Investigation on the Effects of Climate Change on the Growth and Yield of Different Maturity Winter Wheat Varieties in Northern China Based on the APSIM Model

This study aims to clarify the impacts of climate change on the growth, development and yield of winter wheat of different maturity, so as to provide a theoretical basis for the sustainable production of wheat under future climate change.

The data about growth of two winter wheat varieties of Liangxing 99 (late-maturing) and Zhongke 2011 (early-maturing), soil, and meteorology, which were observed under different temperatures and [CO₂] treatments in the open top chamber in 2017-2020, were used to calibrate and validate the APSIM (agricultural production systems simulator) model. Then the verified model was used to simulate winter wheat yield, yield composition and phenology dates under different future climate conditions (RCP 4.5 and RCP 8.5) with a baseline period of 1986-2005. And the impacts of climate change and extreme high temperature on the production potential of different maturity winter wheat varieties were analyzed.

The APSIM model was able to well simulate the phenology, yield and biomass under different air temperature and [CO₂] treatments since the simulated and measured values of R² were higher than 0.614 and the values of nRMSE were all lower than 10.6%. However, the simulation result of leaf area index (LAI) was relatively poor. For the long-term simulation results, under different climate conditions, the days from sowing to jointing were shorter than the baseline for two wheat varieties. The shortened days of early-maturing variety were smaller than those of late-maturing variety. There was no obvious change in the days from jointing to maturity between the two varieties. The yield and potential yield of the two wheat varieties were higher under the future RCP conditions than under the baseline period. The yield and potential yield were the highest under the RCP 8.5 condition in 2100s. The yield and potential yield of early-maturing variety were more remarkably increased than those of late-maturing variety. Compared with the baseline, the LAI values of the two wheat varieties increased in the early growth stage. Then, the LAI of the late-maturing variety decreased obviously in the late growth stage, while the LAI of the early-maturing variety had no obvious difference. The aboveground biomass of the two wheat varieties both increased, and the early-maturing variety increased more remarkably than the late-maturing variety. Under different RCP conditions, extreme high temperature had negative impacts on the yield and 1 000-grain weight of the two varieties of winter wheat. Extreme high temperature at flowering stage had the greatest impact on 1 000-grain weight. Compared with the normal years, the 1 000-grain weight and yield of late-maturing variety decreased obviously in extreme-high-temperature years under the RCP 8.5 condition in 2100s, while the grain number also decreased slightly. Under different RCP conditions, compared with the normal years, extreme high temperature obviously reduced the 1 000-grain weight of early-maturing variety but slightly increased the grain numbers. Thus, yield reduction of early-maturing wheat variety in extreme high temperature years was not obvious.

Early-maturing variety of winter wheat will be more adaptable to future climate change. Thus, breeding of wheat varieties to adapt to climate change is one of the effective measures to cope with future climate change.