Application Of SSR Molecular Marker In Genetic And Breeding Of Maize

The 34 maize inbred lines in this paper were from Maize Research Center Inner Mongolia Academy of Agricultural Sciences and other places. 90 cross combinations were designed with the method of incomplete diallel team and correlation analysis on the materials was carried out, according to the total value of combining. Genetic distances of the 34 inbred lines were researched with SSR molecular marker technology, based on the 16 field characteristics of inbred lines. Some higher polymorphic SSR primers in maize inbred lines were selected. Results of classification methods were compared. The results were as follows:1. Cluster analysis of the 34 maize inbred lines was carrried out, based on the 16 field characteristics of them, resulting in 4 groups. The result was similar to the line relationship of those materials.2. Heterosis groups of the 34 inbred lines were divided by SSR molecular marker technology. The variation of 45 alleles was found out by 20 pairs of SSR primers. Each pair of primers screened out 5～11 alleles, with the average of 7.5 alleles, for every pair of primers. The PIC ranged from 0.758 to 0.888, with the average of 0.826.3. Based on the SSR finger print, the 34 maize inbred lines were divided into 4 groups with Word's methods. 6 germplasms were classified into group 1, 8 into group 2, 7 into group 3 and 13 into group 4. The clasification results were basically indentical to those based on geographic origin or germplasm lineage.4. The materials can be divided with both methods, with similar results. SSR markers of genetic distance reached a significant level with specific combining ability in F1 and the relevance of yield per plant. So it is practical that the heterosis groups were divided with SSR molecular marker technology.5. A set of opitional SSR-PCR system was built. 1 minutes of pre-denaturation at 93℃. 1 minutes of denaturation at 93℃. 1 minutes of annealing at 56℃～65℃(depending on the materials). 2 minutes of extension at 72℃. 30～35 cycles(depending on different materials). 2 minutes of extension l at 72℃. 5 minutes of final Re-extension at 72℃.6. Some new breeding inbred lines were divided into heterosis groups, and some higher combinations were found out. Those results provided the theoretic base for the further usage of the materials.