Selection of potential rhizobacterial isolates from ginger rhizosphere against bacterial wilt caused by Ralstonia solanacearum

Selection of potential rhizobacterial isolates from ginger rhizosphere against bacterial wilt caused by Ralstonia solanacearum

2012

E06530

Eleven rhizobacterial isolates including the reference cultures of Pseudomonas fluorescens were evaluated for growth promotion and disease suppression in vitro based on various parameters viz., antagonism index, vigour index, hydrogen cyanide, ammonia and IAA production, 'P' solubilization and each was scored as per a modified standard score chart. Accordingly, the plant growth promoting index (PGPI) of 11 rhizobacteria were calculated based on the above six parameters and it was observed that four isolates out of 11 viz., RB-22, RB-144, RB-11 and RB-82 showed a PGPI of above 70 whereas the lowest index was recorded with RB-151. TLC analysis of growth regulators produced by the test isolates revealed that though all the cultures produced auxins and their related compounds, only two isolates viz., RB-141 and RB-11 produced both gibberellic acid as well as auxins. It was observed that all isolates produced considerable amounts of salicylic acid in varying amounts with the maximum by the two reference cultures followed by the isolates RB-11 and RB-22. The maximum number of antibiotics was produced by the isolate RB-22 comprising of pyoluteorin, pyrrolnitrin, pyocyanin and unidentified metabolite and this was closely followed by RB-144, RB-66, RB-11 and P.f2 which produced three antibiotics. The antibiotic 2, 4 DAPG was produced by RB-66, RB-11 and P.f2 apart from certain unidentified ones.

5(1):20-27, INTERNATIONAL JOURNAL OF PLANT PROTECTION

Research > Published Articles