Effect of temperature and pH on morphological and cultural variation of Ascochyta rabiei, the blight pathogen of chickpea in India

Ascochyta rabiei, causal agent of blight in chickpea is a highly variable pathogen because of the existence of two mating types. Study was conducted on the temp and pH dependent cultural and morphological variation among seven A. rabiei isolates from the north western plain zone (NWPZ) and north hill zone (NHZ) of India. The optimum temp and pH for the growth of majority of the isolates studied was 20-25 C and 6.0-7.0, respectively. The isolates differed in their colony colour, mycelial intensity, pycnidia and pycnidiospore production and these variations were characteristic of each isolate with respect to temp and pH.