Breeding for the future: How to adapt to potential impacts of future frost, drought and heat events on Australian wheat?

Abstract

While extreme climatic events (frost, heat and drought) can already severely limit wheat production, the expected future increase in extreme temperatures and rainfall variability will further challenge improvement in crop productivity. In addition, warming accelerates crop development, thus leading to potential mismatches between key sensitive growth stages and extreme climate events. Current combinations of management practices and genotypes might need to change in future environments to maximise utilisatino of seasonal resources (e.g. radiation, CO2, and nutrients) and to minimize stress risks. We analysed the patterns of frost, drought and heat events over the last decades across the Australian wheatbelt (Zheng et al 2012; Chenu et al 2013) and simulated crop development and drought patterns for future scenarios in 2030 and 2050 (high and low CO2 emission, dry and wet precipitation scenarios). Substantial changes in temporal and spatial distributions of frost, heat and drought events are expected for future climate scenarios. Given the expected reduction in crop-cycle duration and thus in the available time for the crop to acquire sufficient resources to set and fill grains, we also considered whether the Australian germplasm pool of wheat has sufficient genetic variabilities to maintain the growing season at the current duration. Daily mean temperature and occurrence of extreme climates (temperature and drought) have already increased in latest years in Australia (Murphy and Timbal 2008). It is urgent to consider adaptable varieties to the future as it will take 5 to 15 years to breed new wheat varieties (Chapman et al 2012).