川渝地区地方和育成大豆品种SSR标记多样性分析?

利用基本均匀分布于大豆20条染色体的135对SSR标记，对232份包括6个地方品种地域亚群和1个育成品种亚群进行全基因组扫描。结果表明：所有的标记都有多态性，所有检测到的位点都是纯合基因型，说明所选用品种高度纯合，每个标记存在2～4个等位变异，平均2.66个。亚群多态信息含量变异范围0.2751-0.3165，整个群体为0.3208；亚群内Nei遗传距离变异范围0.325 8～0.359 4，整个群体为0.3711，说明川渝地区大豆遗传变异较小。亚群间的遗传一致度（GI ≥ 0.8862）较高，亚群间遗传距离（GD ≤ 0.1208）较小，地方品种亚群间遗传差异更小，育成品种亚群与自然地域亚群的遗传差异相对较大。亚群间基因分化系数（Fst）平均为 0.0722，基因流（Nm）平均为 3.214，说明不同亚群之间存在一定的基因交流。主坐标分析表明第一、二和三主成分分别解释总变异的4.97%、3.54%和3.33%。来自同一区域的品种资源基本聚集在同一亚群，聚类分析同样表明同一自然地域亚群品种资源虽不能完全聚集到同一个遗传类群中，但具有一定的聚集效应，说明川渝大豆品种资源遗传变异与地理位置有一定的关系。分子方差分析表明亚群内变异占总变异的97%，亚群间变异仅占总变异的3%。Mantel收敛分析表明地方品种自然地域亚群的遗传距离与所处的地理位置距离（纬度和海拔）呈显著的正相关关系（R2=0.723）。川渝地区大豆种质资源群体遗传丰富度不高，当前的育成品种未蕴含本地区所有遗传变异。

Diversity analysis of SSR markers of local and bred soybean varieties of Sichuan and Chongqing

A total of 135 pairs of SSR markers covering entire soybean genome were used to scan genome-wide of 232 varieties including 6 natural sub-populations and 1 breeding sub-populations. The genetic diversity and variation in and among sub-population, the source of molecular variance, genetic drift among sub-populations, between genetic distance of sub-populations and geographical coordinates were analyzed. The results showed that all markers were polymorphic and all detected loci were homozygous. The number of alleles in different loci ranged from 2 to 4, averaging 2.66 per locus. All varieties were highly homozygous. The variation of population polymorphic information content ranged from 0.2751 to 0.3165, and the whole population was 0.3208. The variation range of Nei genetic distance within the population was 0.3258-0.3594, and the whole population was 0.3711. The genetic variation of soybean in Sichuan and Chongqing area was relatively lower. The genetic identity among populations were higher (GI ≥ 0.8862) and genetic distances were lower (GD ≤ 0.1208), genetic differences of local varieties were smaller among populations, genetic differences between the cultivars and all local varieties were relatively higher. The average gene differentiation coefficient (Fst) among populations was 0.0722, and the average gene flow (Nm) among populations was 3.214. There was a certain genetic communication among natural populations. The principal coordinate analysis showed that the first, second and third principal factors were able to explain 4.97%, 3.54% and 3.33% of the total variation respectively. Which came from the same natural population were basically clustered in the same region. The cluster analysis of varieties also showed that varieties of the same natural population were not fully clustered in the same genetic group, but had a certain clustering effect. These showed that there was a correlation between the genetic variation of Sichuan and Chongqing soybean varieties and geographical location. The molecular variation analysis of variance showed that 97% of total variation was explained in the population variation, and 3% of total variation was explained among population variation. Mantel convergence analysis showed that there was a significant positive correlation between the genetic distance and geographical location (latitude and altitude) distance of the natural populations of local varieties (R2=0.723). Research showed that the genetic richness of soybean germplasm resources wasn’t high in Sichuan and Chongqing. The current breeding varieties didn’t contain all the genetic variation in the region. We need to further expand and introduce excellent genetic resources to enhance the utilization of local resources. A few improved varieties adapted to high altitude ecotype could be used in breeding by introducing a minority of genes adapted to high altitudes into excellent lines.