Gene ZmCRK3 for regulating and controlling corn grain size and amino acid content as well as encoding protein, SNP (Single Nucleotide Polymorphism) site, functional marker and application of gene ZmCRK3

The invention discloses a corn size and amino acid content regulation gene ZmCRK3, and an encoding protein, an SNP site, a functional marker and application thereof, and aims to provide excellent haplotypes and germplasm resources with the excellent haplotypes for improvement of corn yield and quality. Based on a grain mutant of the ZmCRK3 gene, co-separation of the grain mutant and a grain mutation phenotype is determined through genotype identification and linkage analysis, ZmCRK3 mutation influences the size and the amino acid content of corn grains, and a primer, an amplification system and a PCR reaction program for detecting the mutation genotype of the grain mutant are provided; sNP influencing the grain size and the amino acid content is excavated through correlation analysis, the excellent haplotype of ZmCRK3 is determined through haplotype analysis, and germplasm resources with the excellent haplotype of ZmCRK3 are identified; by utilizing the gene and the molecular marker disclosed by the invention