ARS | Publication request: MOLECULAR ANALYSIS OF ASCOCHYTA RABIEI (PASS.) LAB., THE PATHOGEN OF ASCOCHYTA BLIGHT IN CHICKPEA (CICER ARIETINUM L.)

Submitted to: Journal of Theoretical and Applied Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: July 17, 2000
Publication Date: N/A

Interpretive Summary: Ascochyta blight is considered the most important disease of chickpea worldwide and control is often through the use of resistant varieties. Unfortunately, the fungus is highly diverse and is capable of changing genetically to produce disease under varying conditions. Also, it is known that the fungus differs in the various production regions worldwide. In this study we assessed the degree of genetic diversity in isolates of the fungus that had been collected in several countries including the US. Variation was identified among the isolates and that variation made it possible to cluster the isolates into geographic regions of origin. Knowing the particular strain of the fungus and its frequency geographically provides specific information needed by researchers and fieldmen to recommend specific deployment of resistant varieties and recommendations for effective management of the disease over a wide area.

Technical Abstract: To determine degree of genetic diversity in Ascochyta rabiei (Pass.) Lab. That causes ascochyta blight in chickpea, 37 Indian, five USA, three Syrian, and two Pakistani isolates were subjected to RAPD analysis. A total of 48 polymorphic RAPD markers were scored in the isolates and the data was used for cluster analysis. Most of the isolates were clustered essentially according to geographic origin in the dendrogram. Based on th two major clusters A and B, Indian isolates were grouped into two categories, type-A and type-B. Isolates of A. Rabiei within Punjab state are more diverse than isolates from other states in Northwest part of India. A DNA marker, specific to Indian isolates was identified. This is the first report of molecular diversity analysis Indian isolates of A. Rabiei. This information on genetic diversity within Indian populations of A. Rabiei may assist Indian chickpea breeders in proper deployment of blight resistant cultivars and disease management.