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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 |
Alternaria leaf blight is one of the most important yield reducing diseases of Bt-cotton caused by Alternaria macrospora. In order to find bio-based ecofriendly effective control measure to this phytopathogen, 114 rhizospheric bacterial isolates were screened for in vitro antifungal potential against Alternaria leaf blight phytopathogen using modified dual culture method. Out of 114 isolates tested, 18 rhizospheric bacterial isolates inhibited growth of Alternaria macrospora in vitro. Highest antifungal activity was exhibited by isolate RLS19 (91.43 %) and followed by RLS52 (88.57 %), RLS18 (85.71 %), RLS102 (85.71 %), RLS76 (82.86 %), RLS96 (82.86 %) in dual culture technique against the phytopathogen. Based on inhibition activities in dual culture assay, 8 efficient rhizospheric bacterial isolates were selected for further investigation. For characterizations of microbial control mechanism, rhizospheric bacterial isolates were tested for production of volatile metabolites, diffusible metabolites and siderophore. Volatile metabolite production was detected by double plate assay. Rhizospheric bacterial isolate RLS76 hamper 17.77 % radial growth by producing volatile metabolites against phytopathogen while other isolates were unable to produce volatile metabolites. Diffusible metabolite production was detected by agar well diffusion method. Rhizospheric bacterial isolates RLS19 and RLS76 showed highest (71.43 %) inhibition of phytopathogen by producing diffusible metabolites followed by RLS18 (68.57.00 %), RLS52, RLS56, RLS96, RLS102 (65.71 %) and RLS53 (57.14 %). Siderophore production ability was detected qualitatively by modified CAS agar plate method. All the tested, 8 rhizospheric bacterial isolates were able to produce siderophore. The highest siderophore was recorded by RLS18, RLS53 and RLS58.