Study on IAA Producing Rhizobacterial Isolates and Their Effect in Talc-Based Carrier on Some Plants
Compounds, known as hormones, are produced by rhizobacteria and are functionalized in growth promoting activity to the host plant. In this study, the production of Indole 3 acetic acid (IAA) by the plant growth promoting rhizobacteria (PGPR) was the main criterion in the strain selection to examine their plant growth promoting effects on plants. 12 bacterial strains were isolated from different fields of Kyaukse and Mandalay, Myanmar. Their biochemical characteristics were carried out by Bergey’s Manual of Determinative Bacteriology. IAA production of bacterial isolates were tested by the Salkowski’s method and analyzed by UV-Vis spectrophotometer. All isolates were found to produce IAA in a range from 30 ppm to 111 ppm and P6 produced the highest amount of IAA at 30th day. The talc based carrier formulation was used to extend the shelf life of selected isolates and this carrier maintained the bacterial population 105 cfu/g for 4 isolates and 104 cfu/g for the other isolates up to three months. According to the IAA productivity and one month shelf life data, P5, P6, P7, P8 and P10 were selected to determine their growth promoting activities of maize, betel and Kabuli chickpea plants. Among treatments, P7 isolate in talc based carrier which produced about 100 ppm IAA could enhance root formation significantly and P7 isolate also kept its high bacterial population in talc based carrier to 7×104 cfu/g up to four months.