CHARACTERIZATION OF BANDED LEAF AND SHEATH BLIGHT PATHOGEN AND ITS MANAGEMENT IN BARNYARD MILLET
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Date
2024-05-06
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Acharya N G Ranga Agricultural University
Abstract
In the present investigation on “Characterization of banded leaf and sheath
blight pathogen and its management in barnyard millet”, the banded leaf and
sheath blight (BLSB) affected leaf samples were collected from different millet
growing regions of India and the pathogen was isolated. Initially, seven different
media were used to study their effects on morpho-cultural characteristics of the
pathogen among which Potato Dextrose Agar (PDA) was found to support best
radial growth of the pathogen in addition to production of highest number of
sclerotial bodies and hence was used to carry out further morpho-cultural
characterization studies for all the isolates.
Morpho-cultural characterization studies revealed that, there was
considerable variation among the isolates in various morpho-cultural characters
like radial growth, colony colour, colony texture, hyphal width, sclerotia size,
sclerotia weight, distribution of sclerotia, pattern of arrangement of sclerotia,
sclerotia texture and sclerotia colour. Molecular characterization using ITS1/ITS4
primers revealed that all the isolates belong to AG1-IA group of Rhizoctonia solani
and there was no much variability among the isolates collected from different
geographical locations which depicts the genetic flexibility and adaptability of the
pathogen to spread to new ecological niches. Pathogenic variability was studied
for all the 10 isolates and the incubation period varied from 4 to 8 days. The isolate,
RAP-2 was more virulent. Correlation analysis between different morpho-cultural
characters and virulence of the isolates revealed that isolates with higher radial
growth were more virulent and also there exists a significant positive
correlation between sclerotia size and sclerotia number, hyphal width.
Yield loss assessment studies revealed that the potential yield loss caused
by the pathogen ranged from 54% to 62%. Integrated management studies
include screening for host resistance, evaluation of different treatments viz.,
chemicals viz., propiconazole @ 0.1%, tebuconazole + trifloxystrobin @
0.05%, biocontrol agents viz., Trichoderma asperellum, Pseudomonas
xvii
fluorescens, Bacillus subtilis, biorational viz., panchagavya against banded leaf
and sheath blight disease. The study identified the genotypes, VBBC-340, VB 19-3, VB-19-4, as resistant and seed treatment and foliar spray with
tebuconazole + trifloxystrobin @ 0.05% as the most effective among the
treatments tested.