Though model results are more sensitive to stress during reproductive stages as compared to vegetative stages, simulations could use improvement to reflect heat stress at both stages. For better simulation of crop responses under increasing temperature and CO 2, is also important for crop modelers to improve models for better use in changing temperature and heat stress. Reducing the uncertainty surrounding the quantification of climate change impacts in models is a major concern of crop modelers. reported 6% reduction of global wheat yield with 1☌ increase of temperature during the most comprehensive analysis to date using crop simulation models.Ĭrop models have a higher uncertainty in their simulation at elevated temperature due to their incorporated structures and functions. Increasing temperature affects wheat growth and development, resulting in smaller grains at 25–35☌ due to shorter grain filling duration and reduced photosynthetic efficiencies at temperatures above 30☌. For example, an increase in temperature at flowering stage may cause pollen sterility in crops. Temperature and heat fluctuation negatively affects the morphological, physiological and yield contributing factors of crops. Hot and dry region are expected to be particularly vulnerable to climate change associated yield losses associated with increased temperature. Overall, there is a need of improvement in function of models to response high temperature. APSIM-Wheat only poorly simulated days to maturity of very and extremely late sown wheat compared to other models. Improvement in simulation of maximum leaf area index of wheat for all models is needed. The poor accuracy of simulations of yield for extreme planting dates point to the need to improve the accuracy of model simulations at the high end of the growing temperature range, especially given the expected future increases in growing season temperature. Overall, the four models described performance of early, optimum and late sown wheat well, but poorly described yields of very late planting dates with associated high temperatures during grain filling. The CERES-Wheat, Nwheat, CROPSIM-Wheat and APSIM-Wheat model were calibrated against the least-stressed treatment for each wheat cultivar. Apsim model sensitivity to phyllochron series#The wide series of sowing dates was a unique opportunity to grow the wheat in an environment which temperatures varies from -0.1☌ to 43☌. Wheat growing season temperature ranged from -0.1☌ to 43☌. Robustness of four wheat simulation model were tested with 2-year field experiments of three cultivars across a wide range of sowing dates in two different climatic regions: Faisalabad (semi-arid) and Layyah (arid), in Punjab-Pakistan.
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