我国部分玉米自交系遗传关系和遗传结构解析

Analysis of Genetic Structure and Genetic Relationships of Partial Maize Inbred Lines in China

玉米自交系遗传关系和遗传结构的解析,对自交系类群划分和杂交组配具有重要的指导意义。本文选用玉米基因组的112个SSR标记对我国97个玉米自交系进行遗传关系和遗传结构分析,并评价了遗传距离聚类和模型聚类方法在玉米自交系遗传关系研究中的应用价值。结果表明,模型聚类方法更适于玉米自交系的遗传关系研究。解析自交系的遗传基础发现,各类群中均有大量自交系含有其他类群的遗传成分。根据模型聚类结果,97个自交系被划分为PB、Reid、塘四平头和旅大红骨4个类群。Reid群与旅大红骨群的遗传关系最近,与塘四平头群遗传关系最远。为了实现杂种优势模式的简化,4个类群可被简化为3大种质类群[A(旅大红骨群与Reid群)、B(PB群)、C(塘四平头群)],或2大种质类群[A(旅大红骨群、Reid群、PB群)、B(塘四平头群)]。研究结果为自交系的改良和利用及杂种优势模式确定提供了理论基础。

Knowledge about the population structure and relationships within and among maize inbred lines was important to improvement and utilization of maize inbred line.Distance-based cluster and model-based cluster methods were used to analyze the genetic structure and relationship of 97 maize inbred lines used in China with 112 microsatellite（simple sequence repeat,SSR） markers,evenly distributed over 10 chromosomes.Results showed that model-based cluster method was more suitable for maize inbred line clustering than distance-based cluster method,because the former could define the group of inbred lines more effectively than the latter.All inbred lines were grouped into four groups by model-based cluster method：Reid,Lüda red cob（LRC）,PB and Tangsipingtou（SPT）.According to the result of genetic structure component（Q-value）,numerous inbred lines in each group were overlapped in genetic component with the other groups.Reid group kept minimum Nei＇s genetic distance with LRC group,had most distant genetic relationship with SPT group.The results of genetic relationships among groups indicated that the four groups could be simplified into three（A：Reid,LRC;B：PB;C：SPT） or two（A：Reid,LRC,PB;B：SPT） potential heterotic groups.The defined population and the genetic component analysis of inbred lines provided the basis for improving the efficiency of hybrid breeding.