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Subject: Plant Pathology × Author: Anand V.Halakeri × End date: 2013 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Studies on serodiagnosis, epidemiology and management of sunflower necrosis viral disease in Northern karnataka
    (UAS Dharwad, 2006) Anand V.Halakeri; A.S.Byadgi
    Sunflower necrosis is a major virus disease of sunflower caused by Tobacco Streak Virus. It was first reported from Kolar district of Karnataka State during 1997. The roving survey for disease incidence in Northern Karnataka was undertaken and disease map was developed, which revealed the presence of disease in all the three seasons. The disease was severe in Bijapur, Raichur and Koppal districts showing 15-20 per cent incidence. Infected plants showed mosaic, marginal necrosis and malformation of leaves, calyx and earhead, early infected plants showed partial seed filling. TSV -S had wide host range and its Thermal Inactivation Point was 45°C, Dilution End Point 10-4 and Longevity in vitro of 8 h. The epidemiological studies indicated positive correlation of disease with thrips population and also with maximum temperature. The virus was purified by extraction in Phosphate buffer, PEG precipitation, density gradient centrifugation and ultra centrifugation. Electron microscopic observations revealed isometric shaped particles in decoration method. Immunizing rabbit with purified TSV -S produced the antiserum. SDS-P AGE revealed 30 Kda Protein band when stained with coomassie brillant blue. Direct Antigen Coating Enzyme Linked Immuno Sorbant Assay indicated presence of virus particles in samples of sunflower, cowpea, peas, green gram, tomato, soybean, black gram and red gram but not in seeds of diseased plant. In Immunodiffusion test precipitation line appeared around wells containing diseased samples. RT-PCR yielded 800 bp length coat protein gene. The disease had a drastic effect on yield parameters of sunflower. Germplasm lines GMU-209, GMU-244, GMU-249, and GMU-259 exhibited some degree of tolerance properties with less than 10 per cent disease incidence. Crop could be protected from heavy loss due to virus infection by Imidacloprid seed treatment (@ 5 g/kg) + spray (@ 0.25 ml) at 30, 45 and 60 days after sowing and sorghum as border crop.