杜梨实生繁殖群体遗传多样性的SSR分析

SSR Analysis of Genetic Diversity in Germplasm Resources of Pyrus betulaefolia Bge.and Its Seedling Populations

为了解不同数量杜梨实生群体组的遗传多样性,从59株人工培育的实生杜梨群体中随机抽取5、8、10、15、20、30和40株组成不同的群体组,利用29对SSR引物对杜梨不同群体遗传特性进行分析。结果表明:(1)7个不同的群体组的多态位点数120～253个、多态位点百分率47.00%～89.83%、Nei’s遗传多样性指数0.128 8～0.145 4、香农指数0.205 8～0.255 4、平均等位基因数1.470 0～1.988 3和有效等位基因数1.196 1～1.203 4。(2)各群体组与对照群体组的遗传多样性指数的比较结果表明,大于15株的群体组与对照群体组相比,群体大小对群体组内遗传多样性水平没有显著性影响。(3)通过对各群体组内的稀有等位基因数目及其变化(增加/减少)分析表明,群体大小可显著影响杜梨种质实生群体内稀有等位基因的数目变化,主要是减少稀有等位基因的数目。研究认为,杜梨种质保存、更新的适宜群体量为15株以上。

In order to know the genetic diversity of wild pear（Pyrus betulaefolia Bge.） with different population sizes,seven groups with 5,8,10,15,20,30 and 40 seedlings,respectively,were selected randomly from a wild pear population of 59 individuals.（1）Polymorphic sites were 120~253,percentage of polymorphic site 47.00%~89.83%,Nei＇s genetic diversity index 0.128 8~0.145 4,Shannon＇s information index 0.205 8~0.255 4,number of average alleles 1.470 0~1.988 3 and number of effective alleles 1.196 1~1.203 4 in each group with 29 SSR markers.（2）There was no significant difference in genetic diversity index between control group and selected group which had more than 15 seedlings.（3）Numbers and changes（increase or decrease） of rare alleles in each group were also analyzed.It reveals that population sizes effected the number of rare alleles significantly,and the numbers decreased with less individuals.The suitable population sizes for wild pear conservation should be above 15 individuals.