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ISOLATION AND CHARACTERIZATION OF Pseudomonas fluorescens FROM RICE FIELDS FOR THE BIOLOGICAL CONTROL OF Rhizoctonia solani CAUSING SHEATH BLIGHT IN RICE

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Title ISOLATION AND CHARACTERIZATION OF Pseudomonas fluorescens FROM RICE FIELDS FOR THE BIOLOGICAL CONTROL OF Rhizoctonia solani CAUSING SHEATH BLIGHT IN RICE
 
Creator BIYYANI SUMAN
 
Contributor VIJAYA GOPAL DEPARTMENT, A
 
Subject ISOLATION, CHARACTERIZATION, RICE FIELDS, BIOLOGICAL, CONTROL, CAUSING SHEATH, BLIGHT , RICE
 
Description Sheath blight is a devastating disease caused by Rhizoctonia solani Kuhn in rice
crop. Biocontrol agents have great demand now-a-days as they are replacing chemical
pesticides to a large extent as they are cost effective, ecofriendly and easily available.
Pseudomonas fluorescens is one among them which not only enhances the plant growth but
also controls the fungal pathogens by production of anti fungal metabolites. Present
investigation is focussed towards isolation of fluorescent Pseudomonas from rice
rhizosphere and in vitro, in vivo evaluation of antagonistic activity of these isolated
fluorescent Pseudomonas against Rhizoctonia solani causing sheath blight in rice crop.
Thirty Pseudomonas fluorescens isolates were isolated from rice rhizospheric soils
of twenty two villages of Parigi and Doma mandals of Rangareddy district, Telangana as
the district has severe sheath blight incidence. Latitude, longitude, elevation, GPS numbers
of the place of collection of soil samples are recorded and point map has been generated by
using Arc GIS software and rectification of the toposheets was done by Erdas image 9.3
software. The isolates are purified by observing under UV light and they were culturally,
morphologically and biochemically identified as Pseudomonas fluorescens according to
Bergey’s manual of Determinative Bacteriology. Biochemical characterization revealed
that all the isolates were positive for catalase, oxidase, citrate utilization, gelatine
liquefaction, denitrification and negative for indole tests. These isolates were screened in
vitro for Plant growth promoting attributes like phosphate solubilizatin, siderophore, IAA,
ammonia and HCN production. Results revealed that 76.67% isolates solubilized
phosphorous and produced siderophores. 93.33% isolates produced IAA and all the thirty
isolates i.e., 100% produced ammonia and HCN.
All the isolates were further screened in vitro for antagonistic activity against the
fungal pathogen Rhizoctonia solani causing sheath blight and found that all isolates
inhibited the fungal pathogen and highest inhibition was found with the organism DMP1
(53.43%).
Pot culture experiment was conducted for in vivo evaluation of Pseudomonas
fluorescens against the challenge inoculated rice crop by using various methods of
inoculation. Results revealed that seed treatment method of application of Pseudomonas
fluorescens with the isolate DMP1 effectively controlled and reduced the disease severity
of 42.56% at 60 DAT, 41.12% at 70 DAT and 40.81% at 80 DAT caused by the
Rhizoctonia solani compared with the other methods of inoculation. Seed treated plants
especially with the organism DMP1 not only controlled the disease but improved the
growth parameters like plant height (56 cm, 74 cm and 82.6 cm at 30,60 and 90 DAT
respectively), Leaf area index (4.71 at 60 DAT), chlorophyll content (39.60 and 48.17 at 30
and 60 DAT ) and yield parameters like number of tillers (13.7, 17.3 and 17.3 at 30,60 and
90 DAT), panicles (13.7 at 90 DAT) and grain yield per plant (32.69 gms) followed by root
dipping and foliar method of application of biocontrol agents. When the methods of
inoculation are compared seed treatment method improved the growth and yield parameters
in the challenge inoculated rice crop. When the challenge inoculated plants are scored for
the disease, it was observed that the seed treated method of inoculation to the rice showed
resistance towards the disease with a score of 1.2.
 
Date 2016-09-09T14:42:00Z
2016-09-09T14:42:00Z
2015
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/76258
 
Language en
 
Relation D9817;
 
Format application/pdf
 
Publisher PROFESSOR JAYASHANKAR TELANGANA STATE AGRICULTURAL UNIVERSITY