Research from the University of Lleida shows wheat is more sensitive to heat before flowering, though early exposure may provide a protective 'priming' effect against later heat waves.
Key facts
- •Wheat grain yield is more sensitive to heat waves occurring before flowering than after.
- •Early heat waves reduce the number of grains, while later heat waves reduce grain weight.
- •Plants exposed to early heat waves demonstrate a 'priming' effect that helps them withstand later heat stress.
- •The study was conducted by researchers at the University of Lleida using two modern wheat varieties.
- •Findings suggest that protecting crops during the flowering stage is critical for maintaining yields.
A study published in the Journal of Experimental Botany indicates that wheat crops suffer greater grain yield losses from heat waves occurring before the flowering stage than those occurring afterward. Researchers from the University of Lleida in Spain found that while early heat exposure reduces grain numbers, it can also prime the plants to better withstand subsequent heat stress during the reproductive phase.
Impact of Heat Wave Timing
The study, which conducted field experiments over two growing seasons, found that the timing of heat waves significantly alters crop damage. Heat waves occurring before flowering primarily reduce the total number of grains produced, whereas heat waves occurring after flowering tend to reduce the weight of individual grains. Researchers used transparent tents to simulate heat waves, measuring heat load based on accumulated temperatures above 32 °C.
The Priming Effect
The research identified a 'priming' effect, a form of physiological memory where an initial heat stress triggers protective responses in the wheat. Plants exposed to an early heat wave showed reduced negative impacts from a second heat wave later in the season compared to plants that only experienced the later heat event. This antagonistic interaction between successive heat waves is the first evidence of its kind in field-grown crops.
Implications for Agriculture
These findings suggest that farmers and researchers should prioritize protecting wheat during the stages when grain number is determined, particularly around flowering. The study notes that these results may also apply to other temperate crops like barley, oats, and rye, though specific temperature thresholds will vary. The researchers emphasize that predictive models for crop yields must account for multiple heat wave events to accurately assess climate change risks.
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This article was independently rewritten by ManyPress editorial AI from reporting originally published by Phys.org.
