Vol. 10, Issue 3 (2021)

Author(s):
Saidulu Yeluguri, Tejaswini Prakash, Sriram S, Seetharamu GK, Devappa V, Upreti KK and Mythili JB

Abstract:
A total of fifty five rose genotypes were screened against natural incidence of powdery mildew disease caused by Podosphaera pannosa, under a naturally ventilated polyhouse. Evaluation trial was conducted for two seasons during 2015-16 and 2016-17 to screen rose genotypes for their reaction to powdery mildew. The pooled apparent infection rate (r) of disease calculated for both seasons has showed a wide variation among genotypes. Based on per cent disease index (PDI), genotypes were categorized into different classes as tolerant (0-10 PDI), moderately tolerant (10.1-20 PDI), moderately susceptible (20.1-30 PDI) and highly susceptible (>40 PDI) to powdery mildew. Further, it was found that the accumulation of disease was low in case of moderately susceptible varieties compared to highly susceptible ones as indicated by the area under disease progression curve (AUDPC).