COMPARISON OF THE B-SUBUNITS AND D-SUBUNITS OF GLUTENIN ENCODED AT THE GLU-D3 LOCUS IN 2 BIOTYPES OF THE COMMON WHEAT CULTIVAR NEWTON WITH DIFFERENT TECHNOLOGICAL CHARACTERISTICS

The common wheat cultivar Newton occurs as two biotypes with different electrophoretic patterns of the Gli-D1-encoded ?-gliadins, which resemble the analogous patterns found in the cultivars Chinese Spring and Cheyenne. The ?-, ?- and ?-gliadin and high molecular weight glutenin subunit patterns are identical, however. The two biotypes, which have different technological properties, have been used to study the B and D groups of low molecular weight glutenin subunits encoded at the Glu-D3 locus, which is tightly linked to Gli-D1, in order to detect possible relations between these subunits and breadmaking properties. Whereas Newton (Chinese Spring type) possessed D subunits of glutenin, Newton (Cheyenne type) had only ?-gliadins in the corresponding field of the two-dimensional electrophoresis gel. D subunits appear to originate from mutated ?-gliadin coding genes. A comparable situation was also found in the cultivars Chinese Spring and Cheyenne. Analysis of the B group of low molecular weight glutenin subunits indicated that each biotype possessed one specific component that differed between the two. The 1D-encoded basic low molecular weight glutenin subunits of the cultivars Chinese Spring and Cheyenne were similarly differentiated. The role of these different low molecular weight subunits of glutenin in the two Newton biotypes in determining breadmaking quality characteristics is now under investigation.