Isolation and screening of rice rhizobacteria against bacterial leaf blight of rice

The bacterial leaf blight of rice caused by Xanthomonas oryzae pv.oryzae is the disease of great economic importance in Asia. Biological control of bacterial leaf blight disease can play a vital role in integrated rice disease management. In the present investigation isolation and screening of different rice rhizobacteria isolates were conducted and antagonistic activity were tested. Nineteen isolates were isolated from the rhizosphere of basmati rice i.e. susceptible variety of bacterial leaf blight of rice disease. All the nineteen isolates were screened in vitro for the antagonistic activity against Xanthomonas oryzae pv. oryzae (Xoo). Among the nineteen tested rice rhizobacteria (RRb) isolates against Xoo, three RRb isolates i.e. RRb 2, RRb 3 and RRb 4 showed inhibition zone at the site of antagonistic growth i.e. 0.767, 1.233 and 0.650 cm, respectively. The seed treatment with three effective isolates i.e. RRb2, RRb3 & RRb4, RRb3 and RRb4 provided good protection of seed against seed borne pathogens resulting increased seed germination and seedling vigour of rice varieties as compare to control.