Vol. 11, Issue 3 (2022)

Author(s):
Kota Chakrapani, Bireswar Sinha, W Tampakleima Chanu, Tusi Chakma and Bijeeta Thangja

Abstract:
Sheath blight, caused by Rhizoctonia solani Kuhn, is one of the most devastating diseases incurring huge losses in the production of rice crop. It is important to investigate both morphological and molecular comparative studies among the isolates of R.solani The collection of R.solani isolates from symptomatic rice plants was done and analyzed for morphological and molecular characterization from root to the tip to have a clear idea on the causal agent and the disease. Morphological studies on growth on R.solani viz., radial growth, mycelial characters, sclerotial characters, growth of fungus at different pH levels and molecular studies using RAPD and ISSR markers were analyzed. Morphological features which includes radial growth (18.95-45mm), sclerotial characters (brown to dark brown), fresh and dry weights (5.08- 6.78g and 0.25-0.52 respectively), growth at different pH levels (0-4.30g), growth in different culture media (26.50-44.50mm) had a varied significance. Mycelial compatibility studies of all possible 45 combinations revealed 15 compatible and 30 incompatible isolates by having certain degree of aversion. At deeper levels molecular variability studies were done using molecular markers 10 RAPD and 10 ISSR primers which revealed that isolates were clustered to two clusters at 49% degree of similarity, Similarly, ISSR analysis revealed that isolates were clustered to two clusters at 39% degree of similarity. Our results suggest that, the presence of different races of R. solani within the same local geographic regions makes the disease vulnerable and lay huge losses in production.