Analysis Of Population Genetic Structure Of Maize And Heterotic Grouping

At present, it is increasing that the partition of germplasm population and classification indomestic corn inbred lines,which is bad for simplifing the heterotic pattern and improvingthe breeding efficiency. However, the methods simplify the heterotic patter and have largesignificance for maize breeding research that exploiting heterosis group classified andestablish the heterotic model correspondingly. In our study, six standard test species were useas a reference, to analyze the germplasm group relations of96maize inbred lines fromGansu Pingliang maize breeding station using SSR markers. The main results as follows:1.Through optimizing seed germination condition of maize, we found after soaking8-12hours in diluted double-or tri-nutrient solution that is best for seed germination and seedinggrowth, especially when the temperature of nutrient solution between30and40degrees.2.The DNA extracted of etiolated seedlings and seeds using CTAB and0.1mol/L NaOHsolution respectively, after compared and analyzed the two methods, the results indicated that rapid extracted DNA of maize grain is suitable for SSR analysis, which has less demanding on the quality of DNA, at the same time, the DNA can save a long time and the methods have a lots of advantages, such as fast, economical, safe and convenient. By contrast, the methods of CTAB need water bath and fully grinding in liquid nitrogen that CTAB methods extracted DNA from maize leaves or etiolated seeding. And not only that, the methods need toxic and volatile reagents, such as chloroform, isoamyl alcohol, isopropyl alcohol and so on. In addition, the procedure is complex and on harmful. However, the DNApurity of CTAB extraction is higher than NaOH solution methods, because it can reduce the impurities, including extraction,washing and other steps.3.The study was analyzed the genetic diversity of96maize inbred lines and six domesticcommon standard test, the primers come from the70loci distributed uniformly throughout themaize genome. After using UPGMA cluster analysis, the result indicated that102maize inbredlines divided into six subsets and merged into two large groups, there are SS (Ludahonggu, PA,Reid) and NSS (PB, Siping head, Lancaster) respectively. The Structure2.3.1software was alsoused to divided heterotic patterns for further verifying the accuracy of the target groups, using K (k) to determine the most suitable value of K and we found the most appropriate K is6, whichmean the target group hav e six subsets. The population genetic structure was assessed usingQ-matrix generated by software; it indicated that the test material have213allelic variants andthe average number of allele per SSR locus was3.610with a range from2to7. Thepolymorphism informa tion content (PIC) for the SSR loci v aried from0.245to0.846with anaverage of0.614. Genetic simil arities among thematerials in this study ranged from0.282to0.882wi th an averageof0.670.