The freezing resistance of winter wheat is under increasing pressure due to climate change, with extreme low-temperature events becoming more frequent. Researchers have recently tackled this pressing issue, exploring how these temperature fluctuations impact the crop's survival and yield. Conducted by a team at the Baodi District Meteorological Bureau and China Agricultural University, the study quantifies the effects of various low-temperature periods and durations on winter wheat's freezing resistance, particularly during its dormant phases.
Wheat (Triticum aestivum L.) ranks as the third-largest cereal crop globally, providing roughly 21% of the world’s food supply. Yet, winter wheat freeze injuries—resulting from prolonged periods of sub-zero temperatures—pose significant risks to its yield. With rising global temperatures, the traditional freeze resistance metrics used for evaluating winter wheat viability are becoming inadequate.
To effectively study this phenomenon, the researchers conducted controlled experiments from November 2016 to March 2017 at the Baodi District Meteorological Bureau, Tianjin, China. By simulating various low-temperature exposures using artificial chambers, they evaluated winter wheat under different scenarios, including early winter, mid-winter, and green-up periods.
The results indicated significant trends. The mortality rate of winter wheat tillers and yield reduction rates increase as the severity and duration of low temperatures rise, following what the study describes as an S-shaped curve. A remarkable observation was made during the early winter: 3The mortality rate of winter wheat tillers and the reduction rate of yield both increase with the decrease in temperature and the duration of low temperatures, following an S-shaped curve,3 noted the authors of the article.
Specifically, researchers found the freezing threshold temperatures for tiller mortality rate (RT) varied across different periods; they ranged from -11.7 to -17.9 °C for early winter, -9.4 to -15.6 °C for mid-winter, and -11.7 to -13.8 °C during the green-up phase. These stark statistics underline the vulnerability of winter wheat to changing temperature conditions, where 3the freezing resistance temperature of winter wheat is far lower than the intensity of low temperatures during the severe winter period,3 according to the study findings.
The experimental data demonstrated relationships where the winter wheat mortality rate during early winter correlates exponentially with soil effective negative accumulated temperature (SENAT), alongside linear correlations observed during mid-winter and the green-up phase. For the freezing thresholds based on different exposure durations—ranging from one to three days—the researchers established temperature limits directly affecting tiller survival and yield potential.
This comprehensive analysis not only highlighted the direct threat posed by climate-induced changes but also provided practical insights for agricultural management. By determining the specific freezing temperatures associated with varied levels of tiller mortality and yield reduction, the research aids farmers, policymakers, and agricultural scientists to devise strategic responses to mitigate future frost damages. Through these insights, winter wheat provisions, cultivation strategies, and resilience against frost can be effectively enhanced as the climatic factors evolve.
The research concludes on an imperative note, urging for adaptive agricultural practices and informed management of winter wheat cultivation, particularly as climate patterns continue to shift unpredictably. Establishing adaptive policies based on these findings will serve to fortify winter wheat's resilience against adverse weather, ensuring food stability moving forward.