Optimizing water-nitrogen management for enhanced nutritional quality and mineral biofortification in dry-land winter wheat cultivars on the loess Plateau, China.

Wheat grain nutritional quality directly influences human health. While appropriate water and nitrogen management significantly enhance wheat yield, their specific effects on grain quality remain insufficiently explored. We investigated the impact of varying water and nitrogen treatments on dryland wheat variety quality. To assess quality and mineral element content parameters, winter wheat cultivars underwent to two water regimes (sufficient and insufficient) combined with two nitrogen fertiliser levels (sufficient and insufficient). Results indicated that sufficient nitrogen fertilisation (N2) increased mineral element contents; albumin, globulin, glutenin, and wet gluten levels; starch swelling capacity; grain hardness; and favourable gelatinization characteristics. Under insufficient nitrogen application (N1), adequate irrigation (W2) also improved grain mineral element contents, amylose levels, protein content, and the amylose/amylopectin ratio. W2N2 treatment, compared to W1N1, enhanced grain phosphorus, potassium, and sulfur levels, and the amylose/amylopectin ratio. Correlation analysis revealed strong positive associations among nitrogen, sulfur, manganese, copper, amylose, wet gluten content, and gelatinization temperature. Interestingly, modern cultivars exhibited optimal grain quality under the W1N1 treatment, suggesting their quality is maintained even in low-input systems. However, overall dryland wheat quality did not improve with yield during varietal replacement. Therefore, variety selection based on environmental constraints and management practices is crucial for optimizing both grain quality and resource utilization.