Effect of weather parameters on powdery mildew development of wheat at different location in Himachal Pradesh

Abstract

Powdery mildew (Blumeria graminis f sp. tritici) is the most important among diseases of wheat after stripe rust and leaf rust in northern Hill Zone. The disease development is highly affected by environmental conditions, especially the temperature and relative humidity. Keeping this in view, the powdery mildew development was studied in five wheat varieties PBW 343, HPW 155, HD 3086, VL 829 and HS 490 (commercially grown varieties in NHZ and NWPZ) along with susceptible check genotype Lehmi at two nationally important hotspot locations of CSKHPV i.e. HAREC, Kukumseri (Summer 2016) and Rice and Wheat Research Centre, Malan (Rabi season 2016–2017). The disease severity was correlated with maximum temperature, minimum temperature and mean relative humidity (RH). The disease development was more at Kukumseri which may be due to the prevalence of conducive mean minimum and maximum temperature of 13.4 °C and 23.6 °C, respectively and moderate RH (45.1%). However, disease development was less at Malan. The prevailing mean minimum and maximum temperature and RH were 7.8 °C, and 28.9 °C and 63.5%, respectively at Malan. It is apparent from the studies that powdery mildew development was favoured by temperature of 45% RH. Multiple correlation of coefficients between maximum temperature, minimum temperature and RH were significant in both the environments. The coefficient of determination (R2) revealed that selected weather variables contributed 15–59% and 94–99% towards the terminal disease severity (TDS) at Malan and Kukumseri, respectively. Hence, the crop grown at Kukumseri may be the most vulnerable for disease development under field conditions.