Biochemical Characterization of Native Fluorescent Pseudomonads and its Suitable Carrier Material for Mass Multiplication in Kuttanad Ecosystem

Bacterial antagonist fluorescent pseudomonads for sheath blight disease were isolated from different locations in Kuttanad region. Three effective strains viz., PF 43, PF 46 and PF 47 were tested along with standard culture P 1 against sheath blight disease of rice under glass house condition. The confirmation tests viz., physiological and biochemical characterization of the efficient isolates were carried out at Rice Research Station, Kerala Agricultural University, Moncompu. Various physiological tests on growth at different pH, Iron toxicity and Aluminium toxicity level showed that the isolate PF 43 grew at pH ranging from 1.0 to 14 and tolerated upto 1000 ppm of iron toxicity and 90 ppm of aluminium toxicity level. The biochemical tests indicated that three efficient isolates were confirmed as gram negative, rod shaped, fluorescent in King's B medium and positive response for growth at 4°C, Levan formation, Gelatin liquefaction and Catalase tests. However, there was a negative response for growth at 41°C, Methyl red, VogesProskaur and Indole tests. Thus, based on morphological and biochemical characteristics, the isolated strains were identified to be Pseudomonas fluorescens. P. fluorescens PF 43 product survived upto 150 days with required population of 1.01 to 1.63 × 10⁸ cfu per g in talc, dolomite and gypsum based formulations. At 240 days of storage, 1 × 10⁷cfu were detected in talc, dolomite and gypsum based formulations. The cheap and easily available carrier material, gypsum and dolomite can be used for mass production of native P. fluorescens and is recommended to 66,000 ha rice growing tracts of Lower, Upper and Karilands of Kuttanad regions like Alleppey, Kottayam and Pathanamthitta District for ecofriendly management of diseases.