用遗传标记监测不同环境和经营措施下的加勒比松森林群体遗传动态

Monitoring genetic dynamics of Caribbean pine populations under different environments and management activities using genetic markers

对古巴加勒比松的 6个群体 (包括天然林、采伐林、母树林和种子园 )进行了同功酶分析 ,根据 5个酶系统 8个位点的同功酶数据 ,对各群体交配系统以及群体遗传变异和结构进行了分析。天然林、种子园和母树林的多位点异交率和绝大多数单位点异交率都和完全异交无显著差异 ,过渡采伐的松树岛群体多位点异交率显著小于完全异交 ,而只有一半单位点异交率显著小于完全异交。而且该群体单位点平均异交率和多位点异交率均低于其它 3个群体的估计值。采伐群体中同功酶变异和基因多样性与天然林群体 JAG的相似 ,但低于其它群体 ,其近交系数较大 ,但小于天然林 MAN和中国栽培群体的近交系数。中国引种栽培群体无论是同功酶变异还是基因多样性都显著高于古巴群体 ,与所有古巴群体的遗传距离都显著大于古巴群体之间的遗传距离。结果表明过度采伐导致群体自交程度增加 ,营建种子园可有效减少近交。自然分布区以外的引种栽培群体遗传变化最大 ,无论遗传变异和基因多样性都比参试其它群体大。

Isozyme analysis of seeds collected from natural and managed populations of the tropical pine, Pinus caribaea var caribaea , was used to assess mating systems and population genetic structure By comparing the genetic parameters of the managed with the natural populations, possible impacts of changed growing condition on population genetic dynamics were detected Six populations (consisting of 3 natural populations, 1 managed seed stand and 1 clonal seed orchard in Cuba and 1 plantation population in China) were assayed with 5 enzyme systems and 8 loci In all populations except the over logged island population, both single and multi locus outcrossing rates did not significantly differ from the complete outcross ( t =1) The multi locus outcrossing rate and half of the single locus outcrossing rates of the over logged island population were smaller than the complete outcross Both the average single locus outcrossing rate and the multi locus estimate were significantly smaller than that of the other three populations Isozyme variation and gene diversity of the over logged population were found similar to that of the natural population JAG, but lower than of the other populations The inbreeding coefficient in the over logged population was larger than in other populations except the two populations of MAN and Chinese plantation The population of the Chinese plantation was exceptionally different from the Cuban populations by displaying significantly larger isozyme variation and gene diversity The genetic distances between the Chinese population and the Cuban populations were significantly larger than that among the Cuban populations Results indicated that over logging caused the increase of inbreeding and that establishment of well designed seed orchard can effectively reduce inbreeding Given the changed growing condition and closely related neighboring species, the population of the Chinese plantation may have undergone several possible processes, such as bulking of seeds of different taxa or hybridization with related species (varieties)