Identification of Glu-A3 and Glu-B3 of Low-Molecular-Weight Glutenin in Shanxi Wheat and Its Effect on Quality

Low molecular weight gluten subunits (LMW-GS) are crucial components in determining the end-use quality of common wheat. Elucidating the diversity and impact on flour quality of LMW-GS is essential for genetic improvement in wheat.

A collection of 421 Shanxi wheat accessions was utilized to identify allelic variations in the Glu-A3 and Glu-B3 using 18 specific markers. The polymorphism, genetic diversity, and cluster analysis of these alleles in Shanxi wheat was then conducted. Additionally, the effects of these alleles on the physicochemical quality, farinograph and extensograph properties, as well as dough viscosity characteristics of flour were investigated.

The allelic variations in the Glu-A3, by frequency, are Glu-A3b, Glu-A3c, Glu-A3g, Glu-A3d, Glu-A3f, Glu-A3a, and Glu-A3e. At the Glu-B3, the identified allelic variations are Glu-B3g, Glu-B3a, Glu-B3d, Glu-B3i, Glu-B3b, Glu-B3h, Glu-B3e, Glu-B3c, and Glu-B3f. The genetic distance range for Shanxi wheat is 0.000 to 0.667, with a mean value of 0.253. It was observed that cultivars exhibited a greater genetic distance than landraces. Geographical distribution and irrigation/dryland types also influenced the genetic diversity of LMW-GS. Correlation analysis revealed that six LMW-GS allelic variations significantly correlated with five physicochemical quality traits. Glu-A3b, Glu-A3d, and Glu-B3i had negative effects on protein content, while Glu-A3b and Glu-B3i had positive effects on starch content. Glu-A3d and Glu-B3i showed positive effects on fiber content, and Glu-B3i increased the whiteness value of flour by 2.10%. Fifteen LMW-GS allelic variations were identified as significantly correlated with 12 processing quality traits, with Glu-A3e and Glu-B3d increasing extensibility by 36.71 and 19.91 mm, respectively. Glu-A3a, Glu-B3b, and Glu-B3e had positive effects on improving development time, stability time, stretch area, extension resistance, stretch ratio, and farinograph quality. Five LMW-GS subunits were significantly correlated with dough viscosity characteristics, with Glu-A3a increasing peak viscosity by 183.19 cp and the pad abort value by 67.79 cp.

LMW-GS alleles in Shanxi wheat exhibited high polymorphism. Geographical distribution and accession types affected the genetic diversity at the Glu-A3 and Glu-B3 loci. Six, fifteen, and five LMW-GS allelic variations were identified as showing significant correlations with flour physicochemical, processing quality, and dough viscosity traits, respectively.