Drip irrigation affects dough processing quality by regulating synthesis of glutenin macropolymers in wheat grain

Field experiments on the Huang-Huai-Hai Plain evaluated drip irrigation's effect on two high-gluten wheat varieties (ZM886, ZM998) under five treatments: rain-fed (W0) and drip irrigation (300-W1, 450-W2, 600-W3, 750-W4 m³ ha⁻¹). Compared to W0 (7855.87 kg ha⁻¹), irrigation increased grain yield by 5.37–12.45 % (ZM886) and 7.01–17.19 % (ZM998).Dough stability time decreased in ZM886 (4.00–24.25 %) across all irrigation levels versus W0. For ZM998, it declined under W3 (4.98 %) and W4 (14.29 %) but increased under W1 (7.00 %) and W2 (3.36 %). Dough tensile resistance increased in ZM886 under W1 (5.25 %) but decreased under W2-W4 (2.37–36.93 %); ZM998 saw increases under W1 (19.89 %) and W2 (4.18 %) but decreases under W3 (15.01 %) and W4 (21.99 %). Soluble glutenin protein (SGP) to glutenin macropolymer (GMP) conversion occurred at 26 days post-anthesis under W0; higher drip irrigation delayed high-molecular-weight glutenin subunit (HMW-GS) detection. Irrigation generally reduced GMP, SGP, disulfide bonds (-S-S-), free thiol groups (free -SH), and HMW-GS, with the largest reductions under W4 (e.g., GMP: −34.00 % ZM886, −39.38 % ZM998). Conversely, moderate irrigation (W1) increased free -SH (3.25 % ZM886, 4.53 % ZM998) and -S-S- (8.54 % ZM886, 9.33 % ZM998), and slightly increased GMP in ZM886 (2.23 %) and SGP in ZM998 (0.57 %).Moderate irrigation (W1, 300 m³ ha⁻¹, WUE 6.10–7.55 kg ha⁻¹ mm⁻¹) optimized dough stability time and tensile resistance by influencing SGP depolymerization, HMW-GS content, and GMP modulation, achieving the best balance between dough quality and yield for water-efficient cultivation. • The presence of glutenin macropolymers was first detected in grains 28 days after anthesis. • A single drip irrigation < 450 m³ ha- 1 improves wheat quality by increasing HMW-GS and GMP content. • HMW-GS had a greater effect on wheat processing quality than GMP.