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以 12 2份野生稻和 75份栽培稻在 4 4个 RFL P位点的多态性为资料 ,采用逐步聚类法和分组随机法 ,按原始样本的 50 %、 2 0 %和 10 % ,分别构建初级核心样本、次级核心样本和核心样本 ,用多态位点数 ( Np)、等位基因数 ( Na)、基因型数 ( Ng)及平均基因多样性 ( Hs)等参数 ,检测其遗传多样性。结果表明 ,初级核心样本的 Np、 Na和 Ng分别达到原始样本的 90 %、 90 %和 80 %以上。次级核心样本的Np、 Na、 Ng仍分别可达原始样本的 90 %、 80 %和 75%。核心样本的 Np可达原始样本的 90 % ,而 Na和 Ng下降幅度大 ,分别相当于原始样本的 65%和 55%。无论哪一级核心样本 ,栽培稻遗传多样性的减少幅度比野生稻小。比较逐步聚类法和分组随机法表明 ,逐步聚类法构建的核心样本比分组随机法更能保持较大的遗传多样性。作者认为检验核心种质遗传多样性的首选参数是等位基因数
Based on the polymorphism of 12 2 wild rice cultivars and 75 cultivated rice cultivars at 4 4 RFL P loci, the data of 50%, 20% and 10% of the original samples were obtained by stepwise clustering and grouping randomization. The primary core samples, the secondary core samples and the core samples were constructed respectively. The polymorphisms were detected by using the parameters of Np, Na, Ng and Hs Genetic diversity. The results showed that the Np, Na and Ng of the primary core samples reached 90%, 90% and 80% respectively of the original samples. Secondary core samples still have Np, Na and Ng up to 90%, 80% and 75% of the original sample, respectively. The core sample has a Np up to 90% of the original sample, while the Na and Ng declines by as much as 65% and 55% of the original sample, respectively. No matter what level of core sample, the reduction of genetic diversity of cultivated rice is smaller than that of wild rice. The comparison of stepwise clustering method and grouping random method shows that the core sample constructed by stepwise clustering method can maintain a larger genetic diversity than the grouping random method. The authors consider that the preferred parameter for testing the genetic diversity of core collections is the number of alleles