The Reactions of MungbeanLines to Isolates of Cercospora canescens

Abstract

A factorial experiment in RCB with 5 replications was conducted to observe reaction of 7 mungbean lines against 10 isolates of C. canescens collected from various mungbean planting areas to designate physiological races of the pathogen. The results showed that difference in disease severity between lines varied acording to the isolate. Seven physilolgical races were finally designated on the basis of their pathogenicity on a set of differential lines. Race 2 which was composed of the isolates of Nakhon Sawan, Roi Et and Chiang Mai was the most pathogenic of all, causing severe symptoms in all lines. The prominent infection ability and crecosporin toxin of the isolates were responsible for such severity.