Screening for sheath blight (Rhizoctonia Solani Kühn) resistance in rice (Oryza Sativa L.)

Rice is one of the most important and widely cultivated food crops of the world and the majority of rice (90 per cent) is being produced in Asian countries with China and India being the major producers (IRRI, 2013). Rice varieties, parental lines of the hybrids and the hybrid in general are susceptible to several biotic stresses such as bacterial blight (BB), blast, brown plant hoppers (BPH) and Sheath blight (ShB), resulting into dramatic reduction in the yield as well as the quality of rice (Singh et al., 2011). ShB is the soil-borne fungal disease caused by Rhizoctonia solani Kuhn, which alone accounts to 25 per cent of yield losses (Kumar et al., 2009). Wide host range of the ShB pathogen makes the management of the disease a difficult task. Till date, no rice germplasm in the world has been found to be completely resistant to this fungus as the resistance is typically governed by polygenes (Sha and Zhu, 1989). Six parents viz., FL 478, IW Ponni, BPT 5204, IR 64, RNR 57979 and TETEP utilized in the present study were subjected to screening for Sheath Blight resistance along with susceptible check, T (N) 1. Screening was done both under field as well as in screen house with artificially inoculated condition. The screen house facility that was available at Department of Plant Breeding and Genetics, ADAC and RI, Trichy was utilized for artificial screening of diseases and the entries in the present study were evaluated for sheath blight disease.