Effects of CO2 and illumination on wheat grain yields based on APSIM model

In order to explore the effects of illumination intensity and CO2 concentration on wheat (Triticum aestivum) grain yield, the grain yield under different illumination intensities and CO2 concentrations was simulated by validated Agricultural Production System Simulator Model（APSIM） and cooperation factors were analysised by multiple regressions. The results showed that the grain yield rapidly decreased with the increase of illumination intensity under the same CO2 condition which had maximum grain yield losses of 17.16% and the average grain yield losses of 9.40% with the light intensity increased by 0.5 MJm-2. The grain yield increased with the increase of CO2 condition under the same illumination intensity which had maximum grain yield losses of 22.08% and the average grain yield losses of 11.27% with the CO2 concentration increased by 100 molmol-1. There was negative interaction between light intensity and CO2 concentration which suggested the local environment was suitable for wheat growth.