The production of indole-3-acetic acid (IAA) by these bacteria was determined using Salper’s reagent (Gordon and Paleg, 1957).Three milliliters of fresh Salper’s reagent (1 mL 0.5 M FeCl3 in 50 mL 37% HClO4 ) was added to free-cell supernatant and kept in complete darkness for 30 min at room temperature, and the optical density at 535 nm was measured in each treatment (Wöhler, 1997).A standard curve was also prepared for IAA determination.