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BIOLOGICAL CONTROL OF Aspergillus flavus Link ex Fries CONTAMINATION IN GROUNDNUT AND MOLECULAR CHARACTERIZATION OF POTENTIAL ANTAGONISTS

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Title BIOLOGICAL CONTROL OF Aspergillus flavus Link ex Fries CONTAMINATION IN GROUNDNUT AND MOLECULAR CHARACTERIZATION OF POTENTIAL ANTAGONISTS
 
Creator DILEEP KUMAR, K
 
Contributor ESWARA REDDY, N.P
 
Subject fungi, groundnuts, mycotoxins, diseases, biological development, biochemical compounds, planting, pathogens, sowing, irrigation
Aspergillus flavus Link ex Fries, GROUNDNU, POTENTIAL ANTAGONISTS
 
Description Groundnut is an important oil-seed crop of tropical and sub-tropical
regions of the world. Among the fungal diseases aflatoxin contamination due
to invasion by A. flavus is potentially very destructive with respect to export of
groundnut and its products. In the present study an integrated management
package was formulated against A. flavus in groundnut using biocontrol agent.
The pathogen is a saprophyte or facultative parasite and produce green
colored conidia on artificial medium. Five types of aflatoxins have been
reported viz., B1, B2, G1, G2 and M, among them aflatoxin B1 (AFB1) is more
carcinogenic and occur more commonly.
The pathogen was isolated from rhizosphere soil of groundnut by serial
dilution technique and identified as A. flavus.
Fourteen isolates of antagonistic mycoflora were isolated from
groundnut rhizosphere soil, geocarposphere, root endophyte and seed
endophyte by using serial dilution technique. The antagonistic mycoflora were
identified as Trichoderma isolates and designated from T1 to T14.
In vitro screening of Trichoderma isolates (T3, T5, T7, T8, T11 and T14)
against A. flavus by dual culture indicated that native Trichoderma isolate T7
was found to be significantly superior over others in inhibiting the growth of A.
flavus to the extent of 70.36 per cent, besides the isolate T7 performed well at
high temperatures (37ºC) compared to other isolates.
The efficacy of potential antagonistic Trichoderma isolate -7 (T7), was
tested in pot culture against A.flavus in groundnut. The results revealed that
treatment under irrigated condition possess low level of A.flavus population
and having maximum population of Trichoderma when compared to drought
and was found to be effective in reducing the per cent seed infection and also
aflatoxin content.
Trichoderma isolates T3, T5, T7, T8, T11 and T14 differing in their
antagonistic activity were selected for Molecular Characterization by RAPD
and ITS-PCR.
The RAPD banding pattern reflected the genetic diversity among the
isolates with the formation of two main clusters. The potential Trichoderma
isolate T7 a separate group within the cluster II. Amplified ITS region of rDNA
with universal primers ITS-1 and ITS-4 produced 600 bp which confirmed that
all the isolates were Trichoderma.
 
Date 2016-06-02T11:19:06Z
2016-06-02T11:19:06Z
2010-07
 
Type Thesis
 
Identifier http://krishikosh.egranth.ac.in/handle/1/66622
 
Language en
 
Relation D8955;
 
Format application/pdf
 
Publisher ACHARYA N.G. RANGA AGRICULTURAL UNIVERSITY