Effect of water deficit stress on benzoylprop-ethyl performance and physiological traits of winter wild oat (Avena sterilis subsp. ludoviciana)

Abstract Increasing the diversity in the sites of action of herbicides is an important method for delaying and preventing herbicide resistance in weed populations. Benzoylprop-ethyl, a lipid biosynthesis inhibitor, is used to increase the diversity of herbicide sites of action and control ACCase- and ALS-resistant Avena sterilis subsp. ludoviciana (Durieu.) Gillet & Magne) populations in Iran. Drought stress, especially in arid and semiarid areas, affects weed physiology and performance of herbicides. Accordingly, a series of dose-response assays was conducted to evaluate the efficacy of benzoylprop-ethyl under drought- (60% Field Capacity) and non-drought-stress (90% Field Capacity) conditions on A. sterilis subsp. ludoviciana. Also, some biochemical and physiological traits of A. sterilis subsp. ludoviciana including leaf chlorophyll content, leaf greenness index, photosynthesis rate and stomatal conductance were investigated under the drought and non-drought regimes. The efficacy of benzoylprop-ethyl decreased significantly under drought condition. The effective dose reducing dry weight by 90% in relation to the untreated control (i.e., ED90) for the drought-stressed plants was significantly (P