死亡植株对新疆野苹果种群遗传多样性的影响

Effect of Death Individual on the Genetic Diversity of Malus sieversii Population

新疆野苹果（Malus sieversii）为国家二级保护植物和重要的野生果树种质资源。选取遭受小吉丁虫等病虫害破坏最为严重的新源县种群为对象,利用微卫星（SSR）标记死亡植株和存活植株的基因型,对比两者间的遗传差异,探究树木死亡对新疆野苹果种群遗传多样性的影响。结果表明：（1）死亡植株与存活植株间没有显著的遗传分化,这说明新疆野苹果植株死亡不存在遗传相关性,为随机死亡过程;（2）树木死亡对新源县种群的遗传结构未产生重大影响,遗传多样性水平仅轻微减小,但丢失了许多低频度等位基因;（3）未来的监测和评价中,等位基因数（Na）比遗传多样性指数能更有效地反映新疆野苹果遗传资源变化。

Malus sieversii is one of the national second-class protective plants and an important wild fruit germplasm resources. In this study,the M. sieversii population in Xinyuan County,Xinjiang was selected to research the genetic difference between the death and alive individuals of M. sieversii suffering from the serious diseases and insect pests than other populations,the effect of death individuals on the genetic diversity of M. sieversii was evaluated,and the genotypes of death and alive individuals were marked using the microsatellite markers. The results are as follows：（1） There was no significant genetic divergence between the death and alive individuals,which indicated that the death of M. sieversii was random and out of genetic correlation;（2） Genetic structure of M. sieversii population in Xinyuan was not significantly influenced by tree death. The level of genetic diversity decreased slightly after the tree death,but a lot of low frequency alleles were lost;（3） During the future monitoring and evaluation of the change of M. sieversii genetic resources,the number of alleles（ Na） was more suitable for effectively reflecting the variation of genetic resources than the indexes of genetic diversity.