Pathogenic variations of Pyricularia grisea population causing blast of finger millet (Eleusine coracana) in India

Introduction: Blast of finger millet is an important disease causing significant loss in production and marketingof the crop worldwide. Information on virulence diversity in present population of blast pathogen of this crop in Indiais lacking. Objectives: The objective of the present study was to assess extent of pathogenic variations in Pyriculariagrisea population adapted to finger millet in India, and to identify key isolates for artificial screening of finger milletlines for blast resistance. Methods: A total of 125 finger millet genotypes originated from different countries were preliminarily screenedunder natural field conditions against blast in three hot spots locations for selection of a subset of 50 genotypes.The subset was artificially inoculated under controlled conditions with six isolates of P. grisea and based on blastreactions, a set of seven host differentials lines were identified. P. grisea isolates from across India were tested onthe differential set for assessment of virulence. Results: Thirty-seven isolates were grouped into ten pathogenic groups or pathotype based on virulent/ avirulentdisease reactions suggesting existence of wide variability in virulence in blast population. Four out of tenpathogenic groups were designated as key pathotype that can be used for rapid screening under greenhouseconditions. A multi-pathotype resistant accession IE4734 is a potential source of blast resistant genes that can beused in finger millet breeding programme. Conclusion: This study has identified a set of seven host differential lines and ten pathotypes in the Pyriculariagrisea population adapted to finger millets. Four (p1 to p4) are key pathotypes and these can be used for rapidscreening under greenhouse conditions. © 2023, Indian Phytopathological Society.