北京油松人工林遗传结构变异及与山西山系种群差异分析

【目的】本研究旨在揭示与阐明北京主要油松人工林种群的遗传多样性、遗传结构与亲缘关系,引种地对种群遗传结构及生长的影响,尝试追溯其可能的种源,为北京地区油松人工林培育与种质遗传管理提供参考。【方法】试验采用7对多态性高且扩增稳定的核基因组EST-SSR引物,以北京地区20世纪营造的油松人工林8个种群和皇家园林的古油松3个种群及山西省五大山系的油松种群为试验对象,分析种群遗传多样性、遗传结构和种群间的遗传距离等。【结果】结果表明:3类种群中,北京人工林种群间遗传结构差异最大(FST=0.066),山西五山系群体间遗传结构差异次之(FST=0.033),古油松种群遗传结构差异最小(FST=0.023);北京油松人工林和古油松种群均偏离Hardy-Weinberg平衡,且呈现杂合子过剩状态,其中古油松种群杂合子过剩更多;在遗传距离0.020处北京人工林、古油松和山西五山系共16个油松种群聚为3类,各种群之间的遗传距离较近,遗传差异较小,相似程度较高;EST-SSR位点J10、J20、J42和J50在北京人工林、古油松和山西五山系中位点扩增频率差别大可用于未知种源的油松种群种源溯源。【结论】北京油松人工林种群较古油松种群有更丰富的遗传多样性和更大的遗传结构差异;外来种质在引入地胁迫生境下的适合度差异导致部分植株被淘汰,因此保留下来的种群遗传结构发生一定程度的改变;试验为后续北京地区油松人工林的评价、培育和种质种源管理打下了基础。

Genetic structure variation of Pinus tabuliformis plantations in Beijing and the differences with Shanxi mountain populations

ObjectiveThe purpose of this study was to reveal the genetic diversity, genetic structure and genetic relationship of Pinus tabuliformis populations in Beijing, and to explore the impact of introduced land on population genetic structure and growth, and to provide references for the cultivation and germplasm resource management of P. tabuliformis in Beijing.MethodBased on 7 pairs of highly and stable polymorphically nuclear genomic EST-SSR primers, the population genetic diversity, genetic structure and genetic distance were analyzed among 8 P. tabuliformis populations planted in last century in Beijing, 3 ancient P. tabuliformis populations and 5 mountain populations from Shanxi Province of northern China.ResultThe genetic structure difference ( F_ST = 0.066) was the maximum among Beijing plantation populations, the second was population from Shanxi Province (F_ST = 0.033), and the lowest was ancient populations (F_ST = 0.023). Both of the Beijing populations and ancient populations deviated from Hardy-Weinberg equilibrium and showed heterozygote excess, and the maximum heterozygote excess was in ancient P. tabuliformis populations. All of the populations could be clustered into 3 categories when genetic distance was 0.020 based on genetic distance analysis, showing near genetic distances among different populations, the level of evolutionary divergence and genetic differentiation were relatively low. The EST-SSR loci site amplification frequency of J10, J20, J42 and J50 in Beijing populations, ancient P. tabuliformis and Shanxi populations showed significant differences, which could be used for source tracing for unknown provenances.ConclusionThe Beijing populations of P. tabuliformis have richer genetic diversity and higher genetic differentiation than ancient P. tabuliformis; some introduced provenances eventually phased out because of the difference in fitness under stress environment, resulting in the genetic structure has a certain amount of change for the retained population. Our study provides important theoretical foundation for the follow-up studies on the evaluation, cultivation and germplasm management of P. tabuliformis populations in Beijing.