120份欧美玉米自交系的遗传多样性分析

Genetic Diversity Analysis of 120 European and American Maize Inbred Lines

为了拓宽黄淮海区玉米自交系的遗传基础,加快欧美优异种质的融入与利用,本研究利用SSR分子标记对120份来自美国和塞尔维亚及2份中国的玉米自交系进行遗传多样性和聚类分析。结果表明:29个多态性SSR标记共检测到115个等位位点,平均3.97个,位点多态性信息指数(PIC)平均为0.50,较好地揭示了自交系间的遗传多样性;观测杂合度(Ho)仅为0.03,表明参试自交系遗传稳定、纯合度高;美国SS、美国NSS、塞尔维亚和中国骨干自交系4个群之间相比,美国NSS群的等位位点数(3.55)、Shannon信息指数(0.93)最高,而塞尔维亚群的有效等位位点数(2.37)最高,表明美国NSS和塞尔维亚自交系群比其他两个群遗传多样性高;4个自交系群间的遗传距离介于0.1403~0.4695之间,美国NSS群与美国SS群、塞尔维亚群之间较小(0.1419,0.1403),与中国骨干自交系群之间最大(0.4695),4个群的遗传一致度介于0.6253~0.8691之间,美国NSS群与美国SS、塞尔维亚两个群之间的遗传一致度较高,表明美国与塞尔维亚自交系之间基因交流频繁,亲缘关系较近;聚类分析将122份玉米自交系分为9大主要类群,美国SS种质、NSS种质自交系被明显的区分开,并且SS种质被分为2个主要类群(Ⅰ和Ⅸ),NSS种质被分为6个主要类群(Ⅱ-Ⅶ),来自塞尔维亚的材料分散在美国NSS种质类群。本研究结果为来自欧美的自交系在玉米育种中合理利用提供可靠依据。

To increase the genetic diversity of maize inbred lines and accelerate the use of imported elite germplasm resources,122 maize inbred lines from the United States,Serbia and China were subjected to analyze the genetic diversity and the phylogenetic analysis by using SSR molecular markers. A total of 115 alleles was detected by29 polymorphic SSR markers,with an average of 3. 97 alleles per SSR marker and with an average polymorphic information content（ PIC） of 0. 50,suggesting relatively high genetic diversity within this population. The observed heterozygosity（ Ho） was 0. 03 indicating the high genetic stability and homozygosity. Within sub-populations,the allele number（ 3. 55） and Shannon＇s information index（ 0. 93） in the American NSS group were the highest and the number of effective alleles（ 2. 37） in the Serbs group was the highest that suggested higher genetic diversity in groups of American NSS and Serbs,in contrast to the other two groups. The genetic distances among the four groups ranged from0. 1403 to 0. 4695 with being the largest genetic distance between American NSS and Chinese inbred lines and with being relatively smaller（ 0. 1419,0. 1403） between American NSS and American SS or Serbs. The genetic consisten-cy of the four groups ranged from 0. 6253 to 0. 8691. The higher genetic identity among the groups of American NSS,American SS and the Serbs indicated that the genetic exchanges between American and Serbia inbred lines are frequent and their genetic relationship is relatively close. The clustering analysis showed that 122 maize inbred lines could be divided into 9 major groups. Two groups of American SS and NSS were clearly distinguished. The American SS was further divided into 2 subgroups（Ⅰand Ⅸ）. The American NSS was divided into six subgroups（ Ⅱ-Ⅶ）,while the inbred lines from Serbia are dispersed in the NSS groups. Thus,this study provides a molecular basis for better use of maize inbred lines from the United States and Serbia in maize breeding.