紫花苜蓿杂交后代遗传变异的AFLP分析

AFLP analysis of genetic variation for the hybrid progenies of alfalfa

利用扩增片段长度多态性(AFLP)标记对德钦苜蓿♀×Acrora♂杂交组合的杂交亲本与杂交F1代、F2代的遗传变异进行分析,结果如下:(1)36对引物中筛选出4对引物,共检测到199个扩增片段,其中,有172个多态性位点,多态性位点比率为90.5%,可以用于杂种后代遗传变异分析;(2)与杂交亲本比较,杂交F1和杂交F2代的Nei基因多样性指数(H)、Shannon多样性信息指数和有效等位基因数(Ne)发生了显著的变化,遗传多样性增大,杂交F2代遗传变异程度最高,说明F2代发生了较大的性状分离;(3)杂交后代的基因分化系数(Gst)为0.218,基因流(Nm)为0.874,表明杂交子代出现了较高的遗传分化;(4)杂交亲本及杂交后代遗传距离分布在0.128～0.284,其中,F1代与亲本的遗传距离最小,为0.128,而F2代与亲本之间的遗传距离最大,为0.284。表明F1群体变异较小,F2群变异较大。依据Nei′s遗传距离系统树图可以看出,在杂交子代中,F1代群体与亲本的系统发育关系更为接近。

AFLP molecular marker was applied to detect the genetic variation in the parents,F1 and F2 of the hybrid of Medicago sativa cv.Deqin（♀）and M.sativa cv.Acrora（♂）.The results showed that：1）4 primers were screened out from 36 AFLP primers to amplify the alfalfa genome DNAs of the materials effectively.Among amplified 199 sites,172 were polymorphic and the ratio of polymorphic loci was 90.5%,which proved that AFLP marker could be used to analyze genetic variation.2）In terms of Shannon＇s index,Nei＇s index and effective number of alleles,the genetic diversity of the parents was the lowest,and that of F2 was the highest.3）The gene differentiation coefficient of 0.218 and the gene flow of 0.874 of the hybrid progenies suggested that a higher genetic differentiation resided among F1 and F2.4）The genetic distance between parents and their F1 and F2 was ranged from 0.128 to 0.284.The smallest genetic distance of 0.128 occurred between the parents and F1 while the largest of 0.284 was detected between the parents and F2.The systematical cluster analysis showed that there was a closer phylogenetic relationship between parents and F1.