National Academy of Agricultural Sciences (NAAS)
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PRINT ISSN : 2319-7692
Online ISSN : 2319-7706 Issues : 12 per year Publisher : Excellent Publishers Email : editorijcmas@gmail.com / submit@ijcmas.com Editor-in-chief: Dr.M.Prakash Index Copernicus ICV 2018: 95.39 NAAS RATING 2020: 5.38 |
The rotting of potato tubers is usually noticed from the time of planting till harvesting also in country stores as well as in cold stores. The proper isolation, pathogenicity testing and necessary characterization studies are very much essential for identification of actual causal organism which is very necessary for development of effective management strategy. In this context systematic studies were conducted in Department of Plant Pathology, College of Agriculture, Orissa University of Agriculture and Technology for isolation and characterization of bacterial pathogens causing soft rot of potato tubers which were collected from experimental plots of potato Research Project, Central Farm, OUAT, Bhubaneswar. From the rotted tissues the bacteria was isolated aseptically and pathogenicity was proved. Microscopic studies revealed the isolate was gram negative rod, non-capsulated with peritrichous flagella. Colonies on Nutrient Sucrose Agar medium were raised, convex, shining, white fluidal and slimy while grown on endo agar they found to be circular with initially pink coloured but later turning to deep red. The colonies on Tetrazolium Chloride medium were cream coloured. On Crystal Violet Pectate medium the bacterial masses produced deep cup shaped cavities on the petriplates. Biochemically, the response of isolates to ONPG, orinthrine and lysine was studied. Response for deamination, nitrate reduction, H2S production, citrate reduction recorded. Methyl red test was found to be positive while indole, melonate and esculin tests as negative. The isolate could ferment carbohydrates such as adonitol, rhamanose, trehalose, glucose, lactose while xylose, cellobiose, meliobiose, saccarose, raffinose not fermented. Furthermore, the isolates could express the presence of oxidase, not hydrolysed gelatine and starch. From all these studies it was confirmed that the causal organism was Pectobacterium carotovorum.
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