栗杂交F1代SSR标记遗传多样性分析

Genetic Diversity of F Hybrids of Chestnut Based on SSR Markers

为深入了解栗属植物种内、种间杂交F1代群体遗传多样性和变异规律,以及不同亲本遗传效应和配置方式对杂交F1代的影响,以锥栗种内、锥栗和板栗种间9个杂交组合235份F1代单株及其亲本为材料,利用32对高多态性栗属SSR标记对其基因组DNA进行PCR扩增和毛细管电泳,统计数据并进行遗传参数、分子方差、UPGMA聚类和PCA分析。结果表明:32对SSR引物在235个子代中共扩增出278个多态性位点,平均观测等位基因数8.69个,Shannon’s多样性指数(I)、基因遗传多样性(Hs)和基因流(Nm)平均值分别为1.3707、0.6574和1.5951,遗传分化系数(Fst)显示杂交F1代85.18%的变异存在于组合内;不同组合Shannon’s多样性指数范围为0.8816~1.1317,显示其子代均存在丰富的遗传多样性,且子代遗传多样性水平受不同父、母本遗传效应以及亲本配置影响;分子方差分析表明栗杂交F1代群体遗传变异主要来源于组合内(78.06%),与遗传分化系数结果较为一致;不同杂交组合遗传距离和UPGMA聚类显示,具有相同亲本的正反交组合C3和C5遗传距离最近,最先聚到一起,其次是具有相同母本或相同父本的组合,分别聚到一起;杂交子代PCA散点图进一步验证了杂交组合聚类分析结果,同一组合内或遗传距离较近的组合多数子代能聚到一起,同时,不同组合子代又存在交叉重叠现象,说明存在较为广泛的基因交流,且子代分离现象明显。

In order to further understand the genetic diversity and variation of F1 population in intra-specific and inter-specific hybrids of chestnut,and the influence of genetic effects and configuration of different parents on F1 generation,the genome DNA of 235 F1 hybrids and their parents were amplified by PCR and analyzed by capillary electrophoresis with 32 pairs of SSR markers,and then the genetic parameters,molecular variance,UPGMA clustering and PCA analysis for the statistical data were performed. Two hundred and seventy-eight polymorphic loci were amplified by 32 pairs of primers in the 235 progenies;and the average number of alleles was 8.69;the average value of Shannon’s diversity index(I),genetic diversity index(Hs)and gene flow(Nm)were 1.3707,0.6574 and 1.5951,respectively;the genetic differentiation coefficient(Fst)showed that 85.18% of the variation of F1 generation existed in the cross combination. Shannon’s diversity index of different combinations ranged from 0.8816 to 1.1317,indicating that there were abundant genetic diversity in their offspring,and the genetic diversity level of those offspring were affected by the genetic effect of different parents and the configuration of parents. The results of molecular variance analysis showed that the genetic variation of F1 hybrid population mainly came from the combination(78.06%),which was consistent with the result of genetic differentiation coefficient. The genetic distance and UPGMA clustering of different hybrid combinations showed that C3 and C5,which had the same parents,had the closest genetic distance and got together first,followed by the combination with the same female parent or the same male parent,got together respectively. The PCA scatter plot of hybrid progenies further verified the result of cluster analysis of hybrid combination. Most progenies of the same hybrid combination or the combinations with relatively close genetic distance could gather together. At the same time,there was cross overlap phenomenon in different combinations,which indicated that there was more extensive gene exchange among them,and the phenomenon of offspring separation was obvious.