Journal of Advances in Biology & Biotechnology

Sheath blight of rice caused by Rhizoctonia solani Kuhn is a deadly disease causing heavy devastation to the crop under favourable environmental conditions. An experiment was conducted at experimental area of AICRP on rice, at College of Agriculture, Rewa (M.P.) during Kharif 2018. In the present study, ten cultivars of rice were screened against sheath blight under artificial inoculations. A significant variation in length of lesions and relative lesion height (RLH) was recorded in all the tested cultivars. At 35 days after transplanting (DAT), the Lesion length ranged from 1.0 (P 1509) to 2.7 cm (P 1121), at 45 DAT it ranged from 2.1 (Kalikamod) to 4.2 cm (P 1121) and 4.2 cm (Chinnor) and finally at 55 DAT it ranged from 2.3 (Kalikamod) to 5.4 cm (P 1121). At 35 DAT, the RLH ranged from 5.9 (JRB1) to 19.6% (P 1509), at 45 DAT it ranged from 11.7 (JRB1) to 34.9% (PS5), and finally at 55 DAT it ranged from 17.8 (JRB1) to 66% (P 1509) were recorded. Incubation period varied from 48 to 108 hrs with a mean of 74.4 hrs. The data on apparent infection rate varied from 0.010 to 0.0265 with a mean of 0.0198 percent per day and the values of AUDPC varied from 137.7 to 370.0 with a mean of 270.1 were recorded. Among the tested cultivars of rice, Kalikamod and JRB1 were found highly resistant against sheath blight due to important disease variables viz., low lesion length, higher incubation period, lower apparent infection rate and AUDPC values under congenial microclimate. Three cultivars namely Luchai black, Chinnor and Jeera Shankar were found moderately resistant whereas, cultivars PS4, P1121, PS5, PS3 and P1509 were found susceptible to sheath blight under artificial inoculations. The resistant sources identified in the present study can be utilized in rice breeding programme against sheath blight disease.