Enhancing Drought Tolerance in Two Soybean Genotypes with Varied Susceptibilities Through Foliar Application of Acetic Acid

Abstract

AbstractSoybean is a very important food legume because of its high protein and oil concentrations. However, soybean is vulnerable to drought stress, which has become more severe and occasional in many regions worldwide. To alleviate drought’s influence, the application of certain agents is increasingly gaining attention as it is economically affordable and practically applicable. Acetic acid (AA) is, by far, one of the cheapest agents that are reported to have potential benefits against drought; however, no accurate data on its influence on soybean genotypes differing in their drought tolerance are published. An experiment was conducted in a controlled environment to evaluate the effects of AA on the morpho-physiology of two soybean (Glycine max (L.) Merr.) genotypes: drought-tolerant ‘Speeda’ and drought-susceptible ‘Coraline.’ Chlorophyll-a and total carotenoids, stomatal conductance, and specific leaf area of both soybean genotypes decreased under water deprivation conditions. However, AA application enhanced these traits significantly. Drought reduced the optimal and the actual photochemical efficiency of PSII of ‘Coraline,’ but not ‘Speeda.’ The application of AA could not enhance the relative water content of both genotypes. Root and shoot morphology were negatively influenced by drought in both genotypes; however, AA helped in restoring these traits in ‘Coraline,’ but not ‘Speeda,’ indicating that AA application might be more beneficial in the case of drought-susceptible soybean genotypes.