Genetic Diversity Revealed By SSR Molecular Markers Among Main Maize Inbred Lines And Hybrids In Shaanxi Province

Researched on genetic basis of maize germplasm was the work key point of maize breeding.Identificated genetic character of maize materials scientifically had vital significance to identification of germplasm quality, evaluation of genetic germplasm and protection of varieties' rights.The complete approach to solve this problem is to enhance and improve the germplasm with concrete objectives based on heterotic group and pattern studies. Simple sequence repeats(SSRs)markers were used to establishe the standard DNA finger printing of elite maize inbred lines of Shaanxi province, and study on the genetic diversities of 23 main maize inbred lines and 26 main maize hybrids in Shannxi Province respectively.The main result were as follows:1. Using a set of SSR technique which including total DNA extraction,PCR,enaturing polyacrylamide gel electrophoresis(PAGE) and silver staining, 33 primers were selected out of 100 pairs, which gave clear, stable, repeated, polymorphic amplification profiles as the core primers of maize inbred lines in Shaanxi province.2. On the 33 SSR loci, a total of 162 alleles had been detected in these inbred lines. At each SSR locus, 2 to 8 alleles could be detected, with a average of 4.91, the polymorphism information content (PIC) for all the SSR primers varied from 0.464 to 0.884.Established digital fingerprint of 23 main maize inbred lines, the appearance probability was 1.08×10-22. This method could be applied to analyze purity of maize inbred lines.3. Twenty-three inbred lines were classified into four groups by UPGMA (unweightied pair group method agrithmetic average) based on GS (genetic similarity) from SSR fingerprinting data, which included improved Reid, Lancaster, Tangsipingtou and Ludahongguzi group. The classification accorded with the heterrotic groups determined by pedigree analysis. In the four groups,improved Reid and Tangsipingtou contained 13 and 6 inbred lines respectively, it shows that the genetic basis was rich in the two groups.4. Twenty-nine SSR primes were used to detect genetic diversity among 26 maize hybrids,which were used widely in Shaanxi province. Twenty-nine SSR primers selected from 100 primers produced 148 polymorphic amplified fragments.The average number of allele per SSR locus was 5.1 with a range from 2 to 9.The average polymorphism information content(PIC) was 0.690.Genetic similarities among the 26 maize hybrids ranged from 0.520 to 0.851 with an average of 0.674,maize hybrids with one common parent have high genetic similarity coefficients.5. Twenty-six maize hybrids were classified into fives groups by UPGMA, the mian used heterotic patterns were improved Reid×sipingtou, sipingtou×lines and lines×synthetic variety, which accorded with pedigree analysis. It indicated that it was feasible to study on genetic diversity of maize hybrids through screening core primers by SSR.