Abstract: High-molecular-weight glutenin subunits (HMW-GS) are key determinants of wheat processing quality. To evaluate the effects of different HMW-GS under a relatively consistent genetic background on the processing quality of wheat, ethyl methanesulfonate (EMS)-induced single-subunit deletion mutants of the strong-gluten wheat cultivar Zhoumai 36, including 1Ax1, 1Bx7, 1By8, 1Dx5, and 1Dy12 deletions, were obtained and analyzed for grain quality, farinograph characteristics, dynamic rheological properties, and gluten microstructure. All deletion mutants showed significant decreases in sedimentation value, dough development time, dough stability time, farinograph quality number, and gluten index. Compared with Zhoumai 36, dough stability time decreased by 57.70%–77.51%, and farinograph quality number decreased by 52.72%–71.30%. Flour water absorption increased significantly in the 1Ax1 deletion mutant, whereas test weight decreased significantly in the 1Bx7 and 1Dx5 deletion mutants. Wet and dry gluten contents increased significantly in the 1Dx5, 1Bx7, 1By8, and 1Dy12 deletion mutants. Principal component analysis (PCA) reduced 11 quality traits to two principal components, explaining 81.15% of the total variance. The comprehensive scores of the mutants were ranked as follows: 1By8 deletion > 1Dy12 deletion > 1Ax1 deletion > 1Dx5 deletion > 1Bx7 deletion. Frequency sweep measurements and scanning electron microscopy (SEM) observations showed that HMW-GS deletion reduced storage and loss moduli, increased tan δ, and altered gluten network structure. Overall, 1Dx5 and 1Bx7 deletions exerted greater effects on gluten network structure and dough strength. These mutants may serve as candidate resources for weak-gluten wheat, although their end-use processing quality requires further validation.

Key words: wheat; high-molecular-weight glutenin subunit deletions; processing quality; dynamic rheological properties; principal component analysis