Wheat-kernel growth characteristics during exposure to chronic ozone pollution

Area of Science:

• Agricultural Science
• Environmental Science
• Plant Physiology

Background:

• Chronic ozone (O(3)) air pollution is known to reduce crop yields.
• Limited information exists on O(3) stress effects on wheat kernel development.

Purpose of the Study:

• To investigate the impact of chronic O(3) exposure on kernel-growth components in two soft red winter-wheat genotypes.
• To determine the relationship between O(3) levels and key kernel development parameters like kernel-growth rate (KGR) and kernel-fill duration (KFD).

Main Methods:

• Field study with five air-quality treatments, including controlled charcoal-filtered air (CF) and varying levels of O(3) addition.
• Spike samples collected at multiple time points after anthesis (DAA).
• Kernel-growth rate (KGR), kernel-fill duration (KFD), effective filling period (EFP), and assimilate utilization (AU) were analyzed using linear and quadratic models.

Main Results:

• Ozone exposure significantly reduced KGR and AU, with higher O(3) levels causing greater reductions.
• Genotype Severn exhibited a longer KFD than MD5518308, but O(3) did not significantly affect KFD or EFP in either genotype.
• O(3) effects on kernel weight varied by genotype, impacting MD5518308 early and Severn later in development.

Conclusions:

• Decreased economic yield in wheat due to chronic O(3) exposure is primarily attributed to a reduction in kernel-growth rate (KGR).
• Understanding genotype-specific responses to O(3) stress is crucial for developing resilient wheat varieties.
• Ozone pollution poses a significant threat to wheat production by impairing kernel development.