Record Details

INTEGRATED MANAGEMENT OF DRY ROOT ROT OF CHICKPEA AND MOLECULAR CHARACTERIZATION OF POTENTIAL BIOCONTROL AGENTS

KrishiKosh

View Archive Info
 
 
Field Value
 
Title INTEGRATED MANAGEMENT OF DRY ROOT ROT OF CHICKPEA AND MOLECULAR CHARACTERIZATION OF POTENTIAL BIOCONTROL AGENTS
 
Creator NAGARJUNA REDDY, G
 
Contributor ESWARA REDDY, N.P
 
Subject diseases, fungi, vegetative propagation, planting, chickpeas, biochemical compounds, fungicides, drying, bacteria, pathogens
 
Description Chickpea (Cicer arietinum L.) is one of the major grain legume pulse
crop of India covering 40% of area under pulse crops. Chickpea is affected by
Rhizoctonia bataticola (Taub) Butler. causing dry root rot an important
disease with yield losses ranging from 10 to 100 per cent.
A roving survey was conducted in Kadapa and Kurnool districts of
Rayalaseema region, Andhra Pradesh for the incidence of dry root rot of
chickpea. In vitro antagonism of microflora isolated from rhizosphere and
root habitats against Rhizoctonia bataticola and their compatibility with
different fungicides was studied. In vitro evaluation of fungicides against
pathogen, integrated management of Rhizoctonia bataticola and molecular
characterization of potential biocontrol agents by using RAPD and 16S rDNA
analysis was also carried.
A roving survey was conducted on dry root rot incidence in six major
chickpea growing mandals of Kadapa and Kurnool districts, A.P. and the
incidence was ranged from 6.22 to 13.50 per cent with lowest and higest
incidence in Rajupalem and Sanjamala mandals, respectively.
The Pathogen was isolated from infected plant showing typical dry
root rot symptoms viz., withering and drying of the plants, presence of dark
tap root showing signs of rotting and devoid of its lateral and finer roots,
purified and identified as Rhizoctonia bataticola.
A total of 23 antagonistic microflora (8 fungi and 15 bacteria) were
obtained from rhizosphere soil and root endophytes from chickpea. Among 8
fungal isolates, Trichoderma isolate-3 (T3) inhibited the growth of
Rhizoctonia bataticola to the extent of 57.83 per cent. Among the 15 bacterial
isolates REB-8 inhibited the growth of Rhizoctonia bataticola to the extent
of 76.47 per cent followed by RB-1 (74.11%) and REB-9 (71.76%).
In vitro efficacy of four fungicides viz., thiram, copper oxychloride,
captan and carbendazim was evaluated against Rhizoctonia bataticola using
poisoned food technique at different concentrations. Carbendazim was found
to be effective as it completely inhibited the mycelial growth even at lower
concentration. Thiram was found to be next best fungicide.
In vitro compatibility of four fungicides used against R. bataticola
were tested on potential antagonist REB-8 at different concentrations by
using spectrophotometric method. The carbendazim showed high
compatibility followed by thiram and copper oxychloride, whereas captan
was found to be less compatible with REB-8.
The efficacy of potential biocontrol agent (REB-8) and compatible
fungicide (carbendazim) was tested in pot culture against dry root rot of
chickpea. The results revealed that treatment T6 (soil application with
potential biocontrol agent + soil drenching with fungicide) was superior in
reducing per cent disease incidence and increasing plant growth parameters,
like root length, shoot length, dry weight of shoot and root when compared to
other treatments.
The RAPD banding profiles with random primers viz., OPA-11, OPA-
12, OPA-14, OPA-18 and OPD-3 reflected the genetic diversity among the
antagonistic bacterial isolates with formation of two main clusters. Amplified
16S rDNA with universal primers 63F and 1387R produced approximately
1300 bp fragments as expected. 16S rDNA-RFLP results with Taq I enzyme
showed no polymorphism among isolates under the study. The 1300bp
amplified product of 16S rDNA from potential biocontrol agent i.e., REB-8
was cloned into the vector and sent for sequencing to MWG technologies,
Bangalore.
 
Date 2016-06-24T14:07:11Z
2016-06-24T14:07:11Z
2010
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/67959
 
Language en
 
Relation D8725;
 
Format application/pdf
 
Publisher ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY