Characterization and Antagonistic Potential of Rhizospheric Microbes from Organic Cardamom Production System

Small cardamom (ElettariacardamomumMaton), the “Queen of Spices” is a zingiberaceous spice, native to the moist evergreen forests of Western Ghats, South India. Among the debilitating diseases, rhizome-root rot incited by Rhizoctoniasolani, Pythium vexans and Fusarium oxysporum is widespread across the cardamom growing tracts and possess enormous destructive potential. Nonjudicious application of synthetic chemicals to manage this disease could create imbalance in the environmental equilibrium, contamination of soil, water bodies and might result in bio-magnification and organic-based production system could be the appropriate approach in order to nullify the deleterious effects of synthetic molecules. In the present study, attempts were made to isolate, characterize and assess antagonistic potential of microorganisms associated with cardamom rhizosphere against rhizome-root rot pathogens. Twelve fungi and six bacteria were isolated from the rhizosphere of cardamom grown under organic system. The fungal isolates were characterized morphologically based on colony characters, growth pattern and spore morphology. Whereas, the bacterial isolates were characterized based on the criteria such as colony appearance Gram’s staining and response to various biochemical reactions. In the in vitro bioassay for antagonistic efficacy against the test pathogens, among the fungi isolate 3 was found to be superior in inhibiting all the test pathogens, while the bacterial isolate 2 proved to be effective against R. solaniand P. vexans. Further identification of the efficacious isolates viz., fungal isolate 3 and bacterial isolate 2 based on ITS and rDNA sequencing, placed them in the genus Trichoderma and Chromobacterium, respectively.

Author(s): Chinthana KL, Biju CN, Ankegowda SJ and Srinivasan V

Abstract | PDF

Share This Article