Integrated approaches for the management of rice sheath blight disease caused by Rhizoctonia solani Kuhn
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Date
2019
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Department of Plant Pathology Naini Agricultural Institute, Faculty of Agriculture, Sam Higginbottom University of Agriculture, Technology and Sciences, (Formerly Allahabad Agricultural Institute) Prayagraj-211007 (U.P.), India
Abstract
Rice (Oryza sativa L.) is the world’s important food crop of Asian origin. Among different fungal diseases of rice, sheath blight caused by Rhizoctonia solani has currently become one of the most important disease on all the major high yielding rice varieties. Loss due to the disease has been estimated up to 69 per cent. An attempt was therefore made and twenty four isolates of Rhizoctonia solani were collected from the disease samples from fifty nine different rice growing areas of Prayagraj. Identification was carried by studying their morphological characters. Molecular analysis based on URP-PCR showed that the genetic variability of the isolates was low and they were almost clonal. Relative correlations between geographical origins of isolates and molecular grouping were observed but there was no correlation between virulence assays and DNA patterns. A pot experiment was carried out to check virulence assay of all R. solani isolates. Maximum number of affected/dead tillers (6.33), number of lesions (9.0), mean lesion length (19.0 cm) and relative lesion height (45.37 cm) was recorded with RS_U22, RS_U49, RS_U7 and RS_U22, Efficacy of different selected bio-agents and fungicides was evaluated on different growth and yield parameters of rice crop under field condition at prayagraj. Minimum disease intensity @ 5 DAI (17.87%), 10 DAI (20.20%), and 15 DAI (30.03%), maximum shoot length @ 30 DAT (14.31 cm), 60 DAT (24.63 cm) and 120 DAT (28.88 cm), dry shoot weight (64.82 g), number of tillers @ 45 DAT (20.75), root length @ 90 DAT (16.99 cm), dry root weight (2.99 g) and grain yield (48.51 q ha-1) was recorded with the treatment combinations of Trichoderma harzianum seed treatment+ Propiconazole foliar spray and Carbendazim seed treatment + Propiconazole foliar spray as compared to control (untreated check).
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Ph. D. Thesis
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