Genome-wide association study of grain morphology in wheat

Grain morphology is an important agronomic trait since its strongly associated with thousand kernel weight, which is one of the main objectives for high-yield wheat breeding. The grain morphology-related traits were controlled by QTLs which were pyramided in wheat cultivars. To detect more genetic variants for grain morphology-related traits in improved varieties, a panel of 543 wheat accessions were phenotyped at three locations over 2 years with seven grain morphology-related traits: grain length (GL), grain width (GW), ratio of GL to GW, grain diameter, grain roundness, grain circumference, and grain surface area. Combined with 90 K Illumina iSelect single nucleotide polymorphism (SNP) array, a total of 47 significance SNPs on chromosomes 1A, 1B, 2A, 2B, 2D, 3A, 3B, 3D, 4B, 5B, 6A, 6B, 6D, and 7B were detected. An analysis of all loci identified 400 candidate genes, 22 of which included at least one significant SNP. The functional characterization of these candidate genes provided new insights into the genetic basis of wheat grain morphology.