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2019 - 201912020 - 20221
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Subject: Plant Pathology × Author: Pankaj × Start date: 2001 × Type: Thesis ×
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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.
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    ThesisItemOpen Access
    Studies on epidemiology and management of yellow vein mosaic virus disease of okra (Abelmoschus esculentus L. Moench)
    (CCSHAU, 2019) Pankaj; Vinod Kumar
    The present study entitled, “Studies on epidemiology and management of yellow vein mosaic virus disease of okra (Abelmoschus esculentus L. Moench)” was conducted during the kharif 2018 at research farm, Department of Plant Pathology, Chaudhary Charan Singh Haryana Agricultural University, Hisar. Okra yellow vein mosaic virus disease is a devastating viral disease which has a wide occurrence and causes considerable yield losses quantitatively and qualitatively. The viral disease can appear at all stages of crop growth depending upon favorable conditions. Environmental factors play important role in sustaining whitefly population and disease development. It was observed that whitefly population builds up started in month of July and reached to maximum in first week of October. The whitefly population and percent disease index (PDI) was observed maximum in first week of October due to prevailing favourable weather conditions, i.e. maximum temperature 34±2 °C minimum temperature 23±2 °C, morning relative humidity more than 90 per, wind speed about 3 km/h, more sunshine hours and no rainfall. The average whitefly population was maximum on Pusa Sawani (6.54) followed by Pusa A4 (5.27) and Varsha Uphar (3.78). All three cultivars had positive significant correlation with bright sunshine hours while morning relative humidity and maximum temperature was recorded positively non-significant. However, evening relative humidity, wind speed and rainfall was negatively (non-significant) correlated, while minimum temperature was recorded negatively significant with whitefly population. The maximum and minimum temperature, evening relative humidity, wind speed, and total rainfall were negatively correlated with OYVMV disease where morning relative humidity and bright sunshine hours were found positively correlated. The highly significant positive correlation was found between whitefly population and disease severity. The terminal PDI was observed highest in Pusa Sawani (73.00 %) cultivar and lowest in Varsha Uphar (18.75 %). The maximum PDI and disease incidence was observed in 14 July sown crop with wider row to row spacing while minimum in 15 June sown crop with closely spaced. For the management of OYVMV disease chemical, botanicals and resistance inducers were used. Amongst all foliar spray of malathion 50 EC @ 2ml/litre of water + sarpagandha leaf extract @10% was found most effective in managing the disease with PDI (15.55 %). Amongst the resistance inducers seed priming with salicylic acid @ 150 mg/litre and spray the same also found effective against OYVMV with PDI (28.89 %).