All the 20 isolates were screened for IAA production. In brief, test
bacterial culture was inoculated in the nutrient broth containing L- tryphtophan
(5 μg/mL), incubated at 28 ± 2°C for 5 days. Cultures were
centrifuged at 3,000 rpm for 30 min and two mili liter of the supernatant
was mixed with two drops of orthophosphoric acid and 4 mL of
Salkowaskis reagent (50 mL, 35% perchloric acid; 1 mL 0.5 M FeCl3).
Appearance of red color indicates IAA production. OD(optimum density)
was measured at 535 nm using spectrophotometer and shown as
μg/mL [