Does cyclic water stress damage wheat yield more than a single stress?

Area of Science:

• Agricultural Science
• Plant Physiology
• Climate Change Adaptation

Background:

• Climate change is increasing the frequency of water stress events impacting global crop production.
• Winter wheat (Triticum aestivum L.) is a vital crop susceptible to yield losses from various water stress conditions.

Purpose of the Study:

• To investigate the effects of mild and severe cyclic/single water stress (drought and waterlogging) at different growth stages (elongation and heading) on winter wheat yield.
• To determine the impact of combined stresses and stress severity on wheat yield reduction.
• To identify key yield-determining factors affected by water stress.

Main Methods:

• Conducted three experiments simulating cyclic drought, cyclic waterlogging, and combined cyclic drought and waterlogging.
• Applied mild and severe water stress treatments at the elongation and heading stages of winter wheat.
• Quantified yield losses and analyzed impacts on kernel number, spike weight, total biomass, and harvest index.

Main Results:

• Single water stresses significantly impacted wheat yield, with severity correlating to yield loss.
• Extreme drought or waterlogging at the elongation stage caused greater yield penalties than at the heading stage.
• Cyclic water stress, except for mild drought and mild waterlogging combined, significantly decreased yields. Severe cyclic drought and waterlogging caused the highest yield reductions (71.52% and 73.51%).
• Drought during elongation reduced kernel number; waterlogging/drought at heading or elongation reduced spike weight.

Conclusions:

• The type, degree, and timing of water stress critically influence winter wheat yield.
• Understanding complex water stress interactions is essential for developing climate-resilient wheat production strategies.
• Repeated or severe water stress events, particularly cyclic severe drought and waterlogging, pose significant threats to wheat yield.