利用核心SNP标记划分辽宁省常用玉米自交系杂种优势群的研究

Heterotic Grouping by Core SNP Markers for Maize Inbred Lines Widely Used in Liaoning Province

利用3个密度的SNP标记对44份玉米自交系进行杂种优势群划分,包括8份对照自交系和36份辽宁省常用育种自交系。利用56k玉米芯片共筛选得到了46 899个高质量的SNP标记,作为高密度SNP标记划分杂种优势群,然后筛选1 008、101个SNP标记分别作为中密度和低密度SNP标记用于分群。结果表明,部分自交系的遗传相似度达到90%以上,不宜作为不同自交系进行育种应用。3个密度下的SNP标记都有效地将待测玉米自交系划分为4个杂种优势群,分别为瑞德群、兰卡斯特群、旅大红骨与塘四平头混合群以及类PH4CV群。对比高密度SNP标记,利用中低密度SNP标记划分的杂种优势群内部分自交系间的遗传距离发生变化,不能精确解析杂种优势群群内自交系的亲缘关系。划分杂种优势群可以采用中低密度的SNP育种芯片;群内自交系亲缘关系的区分应该采用高密度SNP芯片。

In this study, 44 samples, including 8 representative inbred lines of classical heterosis groups and 36 popular inbred lines in maize breeding of Liaoning province, were grouped by three density groups of single nucleotide polymorphism（SNP）, respectively. A total of 46899 high-quality SNP markers obtained from 56k Maize Genome Array platform were used as the high-density group for heterosis grouping. Among them, 1008 and 101 core SNPs was selected as the medium-and low-density SNP groups for heterosis grouping, respectively. Then, some lines should not use as difference materials in breeding due to their genetic similarity was more than 90%. Cluster analysis with high-density SNP group classified the inbred lines into Reid, Lancaster, a mix group of Lvdahonggu and Tangsipingtou, and a like-PH4CV group. Similar results were both obtained in the cluster analysis with 1 008 and 101 core markers, however, the genetic distances between a few of the inbred lines changed. The results suggested that the low or medium-density SNP groups could economically and effectively separate heterosis groups, while the inbred lines relationships within group need the high-density SNPs group.