微卫星标记分析水稻地方品种30年的遗传变异

Analysis of genetic variation in rice paddy landraces across 30 years as revealed by microsatellite DNA markers

为揭示水稻(Oryza sativa)地方品种30年的遗传变异状况,文章通过60个SSR标记,对元阳哈尼梯田农户在20世纪70年代种植的6个(简称"过去的品种")和近10年间种植的对应6个(简称"当前的品种")代表性水稻地方品种进行检测。结果表明,共检测到159个等位基因(Na),等位基因数1～4不等,当前的品种较过去的品种减少7个等位基因。平均每个标记检测到的等位基因数(Na)、有效等位基因数(Ne)、基因型多样性(H′)和位点多态信息含量(PIC)4个指标均为过去的品种高于当前的品种,分别是(Na)为2.567>2.450,(Ne)为2.052>1.968,(H′)为0.768>0.722,(PIC)为0.469>0.439。基于60个SSR标记,过去6个品种间的遗传相似性系数(GS)平均值为0.437,变幅为0.117～0.667,而当前6个品种间平均值为0.473,变幅为0.200～0.700。总的说来,水稻地方品种经过30年自然和人工选择,遗传多样性降低,不同品种存在等位基因大小的差异程度不同。

To reveal the genetic variation of rice paddy landraces across 30 years, we compared the genetic variation of between 6 paddy rice landraces grown in Yuanyang Hani＇s terraced fields in Yuanyang County, Yunnan Province in the 1970s （past-grown landraces） and 6 paired ones that have been grown during the past decade （current-grown landraces） using 60 SSR markers. The results showed that one to four alleles were amplified in 60 loci and 159 alleles in all the land- races tested. The number of alleles from the current-grown landraces decreased by 7 alleles compared to the past-grownlandraces. The average number of alleles （Na）, effective number of alleles （Ne）, locus polymorphism information content （PIC）, and genotype diversity （H） of the past-grown landraces were higher than those of the current-grown landraces, with Na of 2.567〉2.450, Ne of 2.052〉1.968, PIC of 0.469〉0.439, and H＇ of 0.768〉0.722. The average genetic similarity coeffi- cient （GS） of the past-grown landraces was 0.437 with a range from 0.200 to 0.700 based on the 60 SSR markers, and the average GS of the current-grown landraces was 0.473 with a range from 0.117 to 0.667. In conclusion, the genetic diversity in current-grown landraces was decreased compared to the past-grown landraces, and the degree of variation in some of the allele locus varied in different rice landraees as a result of 30 years＇ natural and artificial selection.