LAUSR

Abstract Grain protein concentration (GPC), lysine, and essential amino acid (EAA) are key components of the nutritional quality of wheat. Quantitative analysis and numerical simulation of wheat nutritional quality based on the new findings in this study were used to extend the functionality of the CERES-Wheat model. The main assumptions in this model are as follows. (1) The minimum value of nitrogen stress and water stress, had a significant linear correlation with nitrogen-to-protein conversion factor (Fp). (2) An alteration in GPC, whether its cause is genetic or not, results in the same modifications in grain amino acid composition. (3) Amino acid compositions were precisely simulated by Fp and GPC. An appended module of nutritional quality was combined with a revised version of the CERES-Wheat model, enabling us to simulate wheat nutritional quality. The modified CERES-Wheat model could accurately simulate dry matter and nitrogen dynamics. The percent deviation differences between the simulated and observed average values of 16 treatments were all less than 10%. The RRMSE of GPC, EAA, and lysine were all less than 0.1. The nutritional quality module based on CERES-Wheat could accurately simulate GPC, lysine, and EAA. The simulated yield results were underestimated with severe nitrogen stress, while GPC, lysine, and EAA were overestimated with slight nitrogen stress. The nutritional quality module provides a simple mechanistic framework that explains environmental effects on GPC, EAA, and lysine.