Genetic Diversity And Population Structure Analysis Of Different Maize Inbred Lines Using SSR Markers And Agronomic Characters

Understanding of genetic diversity and population structure analysis of different maize inbred lines is crucial for breeding and germplasm research in maize.Genetic diversity and population structure of 211 maize inbred lines was studied using 100 SSR primers and 27 agronomic characters.The results could provide useful message for their efficient utilization and genetic improvement in further maize breeding.The main results were as follows:1.Among all the 211 inbred lines,a total of 376 alleles were detected across all the 100 SSR loci.The number of alleles per locus ranged from 2 to 11,with the range of polymorphic information content(PIC)value from 0.20 to 0.86,and gene diversity among them was ranging from 0.21 to 0.77.2.All the 211 inbred lines were divided into six groups,groups A,B,C,D,E and F,according to GS=0.698.A dendrogram using UPGMA analysis showed that the clustering pattern was complex.This suggested that these inbred lines represented a broad range of maize germplasms.Respectively,groups A,C and E were the three major groups among which 200 inbred lines were included,accounting for 94.79 %.For groups A1~A6,8,17,1,1,2 and 2 lines were included according to GS(A)=0.760,respectively.For groups C1~C11,17,6,32,2,5,21,2,3 and 3 lines were included according to GS(C)=0.724,respectively.For groups E1~E6,23,2,9,5,18 and 6 lines were included according to GS(E)=0.712.3.The value of genetic distances(GDs)ranged from 0.09 to 0.46,with an average value of 0.25.The highest value of GDs was 0.46 between group D and group F,and the lowed value of GDs was 0.09 between groups E and C.These results reflected that the GDs was significant differences between six groups.4.Combined variance analysis for 27 agronomic traits among 211 maize inbred lines showed that all traits were significant or highly significant different among maize inbred lines.The coefficient of variation(CV)was difference among different traits,with the highest CV value of 103.8% for the bare tip length,and the lowest CV value of 1.78% for starch content.These results indicated that these maize inbredlines reflected rich diversity.UPGMA analysis showed that these maize inbred lines were divided into eleven groups among 27 according to the agronomic traits by using SPSS software.5.Compared the clustering analysis of SSR markers with agronomic characters in different maize inbred lines,poor consistency was observed.However,the clustering analysis of agronomic characters was essential to genetic improvement of agronomic characters for inbred lines.6.Our result verified the five corresponding heterosis patterns Lancanster×LRC,improved Reid×TSPT,TSPT×Reid,Reid×Lancanster and Reid×PB.Three major groups(groups A,C and E)and two core heterotic types(groups C × C and groupa A× E)were consistently revealed according to the representative lines,the genetic differences among different groups and between pairs of parental lines of hybrid for22 important commercial hybrids.Two high-oil and a popcorn line were distinctly classified in groups E6 and A3,respectively.