Development of Plant Growth Promoting Microbial Consortium Based on Interaction Studies to Reduce Wilt Incidence in Cajanus cajan L. Var. Manak

Abstract

Abstract: The present study was undertaken to develop a plant growth promoting microbial consortium on the basis of interaction studies to reduce the fusarium wilt in Cajanus cajan. All strains were exposed to interact under in vitro conditions. Three strains viz. Pseudomonas fluorescens LPK2, Sinorhizobium fredii KCC5 and Azotobacter chroococcum AZK2 did not inhibit each other. In vitro dual culture studies on the interaction of one strain to another, revealed no mutual growth inhibition among S. fredii KCC5, P. fluorescens and A. chroococcum AZK2. Spectrophotometric studies also showed that the individual growth of these strains was not affected in combined cultures, where strains were cultured together. The optical density values of S. fredii KCC5, P. fluorescens LPK2 and A. chroococcum AZK2 were observed in present studies were at par with their treatments when incorporated into the broth and vice versa. A complete inhibition of the conidial and chlamydospores germination Fusarium udum was observed by the culture filtrates of S. fredii KCC5 and P. fluorescens LPK2. The culture filtrates of S. fredii KCC5 and P. fluorescens LPK2 inhibited conidial germination significantly (P>0.01). The inhibition of germ tube was more pronounced than that of conidial germination. A highly significant effect (P>0.01) of the non-volatile metabolites was noted against the conidial germination and germ tube growth of the test pathogen. A corresponding amount of culture supernatant from F. udum grown in potato dextrose broth initiated a significant chemotactic response of S. fredii KCC5,