Dr. T. S. S. K. PATROPALLAVI TATINENI2024-05-062024-05-062024-05-06D6562https://krishikosh.egranth.ac.in/handle/1/5810208719In 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.EnglishThesis