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放牧对草地植物种群遗传与进化产生重要影响,本研究利用SSR分子标记对4个不同放牧强度下垂穗披碱草种群遗传多样性进行研究,试验地选择在甘肃省甘南自治州玛曲县的阿孜试验站,利用8对多态性强的SSR引物对不同放牧压力下4个居群的800个个体基因组进行检测,每个位点的有效等位基因数在1.2267~1.9976之间。利用popgene分析发现不放牧垂穗披碱草种群遗传多样性最高,在3种不同放牧地,中等放牧强度的遗传多样性指数较高,其次为重牧,最后为轻度放牧。在不同放牧干扰下的4个垂穗披碱草种群的遗传分化系数为0.5168,基因流Nm=0.2337,说明4个种群的遗传变异主要发生在种群之间。从种质资源保护角度来讲,不放牧对于垂穗披碱草种质资源的保护是有利的;从草地利用角度,中等放牧强度比较合理。
In this study, SSR markers were used to study the genetic diversity of Elymus natus populations under four different grazing intensities. The genetic diversity of Elymus sibiricus populations was studied experimentally in Aze, Maqu County, Gannan Autonomous Prefecture, Gansu Province Eight SSR primers with strong polymorphism were used to test the genomes of 800 individuals from 4 populations under different grazing pressures. The number of effective alleles per locus ranged from 1.2267 to 1.9976. Popgene analysis showed that the genetic diversity of the non-grazing Elymus sibiricus population was the highest. The genetic diversity index of medium grazing intensity was higher in the three different grazing areas, followed by heavy grazing, followed by mild grazing. The genetic differentiation coefficient of four Eulaliopsis diversifolia populations with different grazing disturbance was 0.5168 and the gene flow Nm was 0.2337, indicating that the genetic variation of the four populations mainly occurred among the populations. From the perspective of germplasm conservation, no grazing is beneficial to the protection of Elymus nutans germplasm resources. From the perspective of grassland utilization, the medium grazing intensity is reasonable.