Validation of the Ceres-Wheat for Prediction of Wheat Varieties in Irrigation and Terminal Drought Stress

Problem statement: Crop growth models have many potential uses for crop managements. Approach: In order to evaluation of CERES-Wheat model on five varieties of winter wheat in Karaj weather condition in Full Irrigation (FI) and Stop Irrigation (SI) after flowering until final growth stage an experiment conducted in shape of split plot in based on randomize complete block design with four replicate in research field Islamic Azad university of Karaj branch in 2009-2010. Two irrigation levels located in main plot and cultivars as sub plot. In this study simulation of some traits such as Grain Yield (GY), Biomass (B) and Leaf Area Index (LAI) was evaluated by use of CERES-Wheat model. Results: According to results, model was successful in simulation of traits whole under two irrigation treatments. Rate of coefficient of correlation (R²) was low in regression curve of measured versus simulated for traits of LAI. Model simulated GY with high vigor for both irrigation conditions. Variation dimension of R² in FI and SI obtained 0.8089-0.8097 and 0.8087-0.9504, respectively. Variation dimension of Wilmot coefficient (d) FI and SI was 0.65-0.74 and 0.58-0.74, respectively. Simulation precise in SI was lower than FI. We could after evaluation and calibration model by means of experimental replication and reduce of Root Mean Square Error (RMSE) as a result used for research objective management programming in Karaj area. Conclusion: The results of CERES-Wheat model assessment in this research indicated that this model in full irrigation and discontinuing the irrigation after flowering stage have appropriate and good accurate, simulation of seed yield and biomass but has simulated the leaf area index well only in full irrigation conditions.