紫斑牡丹表型性状与SSR分子标记的关联分析

Association analysis of phenotypic traits with SSR markers in Paeonia rockii

利用筛选出的11对多态性简单重复序列（SSR）标记对99份紫斑牡丹材料进行多态性扫描,在分析其遗传多样性和群体结构的基础上,采用TASSEL2.1软件的一般线性模型（GLM）进行标记与32个观赏性状的关联分析。结果表明：11个多态性SSR标记共检测到94个等位变异,平均每个位点检测到等位变异8.5个;引物的多态性信息含量（PIC）变幅为0.146~0.850,平均值为0.593;遗传多样性变幅为0.152~0.862,平均为0.630。群体结构分析将供试材料划分为3个亚群;通过关联分析,发现5个标记位点与6个性状显著关联（P〈0.01）,各标记位点对表型变异的解释率为30.4%~55.8%,其中FJ024285和FJ024294标记与株高相关联,FE528073与顶小叶长、柱头颜色和房衣颜色相关联,FJ024287与柄叶比相关联,EU678295与色斑大小相关联。研究表明：所选紫斑牡丹种质资源群体的群体结构简单、遗传变异较为丰富,适用于紫斑牡丹目标性状的关联分析。关联分析能够有效地找到与紫斑牡丹表型性状紧密连锁的SSR标记,用于分子标记辅助育种。

In order to provide a genetic basis for studies on complex quantitative traits and for molecular marker assisted breeding of tree peony,the genetic diversity of Paeonia rockii was determined by using SSR markers and their association with important ornamental traits was detected. A total of 11 simple sequence repeat（ SSR） markers were screened for polymorphism among 99 accessions,and then the genetic diversity of these materials was detected. Through analyzing population structure,association analysis between SSR markers and 32 horticultural traits were performed using TASSEL2. 1 GLM（ general linear model） programs. The results showed that a total of 94 alleles were identified with 8. 5 alleles per locus.The polymorphism information content（ PIC） value ranged from 0. 146 to 0. 850,with an average of0. 593. The genetic diversity ranged from 0. 152 to 0. 862,with the mean of 0. 630. Population structure analysis showed that 99 Paeonia rockii materials were composed of 3 subpopulations. Association analysis found that there were 5 SSR markers associated with 6 horticultural traits,and the rate of explanation on the phenotype of related marker ranged from 30. 4% to 55. 8%. Among them,FJ024285 and FJ024294 were associated with plant height; FE528073 was associated with top-leaf length,stigma color and disk color; FJ024287 was associated with length ratio of petiole and compound leaf; EU678295 was associated with blotch size. An abundant genetic variation but week population structure was detected in Paeonia rockii accessions,indicating that the association population is representative and suitable for further association analysis of quantitative traits in tree peony. Association analysis is a promising approach tofind markers tightly linked with phenotypic traits,and the markers obtained in the present study provide foundation for molecular marker assisted breeding.