Variation in type and relative amounts of the high molecular weight glutenin subunits in dutch wheat varieties

The high molecular weight glutenin (HMWg) subunit genotypes and amounts of the individual subunits of 38 Dutch wheat varieties were determined. In winter wheat varieties, HMWg subunit alleles that, in general, have been shown to be related to a poor bread‐making quality predominated. In spring wheat varieties, ‘high‐quality’ alleles were most frequent. When examining the published HMWg subunit genotypes of British and German varieties a similar difference was found in HMWg subunit genotype between spring and winter wheats. Because bread‐making quality of spring wheat varieties is, in general, superior to that of winter wheats, probably also because of the lower protein content of the latter, the two groups should be taken separately when studying the relation between HMWg subunit genotype and bread‐making quality. There was a considerable variation in relative amounts of allelic HMWg subunits and of subunits encoded by different genes (at the same or homeologous loci). Between varieties with the same HMWg subunit genotype, relative amounts of identical subunits differed only slightly. Some of these differences may reflect differences in gene expression, but it is not known to what extent differences in genetic background or differences in gene promoter are involved. There were differences in relative amounts of HMWg subunits encoded by alleles at the Glu ‐ Bl locus. Here, an increase in relative amounts coincided with an increase in contribution to bread‐making quality of an allele.