High Mr Glutenin Subunits of Indian Wheat Cultivars: Association of Subunits 5 + 10 with the 1BL/1RS Wheat-Rye Translocation

Abstract

The seed proteins of 110 commercially-released Indian wheat cultivars were fractionated using sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE) to determine their high Mr glutenin subunit compositions. Amongst the cultivars, three alleles were indentified for the Glu-A1 locus (subunits 1, 2* and the null phenotype), eight alleles for the Glu-B1 locus (7, 7 + 8, 7 + 9, 6 + 8, 20, 13 + 16, 17 + 18 and a new allele) and two for the Glu-D1 locus (2 + 12 and 5 + 10). Nine of the cultivars were heterogeneous and possessed two or more 'biotypes' with respect to high Mr subunits. The cultivars were also analysed for the presence of the 1BL/1RS wheat-rye translocation by SDS-PAGE of unreduced prolamins and hybridisation of DNA dot blots with a rye-telomere-specific repetitive DNA probe, pAW-161. Both methods revealed that the majority of newly-released Indian wheat cultivars carry this translocation, thus confirming the agronomic superiority of these lines. While most of the normal wheat cultivars possessed high Mr subunits 2 + 12, 14 of the 18 translocation cultivars had the allelic subunits 5 + 10, even though no selection was made for these subunits during the breeding process. This suggests that the subunits 5 + 10 may play a compensating role for the loss of dough strength associated with the 1BL/1RS translocation.