Disease Surveillance and Pathogenic Variability of Ascochyta Rabiei causing Blight of Chickpea in Punjab Pakistan

Abstract

Chickpea is an important legume crop and plays a significant role in global food security. Production is affected by many biotic and abiotic factors. The most significant biotic factor, Ascochyta rabiei is a fungal pathogen that causes Ascochyta blight in chickpeas, leading to substantial yield losses globally and is the primary cause in Pakistan. This pathogen causes heavy yield losses annually in the chickpea industry. The knowledge of the pathogenic variability of A. rabiei isolates can significantly impact the effectiveness of blight disease management strategies. A survey was conducted to collect blight samples to assess the pathogenic variability of A. rabiei isolates from different chickpea-growing regions of Punjab. The disease incidence and severity data were recorded using the quadrat square method in the fields. After isolation and purification, the pathogenicity test was conducted for conformation of the isolates. The virulence of ten isolates of A. rabiei was analyzed on six differential chickpea genotypes under artificial inoculation conditions in the glasshouse. The differential genotypes showed different levels of resistance and susceptibility to the isolates. Based on the reactions, the population of A. rabiei was grouped into different groups using a 1-9 rating scale. Only two isolates, BKR-01 and LAY-01, produced a high virulent effect against six germplasm. These isolates were collected from the Bhakkar and Layyah. The isolate MTN-1 were categorised as the least virulent. At the same time, the remaining isolates showed a moderate level of reaction.