Abstract:

【Objective】 Screening of High Polymorphism SSR Primers for Classification of Heterosis Group in Maize (Zea mays L.).【Method】 A total of 160 pairs of SSR primers, including the core primers used in the past, which evenly distributed on 10 linkaged groups in maize, were selected, and then were amplified in DNA of 104 inbred lines.And then, based on the PIC values of the primers and their distribution on chromosome, 40 pairs, 30 pairs, 20 pairs and 10 pairs of high polymorphic primers were taken to establish 4 sets of new primer systems to classify the 104 inbred lines.【Result】 (1) Of the 160 pairs of primers, 63 were highly polymorphic, in which the highest PIC value was 0.762 that were close to or higher than that of core primers used in the past.The core SSR commonly used in the past retained only about 40% of the 63 primers.(2) In the 4 sets of primer systems, the classification of 40 pairs and 30 pairs of primer system were highly consistent with the groups of inbred lines.20 pairs of system were 90.5% consistent with that of 40 pairs of primers, and the system of 10 pairs of primers were only 81.0% consistent.(3) When 40 pairs of primers were used to classify 104 inbred lines, five groups were distinguished, that is, Reid, improved Reid, Lancaster, improved Huang and Lvda-Red-Cob, respectively, which was consistent with the heterotic groups used in our country at present.In each group, the most big distantly sub-group from main group consisted of the inbred lines derived from the hybridization between different groups.(4) Population genetic structure component of representative inbred lines of each group was single structure component, and the lines of subgroup were multi structure component.【Conclusion】 The decrease of polymorphism of some SSR primers was observed in the new inbred lines. The new system established by 40 pairs of primers has accurate classification function and could be directly applied to group classification.For the system of 20 pairs of primers, its accuracy is slightly lower, but its workload is halved, which is useful in the preliminary classification of batch inbred lines.

Key words: maize; SSR primer; polymorphism; heterotic group; population genetic structure

摘要：

【目的】 研究玉米杂种优势类群划分高多态SSR引物筛选。【方法】 遴选均匀分布在玉米10个连锁群上160对SSR引物,在104份玉米自交系DNA中扩增,根据引物的染色体分布和PIC值,分别取40、30、20和10对高多态引物建立4套新引物体系,检测104份自交系的分类效果。【结果】 (1)160对引物中的63对引物带型稳定,多态性高,最高PIC值0.762 3,高于过去常用核心SSR引物,63对引物中过去常用核心SSR引物仅保留40%左右;(2)4套引物体系中,40和30对引物体系的分类结果与已知自交系类群高度吻合,20对体系与40对体系比较具90.5%一致性,10对体系与40对体系比较的一致性81.0%;(3)40对体系分类104份材料为5大类群,分别是瑞德、改良瑞德、兰卡斯特、黄改和和旅大红骨,与目前国内利用的优势群划分结果一致,也能鉴别出每个群中亲缘关系最远的亚群是相近群间二环系来源的混合基因型;(4) 各群的代表自交系是单一遗传结构成分,亚群是多遗传结构成分。【结论】 部分SSR引物的多态性在新自交系中会出现下降,建立的新的40对引物体系有精确的分类功能,可应用于类群划分,20对体系的分类精确性稍低,但检测工作量减半,在批量材料分类中有利用价值。

关键词: 玉米, SSR引物, 多态性, 杂种优势群, 群体遗传结构