Grain quality variations from year to year among the Chinese genotypes

Under the random effect of year, the correct evaluation of varieties is the basis for the producing of high-quality wheat. In this study, 11 winter wheat varieties mainly cultivated in the North Yellow and Huai Valley of China were grown from 2011 to 2014 to investigate the effects of genotype, year, and their interaction on 15 major bread-making quality traits as well as the relationships between quality parameters, reliability, and suitability of the genotypes. We found that protein content, wet gluten content, sedimentation volume, test weight, and falling number were mostly influenced by the year. Annual variations in the relationships between quality traits differed considerably. Correlation coefficients between gluten index and both maximum resistance and dough stability ( r = 0.68 to 0.88) were significant over the three growing seasons. A high intra-class correlation coefficient for gluten index (0.74) was observed. Gluten index is a reliable early-generation predictor of gluten strength. Bidimensional clustering analysis and heatmap are useful for suitability analysis of high-quality wheat. Safety-first indices can be useful to plant breeders for reliability analyses of high-quality genotypes, and only one genotype was screened out. The considerable effects of year were demonstrated, suggesting that the reliability of quality genotypes should be improved in the North Yellow and Huai Valley of China.