Status and screening of brown leaf spot of rice in districts of Madhya Pradesh

Rice (Oryza sativa L.) is a staple food for nearly half of the world's population. Its production is significantly affected by various biotic stresses, with fungal diseases causing major economic losses. One such disease is brown spot, caused by the Deuteromycetes fungus Bipolaris oryzae (teleomorph Cochliobolus miyabeanus), which is a significant challenge in all rice-growing regions. Given the significance of brown spot disease in rice, the current investigations aimed to: know the status of the disease and screen various rice varieties for their resistance to brown spot. A roving survey was conducted to determine the incidence and severity of brown leaf spot disease of Madhya Pradesh. The survey studied revealed that the disease was present in most of the areas, with incidences ranging from 6.52 to 32.51 per cent and severity from 7.14 to 39.54 per cent. One hundred rice varieties were screened to determine their response to the brown spot pathogen. The results indicated that only one variety, JRH-19, was highly resistant. Sixty varieties were moderately resistant, with 5.1 to 25 percent of the leaf area affected. One variety, Kranti, was found to be highly susceptible to brown leaf spot disease.