Record Details

GENETIC DIVERSITY AND BIOLOGICAL CONTROL OF Sclerotium rolfsii (Sacc.) CAUSING STEM ROT OF GROUNDNUT (Arachis hypogea L.)

KrishiKosh

View Archive Info
 
 
Field Value
 
Title GENETIC DIVERSITY AND BIOLOGICAL CONTROL OF Sclerotium rolfsii (Sacc.) CAUSING STEM ROT OF GROUNDNUT (Arachis hypogea L.)
 
Creator DURGA PRASAD, S
 
Contributor ESWARA REDDY, N.P
 
Subject GENETIC, DIVERSITY, BIOLOGICAL, CONTROL, Sclerotium, rolfsii, CAUSING, STEM, ROT, GROUNDNUT
 
Description Groundnut (Arachis hypogea L.) is a major legume and an
important oil seed crop in India, covering nearly half of the area under
oil seeds. Groundnut is affected by several diseases of which stem rot
caused by Sclerotium rolfsii Sacc. is an important disease with yield
losses of over 25 per cent.
A detailed study was carried on cultural, morphological and
pathogenic variabilities among the isolates of S. rolfsii. In vitro
antagonism of microflora isolated from seed and root habitats against
S. rolfsii and their compatibility with different fungicides. Molecular
characterization of S. rolfsii isolates by using RAPD and rDNA analysis
by ITS-PCR and ITS-RFLP.
Roving survey was conducted in Chittoor and Kadapa districts of
Andhra Pradesh to collect stem rot infected samples. The average
percent disease incidence of 10.38% in Chittoor and 17.84 per cent in
Kadapa was recorded. The pathogen was isolated from infected stem
bits of groundnut, purified and identified as S. rolfsii Sacc.
Among all the isolates, CSr 2, CSr 3, CSr 4, KSr 12, KSr 14,
KSr 15, KSr 16, KSr 17 and KSr 18 recorded the maximum growth
(90.00 mm). The least growth was observed in KSr 19 (62.67 mm). The
maximum growth rate was recorded in the isolate KSr 15 (34.50
mm/day) and least was recorded in KSr 19 isolate. Regarding sclerotial
size, the largest sclerotia was observed in isolate KSr 16 (2.2 mm) and
smallest was observed in CSr 4 (0.90 mm). Among the isolates KSr 18
produced more number of sclerotia (571/plate) and least was observed
in CSr 6 isolate (30/plate).
In pathogenic variability, the isolates CSr 4, KSr 19 and KSr 20
exhibited maximum per cent disease incidence (100%) while the isolate
KSr 13 and KSr 15 recorded the lowest PDI.
A total of 48 antagonistic microflora (8 fungi and 40 bacteria) were
obtained as seed and root endophytes from groundnut. Among the
8 fungal isolates, Trichoderma isolate (GSEF 3) inhibited the growth of
S. rolfsii to the extent of 65.18 per cent. Among the 40 bacterial isolates,
GSE 1, GSE 5 and GRE 29 showed 100 per cent inhibition of growth of
S. rolfsii followed by GSE 2 (93.33%), GSE 4 (86.29%), GRE 30 (85.55%)
and GRE 31 (82.22%). Culture filtrate experiment results showed that
the isolates GSE 1 and GRE 29 recorded the 100% inhibition of
S. rolfsii.
Different fungicides were tested in vitro for compatibility with
bioagents, mancozeb was found highly compatible with Trichoderma
isolate (GSEF 3). Among the bacterial isolates GSE 1 was more
compatible with mancozeb and less compatible with thiophanatemethyl.
The isolate GRE 29 also recorded more compatibility with mancozeb and
less in case of copper oxychlroide.
The RAPD banding pattern with random primers viz., OPA-01,
OPA-12, OPA-17, OPA-18 and OPA-20 reflected the genetic diversity
among the isolates with formation of 2 main clusters. Amplified ITS
region of rDNA with universal primers ITS-1 and ITS-4 produced
approximately 650-700 bp fragments as expected. ITS-RFLP results with
AluI, HinfI and MseI enzymes have not shown any polymorphism among
the isolates under the study.
 
Date 2016-08-11T14:43:32Z
2016-08-11T14:43:32Z
2008
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/72223
 
Language en
 
Relation D8410;
 
Format application/pdf
 
Publisher ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY, RAJENDRANAGAR, HYDERABAD.