SSR分子标记与玉米杂种优势关系的研究

以从CIMMYT引进的热带、亚热带玉米自交系和代表中国温带主要杂种优势群的玉米自交系为材料，利用SSR分子标记方法。从40对SSR引物中选取扩增清晰且多态性丰富的13对引物，在14份自交系中检测到72个等位基因变异，涉及到13个SSR位点，每个位点检测到2～8个等位基因，平均为5．53．每个位点的多态信息量(PIC)变化于0．11～O.84之间，平均0．65．依据14个自交系遗传相似系数，按类平均法聚类分析，将14个自交系分为6类，代表中国温带主要杂种优势群的玉米自交系被划分在不同类群中，聚类结果和系谱分析结果基本一致，因此用SSR技术可以划分杂种优势类群、但是根据自交系之间SSR分子标记数据估算的遗传距离，与杂种F1产量及其杂种优势相关不显著，不能预测杂种优势．

Studies on genetic relationship between the SSR molecular markers and the heterosis in maize

The experimental materials were tropical subtropical maize inbred lines from CIMMYT and temperate lines representing main heterotic groups in China .By SSR molecular markers,13 pairs of primers whose bands are clear and discrepant were selected out of 40. The 72 alleles identified were served as raw data for estimating genetic similarities among 14 lines, involving 13 loci. The average number of alleles per SSR locus was 5.53 with a range from 2 to 8. Polymorphic index content (PIC) values varied from 0.11 to 0.84 with an average of 0.65. The maize inbred lines tested were divided into 6 heterotic groups according to the results of SSR molecular markers. Cluster analysis by UPGMA placed the temperate lines in six clusters corresponding to the heterotic groups determined by their pedigree analysis. The coefficients between the genetic distance of SSR molecular markers and the heterosis of F_1 yield were not significant. Therefore, SSR can be used to divide heterotic groups, not to predict heterosis.