Relationship between pre-harvest sprouting and functional markers associated with grain weight, TaSUS2-2B, TaGW2-6A, and TaCWI-A1, in Korean wheat cultivars

Pre-harvest sprouting (PHS) resistance, measured by germination index, and grain traits, including grain length, width, thickness, roundness, test weight, and 1000-kernel weight, were evaluated for four years in this study. Functional markers associated with grain weight, TaSus2-2B, TaGW2-6A, and TaCwi-A1, were also evaluated because grain weight is related to PHS resistance in Korean wheat cultivars. The objective of the study was to determine the relationships among PHS and grain traits, and functional markers to improve PHS resistance in Korean wheat breeding programs. Grain traits, test weight, 1000-kernel weight, and germination index were influenced significantly by genotype, year, and the interaction between year and genotype. Germination index values correlated positively with 1000-kernel weight (r = 0.568, P < 0.001) and grain traits, except grain roundness. White- grained wheat cultivars showed wider length, width, and thickness of grain and 1000-kernel weight than red-grained wheat cultivars. Wheat cultivars that carried TaSus2-2B with the Hap-L haplotype showed a higher germination index (0.61) than TaSus2-2B with the Hap-H haplotype (0.18). Wheats that carried the TaGW2-6A-G haplotype showed higher 1000-kernel weight (44.62 g) than the TaGW2-6A-A haplotype (39.75 g), although there was no significant difference in germination index between Korean wheat cultivars. Red-grained wheat cultivars that carried the TaCwi-A1a allele showed higher test weights than with the TaCwi-A1b allele and the white-grained wheats that carried the TaCwi-A1a allele exhibited wider length and thickness of grain and higher 1000-kernel weight than those with the TaCwi-A1b allele.