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紫云英属于异花授粉植物,品种内个体基因型杂合,品种鉴定难度大。本研究以紫云英闽紫系列3个审定品种为材料,采用SSR标记进行取样策略对3个品种鉴别能力影响的研究。结果表明:(1)固定4对引物组合,从5~50进行梯度取样时,品种内的扩增位点总数、观测等位基因数趋于增多,但有效等位基因数、Shanon信息指数、遗传多样性指数增大到最大值后趋于下降,其中取样量为30时总体样品出现最大值;随着样品量的增加,品种间Nei氏遗传距离以及分子方差分析的品种间期望变异系数比例值(Phi PT)均呈减少趋势,但Phi PT值的置信度在增大;(2)固定品种的样品容量为30和50,再加入2对能扩增出在品种间形成频率差异的标记位点的SSR引物对,基于这6对SSR引物可以将参试的3个紫云英品种有效的区分,品种间期望变异系数比例值(Phi PT)提高且差异的置信度为极显著。主成分分析进一步表明:3个参试品种30个样品与50个样品的散布状况基本一致。对紫云英取样策略的研究表明:为提高对参试品种的鉴别能力,样品取样量以30株为宜,即达到较佳鉴别效果又降低分析成本。
Astragalus belongs to cross-pollination plants, heterozygous within the individual genotypes, identification of varieties difficult. In this study, three validated varieties of Astragalus purpurea series were used as materials, and SSR markers were used to study the effect of sampling strategy on the discrimination of three cultivars. The results showed that: (1) Four pairs of primer combinations were fixed. When the gradient was sampled from 5 to 50, the total number of amplified sites and the number of observed alleles tended to increase. However, the number of effective alleles, Shanon information index, When the sample size was 30, the total sample appeared the maximum value. With the increase of the sample size, the Nei’s genetic distance between cultivars and the expected variance coefficient of molecular variance analysis (Phi PT) showed a decreasing tendency, but the confidence of Phi PT value was increasing. (2) The sample size of the fixed species was 30 and 50, and two additional pairs of markers were able to amplify the frequency differences among cultivars Based on these six pairs of SSR primers, the three cultivars of Astragalus sinicus were effectively distinguished, and the ratio of expected value of coefficient of variation (Phi PT) among cultivars was increased and the confidence of the difference was extremely significant. The principal component analysis further showed that the distribution of 30 samples and 50 samples of 3 tested varieties was basically the same. The study on the sampling strategy of Astragalus sinicus showed that in order to improve the ability to distinguish the tested varieties, the sample size of the sample should be 30, which means that better identification results and lower analysis costs.