Paclobutrazol and Salicylic Acid Application Ameliorates the Negative Effect of Water Stress on Growth and Yield of Maize Plants

Growth and yield of maize is seriously restricted by water deficit. Salicylic acid (SA) andPaclobutrazol (PBZ) induces biotic and abiotic stress tolerance in crops. In order to evaluate effect ofantitranspiration substances and water stress on growth, yield and yield components of maize (Zeamays L.) an experiment was conducted in 2009, Hamedan, Iran. The experiment was laid out inrandomized complete block design with split plot arrangement. The plants were sprayed with thesalicylic acid (0.5 mM) and paclobutrazol (50 ppm). The results showed that vegetative growth indicessuch as total dry weight, leaf area index and crop growth rate, was considerably affected byapplication of SA and PBZ under different irrigation regimes. Interaction between SA and 100, 70 and40% of full irrigation significantly increased grain yield by15.85, 20.81, 29.74 percentage, weight of1000 seeds by 11.40, 15.77, 20.17 percentage and biological yield by 15.41, 19.38, 23.19 percentagecompared to untreated plants, respectively. Grain yield and 1000-grain weight significantly decreasedunder PBZ treatment by 8.60, 8.64 percentage compared to untreated plants under non-water stress.Grain yield and weight of 1000 seed displayed a significant increase in response to rate of the PBZcompared to untreated plants under low and high water stress. Exogenous SA application wasadvantageous under three irrigation levels, but exogenous PBZ application was advantageous onlyunder stress conditions.