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Y. SANDHYA*, C.P.D. RAJAN, A. RANGA RANI AND M. MAHENDRA
Department of Plant Pathology, S.V. Agricultural College, ANGRAU, Tirupati – 517 502, Chittoor Dt., Andhra Pradesh
Pseudomonas fluorescens isolates NLR-B1, NLR-B2, NLR-B3 were tested in dual culture against R. solani among which NLR-B3 isolate was found effective under in vitro against Rhizoctonia solani than other two isolates. Sclerotial germination was tested after incubating in NLR-B3 bacterial suspension at concentrations ranging from 10-4 to 10-8 CFU/ml, there was no inhibi-tion in sclerotial germination at 10 min incubation at all concentrations of bacterial suspension, where as at 20 min incubation, inhibition of sclerotial germination was 73.33 per cent at 10-4 concentration, 43.33 per cent at 10-5 concentration, 30.00 per cent at 10-6 concentration and there was no inhibition of sclerotial germination at 10-7 and 10-8 concentrations. At the incubation period of 30 min. inhibition in sclerotial germination was 53.33 per cent at 10-4 concentration, 36.67 per cent at 10-5 concentration, 30.00 per cent at 10-6 concentration. Similar inhibition of 13.33 per cent was observed both at 10-7 and at 10-8 concentration. The inhibition percentage increased with increase in concentration of bacterial suspension at 20 and 30 min incubation periods. The addition of higher concentrates bacterial suspensions to soil containing sclerotia with further incubation for 10 days and subse-quent retrieval showed the bacterial germination inhibition of 56.67 per cent at 10-4 concentration, 36.66 per cent at 10-5 concen-tration and 16.66 per cent at 10-6 concentration. However at lower concentration of 10-7 and 10-8 there was no inhibition of sclerotial germination. The results indicated a significant increase in per cent inhibition of sclerotial germination with increase in concentration of the bacterial suspension.
Pseudomonas fluorescens, Rhizoctonia solani, Sclerotia, dual culture.