基于SSR标记的楠木核心种质构建

Construction of Core Collection of Phoebe zhennan Based on SSR Molecular Markers

楠木是我国特有的珍贵用材树种,研究楠木核心种质的构建策略对强化楠木资源保护与利用,加快楠木良种选育进程具有重要意义。利用14对SSR引物,以102份楠木种质资源为材料,利用M策略、随机取样法、遗传多样性最大法和等位基因最大法分别构建核心种质。采用等位基因数、有效等位基因数和Shannon’s信息指数等遗传多样性指标进行比较分析来确定最适合的楠木核心种质构建方法。14对SSR引物共检测到166个等位基因,平均有效等位基因数为4.875,Shannon’s信息指数为1.297,表明楠木种质资源具有较为丰富的遗传多样性。在较高抽样比例时,等位基因最大化、遗传多样性最大化法和M策略抽取的核心种质均对原有种质有较好的代表性。等位基因最大化法抽取的核心种质等位基因保留率与M策略均达100.00%,但其有效等位基因数和遗传多样性的保留率相对较低;遗传多样性最大化法抽取的核心种质的Shannon’s信息指数保留率与M策略相差不大,但其等位基因和有效等位基因数保留率低于M策略。综合考虑遗传多样性参数,M策略构建的核心种质能最大程度地代表原有种质,为最优的取样策略。主坐标分析结果也证明M策略构建的核心种质能够较为全面地代表楠木种质资源的遗传多样性。最后,利用M策略得到60份楠木核心种质,保留原有种质58.8%的种质材料,等位基因数、有效等位基因数和Shannon’s信息指数的保留率分别达到100.00%、120.51%和106.86%。依据14对SSR引物的扩增谱带,构建了60份核心种质的分子身份信息,能对每份核心种质进行准确识别和鉴定。本研究结果可为楠木种质资源的深入研究和加强利用、发掘优异基因资源提供理论依据和核心材料。

Phoebe zhennan is a precious and unique timber species in China.The establishment of a core collection have important value for the strengthen of resources protection and utilization,and speed up the breeding process of P.zhennan.Taking 102 germplasms of P.zhennan as materials.The methods of maximization strategy(M strategy),random sampling,simulated annealing algorithm maximizing the genetic diversity,and simulated annealing algorithm maximizing the number of alleles were used to construct the core collections using 14 SSR primers.The results showed that 166 alleles were detected by 14 SSR primers,and the average of the effective alleles was 4.875.The Shannon’s information index was 1.297,indicated relative high genetic diversity in the germplasms of P.zhennan.Comparative analysis showed that the core collections with relative high sampling proportion of constructed by maximization strategy,simulated annealing algorithm maximizing the genetic diversity,and simulated annealing algorithm maximizing the number of alleles were all showed high representativeness.The retention of alleles in core collections that constructed by simulated annealing algorithm maximizing the number of alleles and maximization strategy were all reached 100.00%,but the retention of the effective alleles and genetic diversity in core collection that constructed by algorithm maximizing the number of alleles were lower than maximization strategy.There was no obviously difference of the retention of Shannon’s information index in core collections that constructed by simulated annealing algorithm maximizing the genetic diversity and maximization strategy,but the alleles and effective alleles in core collection that constructed by maximization strategy were higher than simulated annealing algorithm maximizing the genetic diversity.Therefore,maximization strategy was the best sampling strategy in core collection construction according to the genetic diversity parameters.The principal coordinate analysis also showed that the core collection could represent the genetic diversity of the origin collection.The 60 germplasms includes 58.8% of the all germplasms,the retention of alleles,effective alleles,and Shannon’s information index were 100.00%,120.51%,and 106.86%.Specific molecular identity for 60 core collections were established by the bands of 14 SSR primers,which could accurately identification the core collections.Our results provided theoretical basis and core materials for further research,utilization,and excellent gene resource mining of P.zhennan germplasms.