生境片段化对新疆野苹果种群遗传结构的影响

Effect of habitat fragmentation on the population genetic structure of Malus sieversii

生境片段化对植物种群具有复杂的遗传效应。在地理种群内部,新疆野苹果(Malus sieversii)呈现出多个片段化小群体。本研究选取遗传多样性较高的巩留种群作为研究对象,利用微卫星(SSR)标记采自5个小群体样点的101个植株样品基因型。通过分析不同小群体间的遗传多样性差异与遗传谱系关系,来探究生境片段化对新疆野苹果种群遗传结构的影响。结果表明:5个小群体间存在着遗传多样性差异,其中处于边缘位置的萨哈和小莫合尔2小群体保存了高水平的遗传多样性;由于地理隔离效应作用,这5个小群体可以划分为东西两个不同的遗传谱系。建议在将来开展的新疆野苹果种质资源保育和核心种质库构建过程中,应当注重这些边缘小群体和不同的遗传谱系。

Habitat fragmentation has complex genetic effects on plant populations. Malus sieversii exists in a few small fragmented subpopulations within a geographical population. For this study,we chose the geographical population of Gongliu,which has a high level of genetic diversity. The genotypes of 101 individuals from five subpopulations were marked using SSR loci. By analyzing the difference in genetic diversity and the genetic relationships among these five subpopulations,we aimed to investigate the effect of habitat fragmentation on the population genetic structure of Malus sieversii. The results showed that different levels of genetic diversity existed among these five subpopulations,in which a high level of genetic diversity was shown in marginal subpopulations of Saha and Xiaomoheer 2. These five subpopulations were clustered into two genetic lineages,which displayed an east-west split due to the effect of geographical isolation. It is proposed that these marginal subpopulations and different genetic lineages should be considered during the processing of germplasm resource protection and the core collection of germplasm for M. sieversii.