Genetic Variation in Wheat Endosperm Proteins: an Analysis by Two-dimensional Electrophoresis Using Intervarietal Chromosomal Substitution Lines

The major endosperm proteins in a range of genotypes of hexaploid wheat have been fractionated by two-dimensional electrophoresis. The genotypes included nine varieties and forty four intervarietal substitution lines in which chromosomes 1A, 1B, 1D, 6A, 6B or 6D from eight of the varieties have been introduced one at a time into a common genetic background. The appearance of different protein subunits was often correlated with a chromosome substitution. This showed that many of the genes for the high molecular weight protein subunits (molecular weight range 55,000 to 140,000 determined by SDS polyacrylamide gel electrophoresis) are specified by chromosomes 1A, 1B and 1D while many of the lower molecular weight subunits (molecular weight range 30,000 to 45,000) are specified by chromosomes 6A, 6B and 6D. The different protein subunits correlated with chromosome substitution could not always be recognised in the varietal source of the substituted chromosome. The different subunits specified by homologous chromosomes in different wheat varieties may differ in isoelectric point and/or molecular weight.