板栗群体的遗传多样性及人工选择的影响

The Genetic Diversity of Castanea mollissima and the Effect of Artificial Selection

利用水平板淀粉凝胶电泳技术对板栗９个群体１１个种同工酶系统的１２个酶位点进行分析，结果表明板栗（Ｃａｓｔａｎｅａｍｏｌｉｓｉｎａ）为多态性物种，遗传变异水平较高，其多态位百分率为７１．３％，每个位点的等位基因平均数为２．２７，平均期望杂合值为０．３４６；总的基因多样性中，８９．３％发生于群体内，各群体之间的遗传距离为０．０１０～０．１７７；对各等位基因频率进行ＰＣＡ分析，筛选出较合适的基因标记位点及构建了板栗遗传结构的空间变异模式。在综合前人研究的基础上，初步探讨了人工选择对板栗遗传多样性的影响。

Allozyme genetic variability in 9 populations of Castanea mollissima was investigated using starch gel electrophoresis at 12 loci coding for 11 enzyme systems. The level of genetic polymorphismand population differentiation was greater in C. mollissima than was usual for an outbreeding species, with the proportion of polymorphic loci (P) 71.3%, average number of alleles (A) 2.27, average expected heterozygosity (He) 0.346. About 89.3% of the total genetic variation was partitioned within populations. The Nei's genetic distance ranged from 0.010～0.177. Except for these, a principal components analysis of the data based on allelic frequencies revealed a spatial pattern of genetic variability in Chinese chestnut and provide some data about selecting enzyme marker. Based on previous research, the effect of artificial selection on the genetic diversity of C. mollissima was also studied and it could be inferred that the southwest area of China was the possible center of the genetic diversity.