Designing high-yielding maize ideotypes to adapt changing climate in the North China Plain

Global food production to meet growing demand is facing serious challenges from changing climate. Efficient adaptation is an important approach for mitigating the effects of changing climate on crop production and secure food supply in the future. Maize is a critically important source of food, feed and fuel, and is highly vulnerable to warming climate. In our study, using Agricultural Production Systems sIMulator (APSIM) model, we designed different features of maize ideotypes sown at various times to maximize the yield and water use efficiency (WUE) under future climate conditions in the North China Plain (NCP). The future climate projections were sourced from one Global Climate Model (GCM) from the Coupled Model Inter-comparison Project phase 6 (CMIP6) under a high emission scenario of future societal development pathway (SSP) 585. The selected GCM projected future mean maximum (minimum) temperature during maize growing season to increase by 1.9 degrees C and 3.7 degrees C (1.5 degrees C and 3.2 degrees C) in 2040s (2031-2060) and 2080s (2071-2100) respectively, compared to the baseline (1981-2010). The mean solar radiation during maize growing season increased by 3.9% and 6.5%, and total precipitation rose by 17.3% and 21% in 2040s and 2080s, respectively. Our simulated results indicated future maize yield without adaptation decreased slightly by 2.3% in 2040s and 2.4% in 2080s, but WUE significantly increased by 11.8% and 26.6% in 2040s and 2080s, respectively. We found that delayed sowing date was able to increase maize yield and WUE under the future climate conditions. When the ideotypic cultivar and optimum sowing date were adopted, simulated yield increased by 132% and 124% in 2040s and 2080s, respectively, and WUE rose by 85% and 117%, respectively. Our simulated results indicate maize ideotypes under future climate should have a longer reproductive growing period, faster potential grain filling rate, larger maximum grain numbers and larger radiation use efficiency. Maize ideotypes based on simulated results from APSIM models could provide breeders and/or plant scientists with a road map to choose the ideal target traits for increasing maize production and adapting future climate.