Identification and Evaluation of Antagonistic Potential of Different Fluorescent Pseudomonads in Northern Plains of West Bengal.

To achieve future food security, reliable crop protection will be critically important. Development of biological control for soil borne disease is accepted as a safe, durable and ecofriendly alternative for chemical management strategy. Pseudomonads possess many traits like production antibiotics, lytic enzymes, siderophores, hydrogen cyanide (HCN) that make them well suited as biocontrol and growth-promoting agents. An attempt was taken to isolate and identify different fluorescent Pseudomonads and to evaluate their antagonistic ability. Twelve fluorescent Pseudomonads isolates were collected from different crop rhizosphere from different locations of northern parts of West Bengal. Isolates characterized morphologically and biochemically. All the isolates were gram negative rods with smooth and glossy colony on kings B and nutrient agar medium with convex elevation but variation was found in respect to pigment production. A huge variation was found in respect to biochemical characterization. From the result of biochemical analysis, the isolated sp. can be identified as Pseudomonas fluorescens or Pseudomonas putida or Pseudomonas aeruginosa. Some of the isolate produce green, some isolates produce yellowish green and rest of them produce red/pink pigments. Isolates showed a huge variation in respect to pathogenicity against soil borne pathogen Slerotium rolfsii. Percent inhibition varied from 31 to 74 %. Isolate 3 and 8 can be efficient biocontrol agent as highest growth inhibition of the pathogen Sclerotium rolfsii was obtained by the isolate 8 (74.37%) followed by isolate 3 (63.15%). In respect to growth parameter isolate 8, 9 and 10 were found better among the isolates where as in respect to disease reduction isolate 3, 8, 9 and 11 were promising under in vivo study. [ABSTRACT FROM AUTHOR]