Abstract:

A simulation model for yield components and final yield in winter wheat (WYSM) was established based on the physiological and ecological characteristics of yield formation of winter wheat, which is as a submodel of whole wheat growth simulation model. The effects of low temperature, water stress from forming to grain filling stage and high temperature at late growing season on wheat grain number were integrated into the model. The grain filling stage was divided into three sub-stages and the maximum grain-filling rates for each sub-stage were introduced. The effects of temperature, water stress and N/C ratio of grains were considered to simulate actual kernel weight, the source and sink relation was also considered in the model to modify grain-filling rate. Finally the method of yield components was used to establish the final yield prediction model of winter wheat. The field experiment data for different years and different cultivars in Beijing and Henan Province of China were used to validate this model. The results showed that WYSM model well simulated the yield components and final yield of wheat. The grain number, grain weight, yield and grain filling process were predicted with an NRMSE of 4.2%–10.9%, and the average of absolute relative error (RE) of 2.9%–6.7%. The adjusted linear correlation coefficient (R²) between simulated and observed values is 0.88–0.99. The results indicate that the model has not only good mechanism in model building, but good simulation capability and applicability.

Key words: Winter wheat, Yield components, Grain number, Grain weight, Simulation model