云杉天然群体基因分化与种质资源异地保存抽样策略

Gene Differentiation in Natural Population of Picea asperata and Sampling Strategies for Ex situ Germplasm Resource Conservation

采用聚丙烯酰胺垂直板凝胶电泳和水平淀粉凝胶电泳对云杉全分布区10个天然群体的300个个体进行酶电泳分析,研究天然群体的等位基因数量和频率分化,共测定8种酶系统,得到17个清晰酶位点和27个等位基因.10个群体检测到的等位基因数均值为24.7个(变幅为23～27个).据基因频率进行分类,检测到全域基因和广域基因数量分别为19个和7个,分别占总基因的70.37%和25.93%;特有基因只有1个,即铁布群体的Idh-2-C,占总基因的3.7%.10个群体基因频率的均值没有太大差异,相同位点的广域基因频率在群体间均存在差异.通过计算机模拟建立云杉天然群体种质资源保存的群体和群体内个体两个层次的基因捕获曲线.群体的等位基因频率与地理生态因子的相关分析表明:Fdh-2-B基因频率与生态梯度值呈显著负相关(r=-0.661 1*).构建了云杉天然群体核心种质保存的抽样策略,经综合分析,抽取全分布区内铁布、卓尼、阿坝、小金、热务沟、凤县和曲谷7个群体,每个群体保存25个拟式无亲缘关系的个体,可以保护云杉种内95%～99%的基因资源.

The number and differentiation of alleles of Picea asperata （PA） natural population were studied by means of horizontal sliceable starch gel electrophoresis and vertical slab polyacrylamid gel electrophoresis to analyze the isozyme variation of 300 individuals from 10 natural populations （30 individuals per population） in its natural distribution area. On the basis of analyzing the allozyme bands, 17 loci and 27 alleles of 8 enzyme systems were detected. The mean number of alleles determined from the 10 natural populations was 24. 7, ranging from 23 to 27. The number of essential alleles and widespread alleles were 19 and 7 respectively, accounting for 70. 37% and 25.93% of total number of alleles detected. There was only 1 rare allele detected in Tiebu population, i.e. , Idh -2 - C, accounting for 3.7% of all alleles detected. There was no obvious difference in allele frequencies among the 10 natural populations. However, there was some difference in essential allele frequencies at the same loci among the populations. Curve maps of gene capturing of isozyme marker at both population level and at individual level inside the population for germplasm resource conservation of Picea asperata（PA） natural population were established. It was showed by correlation analysis that there was a negative relationship （r = -0. 661 1^＊）between the gene frequency of Fdh -2 -B and the ecological gradient value. The sampling strategy for the core gene resource conservation of Picea asperata（PA） natural population was made. It was indicated that 95% -99% gene resources of Picea asperata（PA） natural population could be conserved effectively by sampling 7 populations from Tiebu, Zuoni, Arba, Xiaojin, Rewugou, Fengxian and Qugu in the whole natural distribution area and 25 individuals per population randomly.