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Subject: Plant Pathology × Author: Pankaj × Start date: 2001 × Type: Thesis × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    Occurrence and variability of Magnaporthe grisea inciting blast disease of pearl millet [Pennisetum glaucum (L.) R. Br.]
    (Chaudhary Charan Singh Haryana Agricultural University hisar, 2022) Pankaj; Vinod Kumar
    The present study entitled, ―Occurrence and variability of Magnaporthe grisea inciting blast disease of pearl millet [Pennisetum glaucum (L.) R. Br.]‖ was carried out in laboratory and screen house Department of Plant Pathology, CCS Haryana Agricultural University, Hisar. The study was aimed to know the occurrence and severity of pearl millet blast disease in Haryana, morphological, molecular and pathogenic variability among M. grisea isolates and chemosensitivity of different isolates of M. grisea. The maximum pearl millet blast incidence and severity was in Bhiwani district followed by Mahendragarh district whereas, minimum was in Nuh district during both the years. All the collected M. grisea isolates showed a considerably variation in cultural and morphological characters and pathogenic behaviour. Among all the isolates the maximum radial growth 42.00 mm was recorded in isolate Mg 12 followed by Mg 10 (41.67mm) and Mg 11 (41.33 mm) whereas, the minimum radial growth of 22.00 mm was recorded for Mg 4 isolate. The maximum average length of the spores (35.21 μm) was also observed in Mg 12 isolate which is significantly higher among all the isolates followed by Mg 10 (33.49 μm) and Mg 11 (31.58 μm). Mg 4 isolate (22.98 μm) showed a minimum average length of spores. Among all the fungal isolates Mg 4 isolate was found to be least pathogenic with 39.75 per cent disease severity followed by isolate Mg 6 (40.00%). The isolates Mg 12 (60.29 %), Mg 11 (57.51 %) and Mg 10 (56.84 %) were recorded most pathogenic. All the isolates showed high level of polymorphism. The cluster analysis based on ISSR primers the isolate Mg 4, Mg 6 and Mg 16 were most diverse and isolates Mg 10 and Mg 12 had the highest similarity coefficient (1.00) among the all 16 M. grisea isolates. The high relative humidity more than 90 %, Temperature 25-30°C and slightly acidic pH (6.0) favours the growth and sporulation of Magnaporthe grisea under in vitro conditions. Among the fungicides evaluated propiconazole reported maximum inhibition of the mycelial growth (91.48 %) of the fungus followed by Tebuconazole as it showed 76.17 per cent growth inhibition. The both the chemicals were significantly superior over carbendazim (68.21 %) which was found to be the least effective in inhibiting mycelial growth of the fungus.