Genetic Analysis Of Grain Drying Characteristic After Physiological Maturity And Relative Traits In Maize(Zea Mays L.)

The grain harvesting directly by machine is important for the development of Chinese corn production.However,it is always influenced by date of physiological maturity,grain drying rate after physiological maturity and grain moisture content at harvest.A set of 269 maize main inbred lines was used to investigate traits related to maize grain drying characteristics after physiological maturity in different environments.In connection with the whole genome-wide genotype data,the diversity of phenotype and the population structure were analyzed.Genome-wide association analysis was used to detect SNPs relate to grain drying characteristics and other traits.The relationships of different traits were clarified.Date of physiological maturity was significantly and negatively related to grain drying rate after physiological maturity.The grain moisture content at harvest was significantly and positively related to grain drying rate after physiological maturity.The result for heritability claimed that date of silking period,ear height,plant height and ear height/plant height performance a highly heritability,date of physiological maturity,grain drying rate after physiological maturity and grain moisture content at harvest showed moderate heritability,but the heritability of bract drying rate was low.The Structure analysis result showed that five groups could be classified in the accessions,five subgroups corresponding to different heterotic groups,that is TSPT,Reid,Lancaster,Ludahonggu and P.Accounting for 13.38% for TSPT,24.91% for Reid,15.24% for Lancaster,12.27% for Ludahonggu and 23.42% for P in total.Some other lines was defined as a mixed group,the ratio in total was 10.78%.Compared the differences of different heterotic group,the date of maturity period of P group was longer than other groups,and the grain drying rate after physiological maturity was slowly while grain moisture content at harvest higher than other groups,Reid and Lancaster groups showed a rapid grain drying rate after physiological maturity and the grain moisture content at harvest of them were low.Several SNPs relate to date of physiological maturity;grain drying characteristics and other traits were found.106 SNPs associated with date of physiological maturity were found,52 SNPs associated with grain drying rate after physiological maturity were found and 19 SNPs associated with grain moisture content at harvest were found.Checked the annotations of SNPs,two genes related to date of maturity period were found,one is coding the protein which control the chemical reactions and pathways resulting in the formation of cutin,a waxy substance in plants,the other coding the protein that control the developmental process in which the size or shape of a cell is generated and organized,but the function of these two genes should be verified in the future.