Author(s):

Arun K Yadav, Anita Kumari and Arshad Anwar

Abstract: Rice is a monocotyledonous annual grass belonging to the family Gramineae and the genus Oryza. It includes 20 wild species and two cultivated species: Oryza sativa (grown throughout the world) and Oryza glaberrima (grown only in Africa). Total yield loss in rice due to rice diseases in the world is 10-25%. In India, total yield loss due to diseases in rice is 35%, in which blast costs 25% loss, sheath blight 20%, BLB 10%, tungro and other diseases 45%, Rhizoctonia solani was isolated from sheath blight diseased rice plants and Koch’s postulate was established for pathogenicity and then purified and maintained for further study. The results of presented in this investigation were conducted under laboratory and field conditions. In the present study we isolated Rhizoctonia solani from the rice variety Rajendra Kasturi plant showing symptom of sheath blight from BAU farm Sabour, Bhagalpur. Morphological and Cultural characterization of R. solani was studied by visual observation of mycelia and sclerotia colour and its size. Hyphal width ranged from 4.75 μm to 7.43 μm and sclerotial colour changed from brown, light or dark brown, and black brown. The diameter of sclerotia ranged from 1.13- 2.03 mm. Mycelia of isolated pathogen were light brown during early growth and produced large amounts of aerial hyphae throughout the growth cycle. Sclerotia were tan when young, generally dark brown when mature, and up to 1.5 mm in diameter with clumps up to 5 mm in diameter. Some sclerotia clumps were found on the agar surface but most clumps and individual sclerotia were embedded in the agar. Our observations are in complete with the findings of the numerous workers. Isolated the Rhizoctonia solani from infected plant and studied its morphological or cultural characteristic as sclerotia colour was light brown, brown, dark brown and deep dark brown.

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