Protecting cotton crops under elevated CO₂ from waterlogging by managing ethylene

Area of Science:

• Agricultural Science
• Plant Physiology
• Environmental Stress Biology

Background:

• Soil waterlogging in cotton (Gossypium hirsutum L.) triggers ethylene release, leading to developing fruit abscission.
• Understanding cotton's response to environmental stressors like waterlogging and elevated CO2 is crucial for crop resilience.

Purpose of the Study:

• To investigate the impact of waterlogging and elevated CO2 (eCO2) on fruit production in a linted (Empire) and lintless (5B) cotton cultivar.
• To determine if mitigating ethylene action can improve cotton performance under waterlogging stress.
• To assess the interaction between waterlogging, ethylene inhibition, and eCO2 on cotton fruit set and development.

Main Methods:

• Glasshouse study exposing cotton genotypes (Empire and 5B) to a 9-day waterlogging event and eCO2 (700 ppm).
• Inhibition of ethylene synthesis using aminoethoxyvinylglycine (AVG) before waterlogging.
• Measurement of ethylene release, fruit abscission rates, and fruit production under different treatment conditions.

Main Results:

• Waterlogging significantly increased ethylene release in both genotypes but inhibited fruit production primarily in Empire.
• Aminoethoxyvinylglycine application reduced waterlogging-induced fruit abscission, particularly in the Empire cultivar.
• The lintless mutant (5B) showed limited fruit damage despite increased ethylene, suggesting genetic disruption of ethylene metabolism conferred tolerance.
• Elevated CO2 enhanced fruit production in both genotypes, with a more pronounced effect in the 5B mutant.

Conclusions:

• Ethylene plays a key role in waterlogging-induced fruit abscission in cotton, especially in linted cultivars like Empire.
• Genetic modification (lintless mutant 5B) or chemical inhibition of ethylene can mitigate waterlogging damage.
• Elevated CO2 can enhance cotton fruit production, and this benefit is amplified in genotypes with altered ethylene metabolism or greater sink capacity (5B).