Pathogenic variability and characterization of pearl millet blast pathogen Pyricularia pennisetigena

Blast is one among the serious diseases affecting pearl millet foliage and yield. Identifying the Blast isolates causing severe damage to crop is very critical to develop resistant genotypes. This study was conducted during 2023 and 2024 at the Research Farm of Rasi Seeds (Pvt) Ltd, Toopran, District Medak, Telangana, India wherein isolates were obtained from the major cultivated areas of Telangana, Uttar Pradesh, Maharashtra and Rajasthan. Uniform Blast Nursery (UBN) screening was deployed on 11 pearl millet genotypes by inoculating with the five isolates individually. Blast severity scores on ICMB03555, ICMB11666, ICMR12888 and ICMB97111 indicated the differential reaction of the isolates. Among the five isolates, isolate collected from Jaipur (RJ1) has high virulence score of 7.0. Molecular identification of the most virulent isolate was carried out by using ITS primers. The ITS-rDNA partial sequence was amplified by utilising ITS4 and ITS5 primers. Morphological characterisation of virulent isolate showed greyish brown blast fungus with globose to sub-globose colonies with irregular margin and pyriform conidia confirming Pyricularia. Virulent Isolate (RJ1) sequence data of ITS4 and ITS5 primers is in alignment with 99.80% similarity with Pyricularia pennisetigena (NFCCI accession number: 4864). Most virulent isolate RJ1 collected from Jaipur was identified as P. pennisetigena which has huge potential to affect grain and fodder yield.