Developing spring wheat ideotypes for India using a regional crop model

The adaptation of food production to climate change requires knowledge of the limitations and opportunities associated with changing climates across the globe, and the manner in which this varies for different crops. This information is essential to identify the genotypic properties that are needed to maintain high yields under climate change. The development of successful adaptation options is contingent upon a degree of accuracy in the climate change projections and in the simulation of the response of crops to climate. This paper presents an ensemble of crop yield that is used to determine climatic ideotypes for spring wheat in India for the period 2020 to 2100. These ideotypes have genotypic properties that result in non-negative yield changes across a range of future projections. The study uses the Hadley Centre QUMP (Quantifying Uncertainty in Model Prediction) climate ensemble together with perturbed parameter simulations using a regional scale crop model (GLAM, the general large-area model for annual crops, Challinor et al. 2004, Agriculture and Forest Meteorology, Vol. 124, pages 99-120). The period 1966 to 1988 was used for the calibration and evaluation of the crop model. A systematic assessment of parameter sets that are consistent with observations was performed to determine parameter values. The simulated yields capture well the North-South pattern of the observed spring wheat yield in India. Projections of crop yield were developed for the period 2020 to 2100. The resulting simulations are used to determine the magnitude and spatial extent of the impact of abiotic stresses on wheat. Since the crop-climate ensemble varies both climate and crop response to climate within appropriate uncertainty ranges, the simulations can be used to identify those biophysical processes that robustly dominate across a range of climates. Crop model parameters are adjusted to represent genotypic adaptation to climatic stress and to propose crop ideotypes for spring wheat in India for the period 2020 to 2100. Conclusions are drawn regarding: (i) the potential for genotypic adapation of spring wheat production in India and (ii) the potential of the tools presented to form part of a generalized methodology for other regions and crops.