Grain hardness variation of wheat grown in Chinese winter wheat regions.

65 and 43 cultivars separately sown at 11 locations of North Winter Wheat Regions and 4 locations of the South Winter Wheat Regions in 2001 and 2002 growing season were used to investigate the grain hardness variance in different planting sites.Results showed that hard wheat frequency in North Winter Wheat Regions was higher than that in South Winter Wheat Regions,soft and mixed wheat frequency in the former was lower than that in the latter.Cultivars from North Winter Wheat Regions performed higher grain hardness than that from South Winter Wheat Regions.The hardness of Hard wheat varieties from North Winter Wheat Regions was higher than that from South Winter Wheat Regions,but soft and mixed wheat cultvars from both regions almost had the same hardness.Among total 108 cultivars,Xinong 8925-13 had the highest hardness,while WG6 had the lowest.47 hard wheat cultivars from North Winter Wheat regions had the smallest c.v.% in hardness among planting sites with only 7.5 %,while 22 soft cultivars from South Winter Wheat regions had largest c.v.% of 26.3 %.For variety and sites,the smallest c.v.% were 2.6 % and 26.7 % in Zhoumai 12 and Zhoukou,respectively,the largest c.v.% were 72.7 % and 49.7 % in Yang 97-65 and Baimahu,respectively.Results also indicated that effects of genotype on grain hardness were far greater than that of G×E interaction and environment.