Effect of environmental factors on Phytophthora nicotianae var. nicotianae and evaluation of bell pepper germplasm

摘要

Temperature and relative humidity are the most important variables which affect leaf blight and fruit rot of capsicum. Temperature was found to be significantly negatively correlated and relative humidity was significantly positively correlated with disease severity. The coefficient of determination (R2) revealed that weather variables contributed 80 and 85 per cent towards the disease severity during 2010 and 2011, respectively. Out of 36 and 115 lines of capsicum evaluated under field conditions and in vitro, respectively, 9 lines namely Chilli 52530, Feroz, Kandaghat Selection, Jins Joy, Nandita, SP-461, Sel-9, SP-701 and UHF-14 were found resistant either under in vitro or field conditions. Infection rate (r) and AUDPC was observed very less inresistant as compared to susceptible lines. Mean AUDPC in resistant genotypes varied between 19.5 to 33.5. In susceptible cultivars average AUDPC values were in the range of 449.0 to 782.0. Infection rate for resistant genotypes was in range of 0.33 to 0.54/week while for highly susceptible genotypes the value ranged between 0.77 to 1.12/week.