基于ISSR重庆秦巴山区优选核桃的遗传多样性分析

An ISSR-Based Analysis of the Genetic Diversity of Walnut (Juglans regia) Germplasms Primarily Selected from the Qinling-Daba-Mountain Region in Chongqing

为重庆秦巴山区核桃资源的进一步研究和利用提供参考,从重庆秦巴山区选出优良的核桃种质,并对其遗传多样性进行分析.对重庆秦巴山区城口、巫山、巫溪3县实生大龄核桃种质进行初步优选,利用ISSR技术对初步优选得到的种质进行遗传多样性分析.共选出114份较为优良的单株,从82条引物中筛选出12条条带清晰、重复性好的引物对114份供试材料的基因组DNA进行扩增.共扩增出位点61个,平均每条引物5.08个位点,其中多态性位点58个,多态率达95.08%,平均每条引物4.83个多态性位点.平均有效等位基因数(N_e)为1.657 8,Nei’s基因多样性指数(H)为0.373 2,Shannon信息指数(I)为0.547 1.通过聚类分析,种质之间遗传相似性系数为0.680~0.936,在0.750处,材料可分为13组.来自3县的3个核桃群体间遗传距离在0.032 7~0.046 2之间,遗传一致度在0.954 9~0.967之间,基因流(N_m)为11.197 5.供试材料具有较丰富的遗传多样性,而3个群体间并未产生明显的分化.该结果可为重庆秦巴山区核桃资源的进一步研究和利用提供参考.

In order to provide references for the research and utilization of walnut（Juglans regia）resources in the Qinling-Daba Mountain region of Chongqing,114 good walnut germplasms were screened out from Chengkou,Wushan and Wuxi counties of the municipality,and their genetic diversity was analyzed with the ISSR technology.Twelve primers with clear bands and excellent reproducibility were screened out from 82 ISSR primers to amplify the genome DNA of the 114 germplasms.A total of 61 loci were detected,averaging 5.08 loci per primer,and 58 loci showed polymorphism,with a polymorphic rate of 95.08%.Each primer had 4.83 polymorphic loci on the average.The number of effective alleles（Ne）was 1.657 8,Nei＇s gene diversity（H）was 0.373 2 and Shannon＇s information index（I）was 0.547 1.The genetic identity among the germplasms was between 0.680~0.936,and the materials were clustered into 13 groups at the point where the genetic identity was 0.750.The genetic distance of the 3 populations from the 3 counties was between 0.032 7~0.046 2,their genetic identity was between 0.954 9~0.967,and the gene flow（Nm）was 11.197 5.In conclusion,the materials in the experiment have relatively rich genetic diversity,but the 3 populations show no obvious differentiation yet.