First Report on Physiological Races of Phakopsora pachyrhizi Syd Causing Asian Soybean Rust in India

First Report on Physiological Races of Phakopsora pachyrhizi Syd Causing Asian Soybean Rust in India

The physiological variability studies were carried out for 17 isolates collected from different growing environment of India. Three pathotypes were identified based on physiological variability on 13 international set of differentials namely Cluster I-Reddish Brown (RB) lesion producing pathotypes, Cluster II- TAN lesion producing pathotypes and Cluster III- Mixed or RB + TAN producing pathotypes. Based on the reaction of Phakopsora pachyrhizi isolates on two differentials PI 230971 and PI 200492, Race 2 produced RB type lesions on PI 230971 and TAN type on the other differentials and Race 3 produced TAN type lesion PI 200492 and RB type lesion on the other differentials were identified. Based on reaction on these two differentials, Race 2 and Race 3 are prevalent in Karnataka state while, only Race 2 was prevalent in Maharashtra and north eastern states...