Development of climate-smart sorghum ideotype for climate resilience in Ethiopia

Developing climate-smart cultivars could be one climate change adaptation strategy for developing countries. The recent CSM-CERES-Sorghum model has the potential to develop a virtual cultivar that has unique traits to overcome the negative impacts of climate change. The goal of this study was to identify the possible advantage of developing sorghum ideotype in Ethiopia to minimize at least or capitalize at most the impacts of climate change in terms of sorghum productivity under future climate change. Projected climate change of four Global Circulation Models (GCM) (i.e., GFDL-ESM4, MPI-ESM1–2-HR, MRI-ESM2–0, and UKESM1–0-LL) from Coupled Model Inter-comparison Project phase 6 (CMIP6) were used to analyze the possible future climate change for our target environment. Rainfall, maximum temperature, minimum temperature, and solar radiation were spatially downscaled using the statistic downscaling method called bias correction/constructed analogues with quantile mapping reordering (BCCAQ) using an r-package called "Climdown" for two shared socio-economic pathways (SSP245 and SSP585) and two future periods of 2065 s (2051–2080) and 2035 s (2021–2050). The calibrated CSM-CERES-Sorghum model was applied to evaluate the performance of 4096 virtual sorghum cultivars relative to the reference cultivar Teshale and then identified the best-performing virtual cultivar traits that could be adapted to the projected climate change. Our results indicated that without applying the climate-smart cultivars in the future, the impacts of climate change could affect sorghum production by decreasing the mean national sorghum production under GFDL-ESM4 by 0.06–0.1 t/ha under SSP245 and 0.1–0.81 under SSP585. However, changing the reference cultivar with the climate-smart ideotypes can reverse the impact and increase the national mean sorghum production by 1 t/ha. The candidate ideotypes have the potential to increase sorghum grain yield under projected climate change by increasing the vegetative period (P1), reproductive periods (P3 and P4), grain filling (P5), relative leaf size (G1) and partition assimilation to head (G2). Our findings have implications for sorghum breeders in Ethiopia, who can use the identified traits to develop cultivars that can withstand heat stress and result in better yield under projected climate. This is important for ensuring food security in the face of a changing climate.