摘要
[Objective] This study aimed to investigate the genetic variation of wild and cultivated populations of Castanopsis hystrix. [Method] Genetic variation of five wild populations and three cultivated populations of Castanopsis hystrix, was investigated with ISSR-PCR amplification. Totally, 151 individuals were selected and analyzed by amplification using nine pairs of ISSR primers screened. [Result] Each primer pair produced 7-20 bands and 122 polymorphic bands were obtained. At population level, ISSR diversity in the wild populations (P=59.84%, HPOP=0.182 7, I=0.285 6) was higher than which in cultivated ones (P=54.87%, HPOP=0.136 6, and I=0.219 8). The genetic differentiation coefficient among wild populations (GST) was 0.99. The similar population structure was found in three cultivated populations (GST=0.127 5). According to the UPGMA cluster analysis, the genetic distance among wild populations became larger with the increase of geographical distance. [Conclusion] Compared with other seed plants, with either a similar life history or various breeding system attributes, relatively low level of genetic diversity was observed in these five wild populations, which was caused by population size reduction and habitat fragmentation related to human activities. The formation of population structure may be explained by the species’ breeding system.
[目的]调查红锥天然群体和栽培群体的遗传分化状况。[方法]以广东、广西、福建、云南、海南的5个红锥天然群体和广西的3个种源的红锥栽培群体为供试材料,用筛选出的9对ISSR引物,对8个群体共计151个个体进行ISSR分析。[结果]每对ISSR引物扩增出7～20条条带,共得到122条多态带。红锥天然群体在种群水平的多态带百分率P为59.84%,Nei基因多样性指数Hpop为0.1827,Shannon多样性指数(I)为0.2856,高于红锥栽培群体(P=54.87%,HPOP=0.1366,I=0.2198)。群体特异带及群体间共有带的差异与分布揭示了群体间的遗传差异及相似性,红锥天然群体遗传多样性主要存在于群体内,群体间的遗传分化系数Gst为0.99。在红锥的3个栽培群体中发现了类似的群体遗传结构(GST=0.1275)。UPGMA聚类分析结果表明,红锥天然群体间的遗传距离有随地理距离跨度增加而递增的趋势。[结论]红锥遗传多样性偏低可能与人为干预和环境破坏导致的种群缩小及生境片段化等因素有关;红锥种群遗传结构的形成则与其自身繁育机制密切相关。
基金
广西科技厅攻关项目"红锥良种选育与丰产栽培模式研究"(桂科攻10100012-3)
广西林科院基本业务费项目"红锥群体遗传学研究"(林科200901)
广西林科院基本业务费项目"红椎组培再生体系建立的研究"(林科201218)~~
