.36%);通过MLM方法共检测到9个极显著性位点(P<0.01),表型变异解释率为2.80%—9.22%,平均为5.16%,贡献率较高的等位变异位点是P89(R2=9.22%)和P3*(R2=8.28%);2种方法共同检测到的极显著性位点有7个。【结论】利用SSR标记分析了595份山西谷子核心资源的遗传多样性和群体遗传结构。2种关联分析模型中,GLM方法关联到12个标记与节数、株高、颈长、茎粗、穗长、穗粗、码数、码粒数、蛋白质含量9个性状相关;MLM方法关联到9个标记与节数、颈长、叶宽、茎粗、穗粗、码数、码粒数、千粒重8个性状相关。
