Modeling the effects of extreme high-temperature stress at anthesis and grain filling on grain protein in winter wheat

Extreme high-temperature stress (HTS) associated with climate change poses potential threats to wheat grain yield and quality. Wheat grain protein concentration (GPC) is a determinant of wheat quality for human nutrition and is often neglected in attempts to assess climate change impacts on wheat production. Crop models are useful tools for quantification of temperature impacts on grain yield and quality. Current crop models either cannot simulate or can simulate only partially the effects of HTS on crop N dynamics and grain N accumulation. There is a paucity of observational data on crop N and grain quality collected under systematic HTS scenarios to develop algorithms for model improvement as well as evaluate crop models. Two-year phytotron experiments were conducted with two wheat cultivars under HTS at anthesis, grain filling, and both stages. HTS significantly reduced total above-ground N and increased the rate of grain N accumulation, while total above-ground N and the rate of grain N accumulation were more sensitive to HTS at anthesis than at grain filling. The observed relationships between total above-ground N, rate of grain N accumulation, and HTS were quantified and incorporated into the WheatGrow model. The new HTS routines improved simulation of the dynamics of total above-ground N, grain N accumulation, and GPC by the model. The improved model provided better estimates of total above-ground N, grain N accumulation, and GPC under HTS (the normalized root mean square error was reduced by 40%, 85%, and 80%, respectively) than the original WheatGrow model. The improvements in the model enhance its applicability to the assessment of climate change effects on wheat grain quality by reducing the uncertainties of simulating N dynamics and grain quality under HTS. (C) 2021 Crop Science Society of China and Institute of Crop Science, CAAS. Production and hosting by Elsevier B.V. on behalf of KeAi Communications Co., Ltd.

Automated summary

This study investigated the impact of extreme high-temperature stress on wheat grain yield and quality, focusing on grain protein concentration as a key factor. The research found that high-temperature stress significantly reduced total above-ground nitrogen and accelerated grain nitrogen accumulation, with more sensitivity at anthesis compared to grain filling. The study also enhanced a crop model to better simulate nitrogen dynamics and grain quality under high-temperature stress, reducing uncertainties in assessing climate change effects on wheat grain quality.