The variations in winter wheat potential yields in the middle and lower reaches of the Yangtze River under the RCP scenarios

The purpose of this study was to evaluate the effects of climate change on the potential yield of winter wheat in the middle-lower Yangtze area. Based on the BCC-CSM1-1 (Beijing Climate Center Climate System Model version 1-1) climate system model proposed by the United Nations Intergovernmental Panel on Climate Change( IPCC) AR5, and historical daily meteorological elements were obtained under different RCP scenarios (baseline, RCP2.6, RCP4.5, and RCP8.5). In our study,which used the DSSAT-GLUE module, the phenotype and yield of winter wheat for the historical period (2001-2009) was used to optimize parameters and test the model performance. The performance of the parameters and model was evaluated by the normalized root mean squared error (NRMSE) and the consistency index (D). Then the wheat yield over the next 30 years was predicted by DSSAT, and its change trends were analyzed using meteorological elements recorded between 1961 and 1990 and future predictions (2021-2050). After parameter optimization, the NRMSE for flowering duration and maturity duration ranged from 0.83% to 2.98%, and the NRMSE for yield was below 7%. Climate change will have negative effects on future agricultural production and food security. The results showed that under the RCP2.6 scenario, accumulative temperature (>10°C) decreased significantly compared to the baseline climatic condition, but increased in the other two scenarios. The precipitation fluctuation was relatively large with obvious regional differences and an insignificant change rate. The total solar radiation in the three RCP scenarios was lower than the baseline, whereas the rate decreased as the number of years increased. Simulated accumulative temperature (> 10°C), precipitation, and solar total radiation during the growing period 2021-2050 compared to the baseline climatic condition had different change tendencies. When only the climate factors were taken into account (without considering CO2 concentration effect, variety substitution, soil change, and management optimization), the growth period and yield of winter wheat had different change tendencies. In the RCP2.6 scenario, except for Kunshan, the flowering and maturing stages for winter wheat were delayed (RCP8.5>RCP4.5), and the days from flowering to maturity decreased. In general, there was a significant difference in regional trends for potential yield: Kunshan and Yingshan declined more than Chuzhou and Zhongxiang (3% -59%); yield reduction in Kunshan