Comparative Assessment of Fungal Pathogenicity in Different Small Millet Cultivars

Small millets belonging to the Poaceae family are widely adaptable to different rainfall zones. Studies were conducted on four varieties of small millets viz., finger millet (PRM1 & PRM2), proso millet (PRC1) and barnyard millet (PRJ1) that differ in the morphological and pathological diversity of fungus affecting them. The infected samples were collected from Minthi and Laoli, villages in Pauri Garhwal, Uttarakhand, India. From these samples, three fungal isolates were obtained, which were identified as Curvularia lunata, Alternaria alternata, and Botrytis cinerea. During natural infection, C. lunata and A. alternata were found to infect the PRM1 variety of finger millet, whereas B. cinerea infects the PRM2, barnyard and proso millet. During pathogenicity studies, barnyard millet, and proso millet were widely affected by the fungal isolates, whereas PRM1 and PRM2 variety of finger millet was found to be resistant. Cross-inoculation tests showed that the isolates of C. lunata from finger millet infects all varieties of small millets. Physiological and biochemical parameters were reduced under stressed conditions except anthocyanin. An increment was found in glutathione peroxidase, proline, and peroxidase activity,whereas catalase activity was reduced under stressful environments. Maximum sporulation was detected on lesions incubated at 36°C (75×104 conidia ml-1 ) for 24 hours. Botrytis cinerea displayed maximum growth at 25°Cwhereas Curvularia lunata and Alternaria alternata depicted maximum growth at 30°C on Potato Dextrose Agar medium. The leaf wetness duration of 36 and 48 h produced significantly higher severity compared to 24 hours duration.