Interactive effects of herbicides and weeds on wheat (Tritcium aestivum) under drought stress: a physiological, biochemical, and yield attributes-based approach

Weed infestation and drought stress are major biotic and abiotic constraints to global agricultural productivity, causing substantial yield losses and escalating management costs. Weeds alone contribute to an predicted annual economic loss of USD32 billion, while drought can reduce crop productivity by nearly 50%, posing a serious threat to food security. In the perspective of Sustainable Development Goals SDG-2 (Zero Hunger) and SDG-13 (Climate Action), this 2-year study (2022-2023) evaluated the impact of drought stress on the efficacy of the herbicide (clodinafop + metsulfuron) against the weeds Phalaris minor and Medicago denticulata in wheat (Triticum aestivum). Herbicide was applied to well-watered (WW) and drought-stressed (DS) environments, 10 days after irrigation was withheld in the DS treatments. Results indicated a significant reduction in herbicide efficacy under DS, with a greater reduction observed against M. denticulata, leading to poor weed management. The survival of weeds under DS conditions elevated oxidative stress in wheat, particularly in the presence of M. denticulata, which caused higher reactive oxygen species accumulation and greater yield losses compared with P. minor. A clear association was observed between weed biomass, oxidative damage, and yield reduction. The findings highlight that wheat is more vulnerable to M. denticulata under drought, emphasizing the need to consider environmental interactions in designing effective and climate-resilient weed management strategies.