Differential analysis and genome-wide association analysis of stomata density of maize inbred lines leaves at ear position

The stomata of maize leaves is closely related to photosynthesis and transpiration, and the genetic study of maize stomatal phenotypesis important for maize breeding. In this study, rapid scanning electron microscopy (RSEM) was used to obtain images of the abaxial stomata of 457 maize inbred lines with extensive genetic variation, and the trait of stomata density was obtained by counting. The results showed that stomata density was significantly correlated with ear leaf width. And analysis of variance found that there were significant differences (P value<0.05) in stomata density among different ear leaf width, 100-grain weight, kernel number per row, ear row number and kernel weight per corn. High yield-related lines had higher stomata density than those of low yield-related lines. Moreover, high yield-related leaf shape promotes high kernel weight per corn, and lines with medium stomata density promoted kernel weight per corn significantly. Finally, genome-wide association analysis was performed using a mixed linear model (MLM). It showed that eight SNPs significantly associated with stomata density were obtained, which could explain 35.507% of the phenotypic variation. Among these, four SNPs on chromosome 5 were tightly linked, mainly formatting two haplotypes: CTTA (0.636) and TCCG (0.330). Twelve genes with functional annotation were identified within 100 kb upstream and downstream of the eight SNPs. Of these, GRMZM2G068277 had been shown to be involved in plant mitotic processes and exhibited high expression at the leaf base. The results presented here will provide references for further cloning of functional genes related to stomata density.