Vol. 12, Issue 7 (2023)

Author(s):
Sonal Kumar, RKS Tiwari, VK Nirmalkar, PK Keshri and Jayant Sahu

Abstract:
Bacillus spp. is an important member of biological agent which generally used as bio control agents against number of foliar, seed borne and soil borne diseases of cereal, pulses and vegetables. Excess of salt in some parts of Indian soil creates problem of using bio agents due to detrimental effect of salt on bacterial growth and development. Application of bio agents in salinity affected area requires tolerance towards salinity. In present investigation different novel isolates of Bacillus spp. found effective against Rhizoctonia solani and Sclerotium rolfsii in vitro were tested for their tolerance towards different NaCl concentration (salinity level). Isolates were grown in different NaCl concentrations (salinity level) i.e. 5%, 10%, 15% and 20%. Growth and development of bacteria were recorded in terms of optical density (OD) and colony forming units (CFUs/ml). Higher growth of isolates at salinity level 5 per cent indicated the possibility of using such isolates in saline soil for plant growth promotion and suppression of diseases. Salt tolerance towards 20% NaCl concentration recorded (OD) in isolate B. velezensis (BI 36) (0.042), B. subtilis (BI 68) (0.042) and B. subtilis (BI 72) (0.042) followed by BI 44 (0.034) and B. velezensis (BI 43) (0.032). At 20% NaCl concentration, maximum CFUs were observed in isolate B. velezensis (BI 36) (5.8 × 10⁶ CFUs/ml) followed by B. subtilis (BI 72) (5.7 × 10⁶ CFUs/ml), B. subtilis (BI 68) (5.6 × 10⁶ CFUs/ml) and B. tequilensis (BI 22) (4.8 × 10⁶ CFUs/ml), which indicates salt tolerant characteristics of these isolates.