Genome-Wide Association Analysis Of Main Agronomic And Resistance Traits In Maize Inbred Lines

Corn is an important food crop, animal feed and an industrial raw material, which all plays increasingly important role in the capital economy of the our country.Research on analyzing the genetic diversity of maize inbred lines and classifying the heterotic group and the model of heterosis which using to select the parents and improve, innovate, excavate and employ the good germplam cloud improve the efficiency of selecting the parent of hybrid and shorting the duration of breeding, which was the important basis of maize breeding.The materials of this study were inbred lines. Genetic distance obtain were used to classify the heterotic group of good maize germplasm and analyze and discuss the model of heterosis.In this study, a total of 371 maize inbred lines (181 representing the Areas of Northeast and North China and190 representing Huang-Huai-Hai growing region) were selected and used for genetic diversity. From these 371 lines,15 of main traits analyzed phenotype diversity.6771of SNP markers were used for genotyping of 371 maize inbred lines and analyzed population structure, association analysis which was on base of the whole genome screening, using haplotype analyze and selecting the excellent germplasm resources, objective to lay the foundations for inbred lines selected and breeding new varieties.The results of this study follow as:According to the results of statistical analysis of maize inbred lines, variation coefficients of traits were more than 10% except the silking stage、flowering stage and seeds moisture content in two growing region, variation coefficients of trait of smut was 197.65%、193.07% in those two growing region. Using normal testing,15 of main traits which obey normal distribution and abnormal distribution. The results show clearly that association analysis groups were riched in phenotypic variation.A total of 371 maize inbred lines were evaluated using 6771 SNP markers were identified the genetic similarity coefficient, the result indicated that the of genetic similarity coefficient the 371 maize inbred line was from 0.27-0.99, the average was 0.55, among the LH 205 and Mo 17 was 0.27. The average of genetic similarity coefficient in different varieties was from 0.384-0.583, the bigger Variation coefficients was 3.77%.Conclusion the genetic diversity of the population analyzed is much more ample.According to the genetic makeup of the maize inbred line, analyzing the population structure, the inbred line which was Q≥0.500 has been classified into subgroup,283 varieties have been classified into four subgroups, Group AA01 has 73 varieties, LeiZheng58 Group has 41 varieties, LeiBBO1Group has110 varieties, Lei Chang7-2 Group has 59 varieties. The cluster analysis showed that the 283 inbred lines could be divided into four subgroup,which correspond to the heterotic groups determined.According to the results of selection to perform association mapping of association of SNP loci, there were 24 strong association loci which were selected from the Areas of Northeast and North China, and 6 of those strong association loci were located on the Chromosome 6, agronomic characters were silking stage, flowering stage, smut and hundred grain weight. We evaluate the PZE-101063113which was located on Chromosome 6 associated with plant height and ear height; SYN26290 was located on Chromosome 10 associated with silking stage and flowering stage. We detected 22 strong association loci which were selected from the Areas of Huang-Huai-Hai region, on Chromosome 3, we detected strongest 5 association loci, the association mapping result of estimated value show that those association loci associated with plant height、silking stage、flowering stage and kernels per row. PZE-103035720 was located on Chromosome 3 which associated with silking stage and flowering stage.Few strongest association traits which were used to haplotype analysis had been an method for Inbred lines with traits of high yield、disease resistance and Precocity selection. 115 inbred lines which were more than 50% of selection index were from the Areas of Northeast and North China, which accouted for 31% of the all inbred lines. The selection index of D376-2-4-1-1-1-land LiMin33FM run up to 67%,188 inbred lines which were more than 50% of selection index were from Huang-Huai-Hai growing region, which accouted for 51% of the all inbred lines. The selection index of PH32-S411Sand A177 run up to 67%. This study which laid a foundation of germplasm base for breeding new varieties.