Plant growth promotion of radish by rhizosphere dwelling bacteria

Abstract

The present study was carried out with the aim to develop a plant growth-promoting rhizobacterial inoculant for improving the growth of radish. A total of 20 rhizobacteria were isolated and then tested for multifarious plant growth-promoting traits. The isolates exhibited tricalcium phosphate and zinc solubilization, production of siderophores, auxins, ammonia, and growth on different nitrogen-free media. Out of 20 isolates, two potential bacterial isolates, RM3 and RL3, identified as Bacillus and Pseudomonas, respectively, were selected based on PGP traits to evaluate their potential to promote the growth of radish under pot conditions. In greenhouse experiment, these isolates, when used as a consortium, showed a significant improvement in soil enzymatic activities (viz. dehydrogenase: 12.99 μg TPF formed h-1 g-1 of soil, alkaline phosphatase: 11.94 μg PNP formed h-1 g-1 of soil and urease: 401.65 μg urea hydrolysed formed h-1 g-1 of soil) and plant growth parameters (shoot length: 38.76 cm, leaf area: 267cm2, fresh leaf weight:106.05 g, dry leaf weight:1.23 g, number of leaves per plant: 23, fresh root weight:111.69 g, dry root weight: 2.06 g, root length: 34.04 cm and root diameter: 3.33
cm) relative to control as well as other bioinoculants. This study concludes that using these two potential rhizospheric isolates as a consortium would improve the soil health and yield of radish.