Simulating Genotype x Environment x Management Interactions for Wheat Using Apsim: Model Evaluation and Application.

Rainfed farming systems in Pakistan are suffering from low productivity. Rainfall and temperature variability, exacerbated by climate change have caused significant crop losses. Implemented in the framework of Agricultural Production Systems Simulator (APSIM), the current study evaluated the impact of long term climate change on yield of wheat at three locations of Pothwar. Specifically, APSIM was employed to assess the impact of Genotype x Environment x Management interactions (G x E x M) to manage the productivity of select wheat genotypes recommended for the region. Model simulated yield under different scenarios were evaluated against actual data. The APSIM- G x E x M modules displayed good accuracy of model. The validation skill score r2 throughout exceeded 0.95 (RMSE: 4.41 days) for phenological development, 0.87 (RMSE: 1824.47 Kg ha-1) for drymatter and 0.85 (RMSE: 445.02 Kg ha-1) for grain yield. The results revealed the significance of phenology for accurate estimation of the duration of growing season and crop yield under changing climate, when used within the dynamic cropping systems model. Results highlight the role of simulation models as complementary tool to field experiments, to monitor and quantify G x E x M interactions and that of APSIM, in particular, as decision support tool to design innovative and sustainable farming systems under wide range of climatic conditions.