Evaluation of allelic variation for HMW glutenin subunits through SDS-PAGE in diverse bread wheats
By: Hidayat Ullah, Habib Ahmad, Armghan Shahzad, Ahmad Ali, Ghulam Muhammad Ali
Key Words: Allelic diversity, HMW-GS, SDS-PAGE.
Int. J. Biosci. 9(1), 203-214, July 2016.
High-molecular weight glutenin subunits (HMW-GS) play a key role in determining end-use quality of common wheat by estimating the viscoelastic properties of dough and flour. We analyzed the HMW-GS subunit composition and variation at the Glu-1 locus in a core collection of 7 diverse groups of wheat genotypes. Fourteen different wheat standards were utilized for allocating allelic designations to HMW glutenin subunit mobility by SDS-PAGE. Scoring of high HMW-GS subunits in the evaluated genotypes was based on standard electrophoresis patterns using the Payne and Lawrence scoring system. A total of eighteen alleles among the germplasm at Glu-1 loci were detected, 3 at the Glu-A1locus, 11 at the Glu-B1and 4 at the Glu-D1 locus. Thirty four different combinations of HMW-GS alleles were found and higher variations occurred at the Glu-B1 locus compared to Glu-A1 and Glu-D1 loci with relatively high diversity (H=0.83). The distribution of allelic patterns varied among these seven groups and high genetic polymorphism in HMW-GS composition was observed. Together, 45.65% of the alleles detected were rare alleles. Glu-A1a (1Ax1), Glu-A1c (null), Glu-B1a (1Bx7), Glu-B1h (1Bx17 + 1By18), and Glu-D1a (1Dx2 + 1Dy12) alleles were found most frequently at Glu-D1 locus, the frequency of the superior alleles 1Dx5+1Dy10 (50.00%) was observed in maximum genotypes than the inferior allele 1Dx2+1Dy12 (40.83%). The high quality score for HMW glutenin subunits found in the studied genotypes are potential sources of desirable quality traits to be used in main wheat breeding programs for improving bread- baking quality.