Breeding for the future: How to adapt to frost, drought and heat impacts in 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 climate 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 utilisation 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 and 2015; Chenu et al 2013) and simulated crop development and drought patterns for future scenarios 2030-2070. The results highlighted substantial changes in temporal and spatial distributions of frost, heat and drought events for future climate scenarios. Given the expected reduction in crop-cycle duration and thus in the available time for the crop to acquire resources to set and fill grains, we also considered whether the Australian wheat-germplasm pool has sufficient genetic variability to maintain the duration of the growing season at its current level.

Daily mean temperature and the occurrence of extreme climates (temperature and drought) have already tended to increase in latest years in Australia (Murphy and Timbal 2008; Chenu et al 2013; Zheng et al 2015). As 5 to 15 years are required to breed new wheat varieties, it becomes urgent to consider adaptation of varieties to the future (Chapman et al 2012).