DISTRIBUTION, DIVERSITY AND ANTAGONISTIC ABILITY OF ACTINOBACTERIA FROM BLACK PEPPER (Piper nigrum L.) RHIZOSPHERE

Abstract

A survey was undertaken in the major black pepper growing belts of Kerala and Karnataka for studying the distribution and diversity of actinobacteria in the rhizosphere of black pepper. A total of 129 morphologically different actinobacteria were isolated from 123 samples collected from different agro climatic niche. The 129 actinobacteria were morphologically characterized on the basis of the colour of aerial mycelia, substrate mycelia, spore chain morphology and production of diffusible pigments. The isolates were also tested for their antagonistic ability against major pathogens of black pepper. Morphologically the isolates fall into 7 groups in which majority were found to be in the genus Streptomyces (100). Other groups are Actinoplanes (10), Micromonospora (10), Nocardiopsis (2), Actinomyces (3), Actinopolyspora (1), and Dactylosporium (1). Functionally, more than 50% of the isolates showed 51-94% inhibition against the major pathogens. Key words: Actinobacteria, Antagonism, Black pepper, Diversity, P. capsici, Rhizosphere, Spore chain morphology