基于ISSR标记初选格鲁桑类型桑树核心种质

Screening of Core Germplasms of Gelu Ecotype Mulberry Based on ISSR Marker

核心种质可以用最少份数的种质资源代表该物种及生态类型的遗传多样性。以收集自我国黄土高原的73份格鲁桑类型桑树种质资源为材料,利用15个ISSR引物共扩增出129条带,其中多样性条带为115条,多态性比率为89.15%。根据ISSR分子标记聚类结果和树型图,利用逐步聚类随机取样法和属性约简启发式算法对73份种质资源进行核心种质构建研究,2种方法分别初选出21份和16份格鲁桑类型桑树核心种质,核心种质样本的比率分别为28.77%、21.92%。利用统计软件SPSS 13.0,结合分子标记多态性位点数、多态性位点百分率、观测等位基因数、有效等位基因数、Nei's遗传多样性指数和Shannon's信息指数对2组核心种质的遗传多样性进行评价和t检验,结果显示:采用2种方法初选出的21份和16份格鲁桑核心种质都能很好地保存初始群体的遗传多样性和结构,但采用属性约简启发式算法所得16份核心种质的代表性要优于采用逐步聚类随机取样法所得的21份核心种质。最终确定以属性约简启发式算法初选的16份样本作为格鲁桑类型桑树核心种质。

Core germplasms are germplasm resources with the minimum number to represent a specific species and its ecotypes.Genetic diversity of 73 Gelu ecotype mulberry germplasm resources collected from loess plateau of China was analyzed using 15 ISSR primers.As a whole,129 bands were amplified,among which 115 were polymorphic,with a diversification rate of 89.15%.Based on clustering and cladogram of ISSR molecular markers,the stepwise clustering and random sampling method and the modified heuristic parsimony algorithm were employed to construct core germplasms for the 73 germplasm resources.The two methods yielded 21 and 16 core germplasms of Gelu ecotype mulberry,accounting for 28.77% and 21.97% of the samples tested respectively.By using statistical software SPSS 13.0 and combining with molecular markers＇ polymorphic loci,percentage of polymorphic loci,observed number of alleles,effective number of alleles,Nei＇s genetic diversity index and Shannon＇s information index to evaluate and conduct t tests to the genetic diversity of the two groups of core germplasm collections,the results showed that both the 21 and 16 core collections of Gelu ecotype mulberry obtained by the above two methods could conserve the genetic diversities and structures of the primary collections very well,and the 16 core collections from modified heuristic parsimony algorithm was superior to the 21 core collections from stepwise clustering and random sampling method.Finally,the 16 core collections from modified heuristic parsimony algorithm were defined as the core collections of Gelu ecotype mulberry.