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STUDIES ON VARIABILITY AND CHARACTERIZATION OF ISOLATES OF Pythium aphanidermatum (Edson) Fitz. IN TOMATO

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Title STUDIES ON VARIABILITY AND CHARACTERIZATION OF ISOLATES OF Pythium aphanidermatum (Edson) Fitz. IN TOMATO
 
Creator SAILAJA RANI, J
 
Contributor REDDI KUMAR, M
 
Subject STUDIES, VARIABILITY, CHARACTERIZATION, ISOLATES, Pythium, aphanidermatum, Fitz, TOMATO
 
Description Six isolates of Pythium aphanidermatum were collected from tomato
nurseries of different geographical areas in Rayalaseema region and
designated as CTR1, CTR2, KDP1, KDP2, KNL1 and KNL2. Among different
solid media, potato dextrose agar, supported maximum growth. Among the
isolates, CTR1 recorded maximum colony diameter. Variation in mycelial,
sporangial and oospore characters among six isolates of P. aphanidermatum
revealed that the isolates CTR1, KDP1 and KNL1 produced fluffy aerial
mycelium with inflated sporangia, whereas CTR2 and KDP2 produced
moderately abundant surface mycelium with lobulate sporangia and KNL2
produced sparse aerial mycelium with lobulate sporangia. Among the isolates
CTR1 was highly virulent causing maximum per cent disease incidence while
the isolate CTR2 was least virulent causing less per cent disease incidence.
Dual culture studies indicated that among the four native Trichoderma
harzianum isolates, T. harzianum-1 was found to be effective. Among the two
antagonists of T. harzianum-1 and P. fluorescens, T. harzianum-1 recorded
maximum per cent inhibition of all isolates of pathogen. Maximum inhibition
was observed in CTR2 when T. harzianum was used while P. fluorescens
recorded maximum inhibition in KDP2. Compatability studies revealed that
metalaxyl at 500 and 1000 ppm was found to be superior to other fungicides in
inhibiting the pathogen.
The polyacrylamide gel electrophoresis (PAGE) analysis revealed
variations in protein fractions among the isolates. SDS-PAGE profiles of
proteins of six isolates indicated that CTR2 was found to be unique by having
one additional band with a molecular weight of 8 kda and it was absent in the
remaining five isolates. Native PAGE profiles of esterase enzyme revealed
that the absence of band with a Rm value of 0.40 in the isolate CTR2. Based
on Jaccard's similarity co-efficients, the six isolates of P. aphanidermatum
could be divided into four groups.
Management studies revealed that seed treatment with combination of
T. harzianum-1 and P. fluorescens was found to be effective in controlling pre
and post-emergence damping-off.
 
Date 2016-08-19T10:02:35Z
2016-08-19T10:02:35Z
2005
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/72940
 
Language en
 
Relation D7722;
 
Format application/pdf
 
Publisher ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY, RAJENDRANAGAR, HYDERABAD