Karine Chenu, Florianne Oudin
The University of Queensland, Queensland Alliance for Agriculture and Food Innovation (QAAFI), Toowoomba, QLD, Australia
In recent decades, rising temperatures have increasingly affected wheat crops in major producing regions around the world. Climate models predict further increases in mean temperature and in the frequency of temperature extremes for the near to mid-future.
The impact of heat on wheat at different periods of the crop cycle was studied in two experiments conducted with finely controlled temperatures in a glasshouse. While heat shocks affected the main stem and primary tillers of a plant differently, a common response to heat was found for all stems (irrespective of their rank), when considering the timing of the stress relative to stem anthesis. The greatest impact on grain number was observed for stress applied ~10 days before stem anthesis. The impact of pre-anthesis stress on grain set were slightly compensated by an increase in individual grain weight. Overall, grain yield was substantially affected for early pre-flowering stress and early-to-mid post-flowering stress. The results of this study have been used to improve estimations of heat impact in crop modelling and thus improve the accuracy of crop simulations for future climate scenarios.