Designing crops for adaptation to the drought and high-temperature risks anticipated in future climates

Climate risks pervade agriculture and generate major consequences on crop production. We do not know what the next season will be like, let alone the season 30 years hence. Yet farmers need to decide on genotype and management (GxM) combinations in advance of the season and in the face of this environment risk. Beyond that, breeders must target traits for future genotypes up to 10 years ahead of their release. Here we present the case for next generation design of GxMxE for crop adaptation in future climates. We focus on adaptation to drought and high-temperature shock in sorghum [Sorghum bicolor (L.) Moench] in Australia, but the concepts are generic. The considerable knowledge of climate, both past and future, gives us insight into climate variability and trends. We know that CO2 and temperature are increasing, and this influences drought and high-temperature risks for crops. We also have considerable knowledge of crop growth and development responses to CO2, drought, and high temperature that have been integrated into advanced crop simulation models. Here we explore by simulation the design of crops best suited to current and future environments. A yield-risk framework is used to identify adapted GxM combinations. The results in this case study indicate the urgent need for high-temperature tolerance to effects on seed set. Further, existing approaches to GxMfor effective use of water through the crop cycle will not be adequate to maintain productivity once global warming of similar to 2 degrees C is reached. Improvement in transpiration efficiency offered the avenue with best potential for advancing adaptation relevant to future climates.