RÉSUMÉ
The work entitled “Progression of powdery mildew of Indian mustard (Brassica juncea L.) in relation to weather parameters” was carried out in Agriculture Research Farm, Banda University of Agriculture & Technology, Banda, Uttar Pradesh, India during Rabi 2020-21 season. As infection and development of a disease depends on the favourable environmental conditions hence, relationship between powdery mildew of Indian mustard and weather factors was evaluated in Ganga, Varuna, Giriraj and RH-0749 varieties of Indian mustard in which maximum temperature between 25-30°C, minimum temperature >10°C with minimum relative humidity (RH) <50% favoured the development of powdery mildew in all the four varieties Indian mustard varieties. Individual and combined effects of different weather parameters on development of powdery mildew was evaluated using correlation and regression analysis. Percent disease index (PDI) of powdery mildew was positively correlated with the maximum and minimum temperature whereas, it was negatively correlated with maximum RH, minimum RH and rainfall in Indian mustard varieties Ganga, Varuna, Giriraj and RH-0749. Coefficient of determination (R2) explained that 96, 96, 95 and 96 % powdery mildew development was influenced by the maximum temperature, minimum temperature, maximum relative humidity, minimum relative humidity and rainfall in Indian mustard varieties Ganga, Varuna, Giriraj and RH-0749, respectively. Multiple linear regression equation was developed to find out the expected PDI of the disease based on the predictor weather variables. Correlation analysis explained that warmer temperature and lesser humidity favoured the development of powdery mildew in Indian mustard. Multiple linear regression model developed in current investigation may be utilized for development of powdery mildew prediction model in Indian mustard.