Variability in rhizoctonia solani kühn, the causal agent of sheath blight of rice and its management
| dc.contributor.advisor | M. K. Naik | |
| dc.contributor.author | Nagaraju P. | |
| dc.date.accessioned | 2016-07-26T10:58:36Z | |
| dc.date.available | 2016-07-26T10:58:36Z | |
| dc.date.issued | 2013 | |
| dc.description.abstract | The sheath blight of rice caused by Rhizoctonia solani (Kuhn.) is considered as major bottleneck in successful production of rice in irrigated tract of Tungabhadra Project area of north eastern zone of Karnataka. The study comprising survey on prevalence and incidence of sheath blight of rice, collection of sheath blight pathogenic isolates for exploring cultural, morphological and molecular variability, evaluation of rice genotypes, influence of planting density, nitrogen level, botanicals and biocontrol agents and IDM against sheath blight of rice was also attempted. The study identified pockets in Bellay, Koppal and Raichur districts under TBP area affected by moderate to severe incidence of sheath blight compared to Cauvery belt areas in Mysore, Shimoga and Mandya during kharif 2006 and kharif 2007. The diversity with respect to morphological and cultural characters of 32 isolates of R. solani on PDA revealed that the maximum radial growth of mycelia was noticed in isolates RS-14, RS-16 and RS-18 each with 89.33 mm. Based on the morphological and cultural characteristics, the isolates of R. solani were grouped into four and designated as G1, G2, G3 and G4 where as the molecular analysis of variability using RAPD primer indicated two major clusters such as C1 and C2 comprising 15 and 17 isolates, respectively. Among 139 rice genotypes screened under field condition, Aditya, Ajaya, Swarnadhan, Nidhi and Vikramarya were found resistant by registering 1 grade. In the management of disease with fungicides, botanicals and bioagents, Hexaconazole, Validamycin and Carbendazim, Tricure (Azadirachtin 0.03%), P. fluorescens (Pfr-l) were found effective in managing sheath blight. Application of 200 kg N per ha recorded higher disease severity (40.37%) and increased further with higher levels of nitrogen (350 kg/ha) when compared to plots with recommended nitrogen and zero nitrogen fertilizer applications. Among different planting densities, the Systematic Rice Intensification (SRI) method was found effective in reducing severity of sheath blight (5.00 PDI) when compared to other planting (16.12 PDI). In IDM trial, use of moderately resistant cultivar IR 64 with spray of hexaconazole @0.1% was found effective in managing sheath blight disease as compared to Samba mahsuri. | en_US |
| dc.identifier.uri | http://krishikosh.egranth.ac.in/handle/1/69867 | |
| dc.publisher | UAS Dharwad | en_US |
| dc.sub | Plant Pathology | |
| dc.these.type | Ph.D | |
| dc.title | Variability in rhizoctonia solani kühn, the causal agent of sheath blight of rice and its management | en_US |
| dc.type | Thesis | en_US |