| Maize(Zea mays L.)is the largest grain crop in China and is planted in a large area all over the world.Drought is the main factor limiting the growth of maize and reducing the yield of maize.Multi-parent Advanced Generation Intercross(MAGIC)is a new generation population for genetic mapping and breeding selection.The discussion on Genetic Breeding of maize magic population by means of genetics and genetic engineering is of great significance to cultivate maize varieties with rich genetic diversity,strong drought resistance and high yield.In this study,986 maize magic populations constructed by 16 parents were used as experimental materials to investigate the phenotypes of drought tolerance related traits.Then,48 K SNP chip was used for genotype analysis,combined with phenotypic data for genome-wide association analysis,and the significant loci related to drought tolerance traits were obtained.The main results are as follows:1.The phenotypic data of 10 drought tolerant traits in maize magic population showed continuous and normal distribution.The variation coefficient of different characters in the two environmental were larger,ranging from 7.10% to 93.84%.The coefficient of variation at silking stage was the smallest and the yield variation line was the largest.This shows that there is a large genetic variation in this population,which is controlled by environmental factors.Except that there is no significant correlation between powdering stage and 100 grain weight,there is a very significant or significant positive and negative correlation among drought tolerant traits.The correlation coefficient of the same type of drought tolerant traits is large,while that of different types is small.The minimum correlation coefficient is-0.35 and the maximum is 0.97.Through the analysis of variance,it was found that there were significant differences in drought tolerance traits under different treatments,which showed that there were abundant genetic variation in the population.2.The genotype analysis of maize MAGIC population was carried out by 48 K SNP chip,and159008 SNP loci were obtained,and then the genetic structure and kinship relationship analysis of maize MAGIC population were analyzed,and the results showed that the principal components and cluster analysis were consistent,and it was found that the population structure of the group was well controlled and there was no obvious population structure.The kinship results showed that the correlation coefficient between the strains in this group was low and the genetic difference was large.The genetic diversity of maize magic population was analyzed by 11661 SNP loci.The genetic diversity coefficient was 0.095 ～ 0.686,and the average value was 0.338;The polymorphism information content ranged from 0.091 to 0.631,with an average value of 0.273,indicating that the population was rich in genetic diversity.3.In this experiment,986 maize magic population materials were planted in the field,and the phenotypic data and population genotypes of 10 drought tolerance traits were obtained for genome-wide association analysis.A total of 256 significant SNP loci related to drought tolerance traits were detected,which were distributed on 10 chromosomes of maize.There were 117 associations in the loose pollen stage,92 associations in the silking stage,12 associations in the interval between male and female flowers,4 associations in chlorophyll,2 associations in plant height,9 associations in panicle height,7 associations in the number of effective panicles,1Association in the number of grains per row per panicle,3 associations in 100 grain weight and 9significant SNP loci in yield.The study of this paper is of great significance to deeply reveal the variation law of genetic diversity of maize germplasm resources and explore excellent germplasm or candidate genes related to drought tolerance traits. |
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