Extreme heat during wheat flowering could become one of the most significant threats to global wheat production over the coming decades, according to new modelling research from Rothamsted Research.
While drought has historically been viewed as the dominant climate risk to wheat crops, the study suggests that short, intense periods of high temperature during the flowering stage may soon have a greater impact on yields.
Extreme Heat During Wheat Flowering Projected to Drive Yield Losses
Flowering is a critical developmental stage for wheat. It is the period when grain is set, directly influencing final yield. Even a few days of severe heat or water stress at this point can reduce grain numbers and significantly cut harvest volumes.
Using advanced climate projections alongside the Sirius wheat simulation model, researchers estimated how short heatwaves and drought events during flowering could affect global wheat yields under future climate scenarios.
The findings indicate a shift in relative risk. Drought during flowering currently causes greater yield loss globally than heat stress. However, its overall impact is projected to decline slightly over time.
By contrast, losses linked to extreme heat during wheat flowering are expected to increase substantially. By 2050, global yield losses associated with heat stress at flowering could rise by around one-third. By 2090, those losses could increase by more than three-quarters.
Implications for Breeding and Farm Management
The research highlights the need to prioritise heat tolerance traits in wheat breeding programmes. While drought resilience remains important, the modelling suggests that tolerance to short bursts of high temperature during flowering will become increasingly critical.
Adjustments in sowing dates and crop management strategies may also reduce the likelihood of flowering coinciding with peak heat periods, particularly in regions expected to experience more frequent heatwaves.
With global demand for wheat continuing to grow, maintaining stable yields under more volatile climate conditions is central to long-term food security. Identifying the stages at which crops are most vulnerable allows researchers, breeders and farmers to respond proactively.
The study underscores that preparing for heat stress — not solely drought — will be essential in building resilient wheat production systems for the decades ahead.
