黄山钓桥青冈种群的交配系统与近交衰退

MATING SYSTEM AND INFERRED INBREEDING DEPRESSION OF A CYCLOBALANOPSIS GLAUCA POPULATION IN DIAOQIAO,HUANGSHAN

采用垂直板型不连续聚丙烯酰胺凝胶电泳检测了黄山钓桥青冈种群的遗传变异、交配系统及近交衰退程度。黄山钓桥青冈种群维持有中等程度的遗传变异，多态位点百分比和期望杂合度分别为５０％和０．１８１４。采用ＰＯＤ－２、ＥＳＴ－１和ＥＳＴ－２等３个多态位点，利用ＭＬＴ程序估计的花粉库和母株基因频率之间存在一些差异，可能是由于成熟个体花粉产量不同和种群内个体非随机分布造成的。单位点杂交率平均为０．３９２，略高于多位点联合估计的结果（０．３３２），表明青冈为混合交配类型。虽然种群的自交率较高，然而近交系数（０．０４６±０．０６４）与０无显著差异。根据电泳数据计算的近交衰退δ＝０．９５４，表明钓桥种群经历了严重的近交衰退。分析表明近交衰退发生在幼苗至成熟之间，也可能在开花与结实期。

Vertical slab polyacrylamide gel electrophoresis was used to examine the genetic variability,mating system and to infer the level of inbreeding depression of a Cyclobalanopsis glauca population in Diaoqiao,Huangshan. Moderate genetic variation was found in the population which polymorphic loci percentage and expected heterozygosity were 50% and 0.1814, respectively. Three polymorphic loci, POD 2,EST 1 and EST 2, were used to estimated gene frequencies and outcrossing rate utilizing MLT program.Difference was observed on the estimated gene frequencies among maternal plants, pollen pool and seed pool,which might be the results of differential pollen products and the nonrandom distribution of individuals. Mean single locus outcrossing rate was 0.392 and multilocus outcrossing rate was 0.332, indicating a mixed mating type. Inbreeding coefficient was 0.046±0.064 though the selfing rate larger than 60%. The inferred inbreeding depression from electrophoresis data was 0.954, and showed that the Diaoqiao population of C.glauca sufferred serious inbreeding depression. Detail analysis suggests that the inbreeding depression might occur during the period of seeding and adult stage or of flowering and seed filled stage.