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20196
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Subject: Plant Pathology × End date: 2019 × Start date: 2019 × Type: Thesis ×
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    ThesisItemOpen Access
    Investigations on endophytic bacteria for management of downy mildew caused by Sclerospora graminicola in pearl millet
    (CCSHAU, Hisar, 2019-12) Sangwan, Pooja; Kushal Raj
    Pearl millet is a valuable staple food in semi-arid regions of the world. Pearl millet is affected by many diseases among them, downy mildew incited by oomycetes pathogen Sclerospora graminicola (Sacc.) Schroet is the most widespread and destructive disease of pearl millet. Endophytes play an important role in metabolism and physiology of the host plants. They provide multifarious benefits such as growth promotion, suppression of pathogens and nitrogen fixation. In the present study, roots and stubbles were collected from sick plot area of Bajra Pathology after the harvest of the pearl millet crop during Kharif 2016 and 2017. A total of 30 pearl millet root bacterial endophytes (PMRBE1- PMRBE 30) were retrieved from crushed roots of pearl millet streaked on Nutrient agar plates. Ten endophytic bacterial isolates were retrieved from roots of kharif 2016 crop and other twenty isolates from roots of kharif 2017 crop. All endophytic bacterial isolates were assessed for biocontrol activities. Amongst 30 pearl millet root bacterial endophytes, sixteen isolates were positive for siderophore production, three isolates viz. PMRBE6, PMRBE25 and PMRBE28 were found positive for HCN production, 30% of the bacterial endophytes showed good growth on ACC supplemented plates and cellulolytic activity was found in bacterial endophyte PMRBE18. The isolates PMRBE1, PMRBE4, PMRBE5, PMRBE6, PMRBE7 PMRBE17, PMRBE18, PMRBE20, PMRBE23 and PMRBE24 which showed maximum germination, seedling vigour index I & II and germination speed of three pearl millet cultivars HHB226, HHB67 Imp and 7042 S under in vitro conditions were selected for seed treatment as well as for foliar spray under screen house and field conditions. Amongst various pearl millet root bacterial endophytes, maximum germination, minimum downy mildew incidence at 30 and 60 DAS, better growth and yield of pearl millet cultivars were found on treatment with isolate PMRBE6, PMRBE18 and PMRBE23. On the basis of biochemical characterization and partial 16S rRNA sequencing pearl millet root bacterial endophytic isolates PMRBE6, PMRBE18 and PMRBE23 were identified as Bacillus subtilis strain PD4 (Accession no. MN400209), Serratia sp. and Alcaligenes faecalis strain HX2016003 (Accession no. MN400208). Promising root endophytes may be used for IPM of downy mildew in pearl millet after field trials.
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    ThesisItemOpen Access
    Variability, epidemiology and management of Tilletia indica Mitra, the incitant of Karnal bunt of wheat
    (CCSHAU, Hisar, 2019-11) Mamta; Rajender Singh
    Karnal bunt disease of wheat continues to be a potential threat to production and trade of wheat. The present study was planned to study cultural, morphological, molecular and pathogenic variability in Tilletia indica, epidemiology and management of this disease. On the basis of cultural and morphological characteristic, the largest teliospore size was observed in Bhiwani isolate, whereas Kapurthala isolate was having the smallest size. Different Karnal bunt isolates colony colour were white, yellowish white, creamy, creamish yellow and creamish white whereas, culture colony growth pattern of isolates were erect, compact, clustering, crustose, appressed, spreading and leathery. Maximum teliospore germination, primary sporidia formation and secondary sporidia production was recorded at 18°C in Pantnagar isolate. Best teliospore germination occurred at pH 6.0 followed by pH 5.0 Maximum coefficient of infection was expressed in HD2967 followed by DPW 621-50. Pantnagar isolate exhibited maximum mean coefficient of infection followed by Bhatinda and the least was observed in Mahendergarh isolate. Pantnagar isolate was most virulent as well as had maximum sporulation. Karnal bunt resistant reaction in three differentials namely HD 29, HD 30 and Aldan were noted. In molecular variability twelve molecular markers were tested against 10 Karnal bunt isolates and characterized into 3 major groups. Karnal bunt incidence had significant correlation with maximum temperature, rainy day and total rainfall during earhead emerging stage Two hundred seventy nine genotypes showed less than 5 coefficient of infection against Karnal bunt thereby expressing resistant reaction and 221 genotypes were susceptible having more than 5 per cent coefficient of infection under artificial inoculation condition. Maximum disease control was obtained by propiconazole 25% EC (0.1%) application, followed by combination of propiconazole 25% EC (0.05%), neem seed kernel and Trichoderma harzianum.
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    ThesisItemOpen Access
    Management of stripe rust of wheat incited by Puccinia striiformisf.sp.tritici westend
    (CCSHAU, 2019) Bilal, Mohammad; Rajender Singh
    The present study entitled, ―Management of stripe rust of wheat (Puccini striiformis f.sp.tritici westend‖ was conducted during the 2017-2018 at research farm, Department of Plant Pathology, Chaudhary Charan Singh Haryana Agricultural University, Hisar. In present study, symptoms of stripe rust appeared after 14 days with uredospores of Puccinia. striiformisf. sp. tritici(Pst). Maximum stripe rust severity was recorded in Yamunanagar followed by Ambala and least was observed in Fatehabad. The varieties HD3086, WH1105, WH1124 and WH1142 were free from stripe rust. Two commonly prevalent pathotypes were 46S119 and 110S119. Maximum terminal disease severity was recorded by WH 147 and HD2967 in seedling and tillering stage disease appearance followed by stem elongation and least disease severity was observed on milk development. Maximum yield loss was obtained by WH 147 and HD2967. WH1105. WH1124, WH 1142, WH 1237, WH 1238, WH 1241, WH 1242, WH 1244, WH 1247, WH 1248, WH 1239, WH 1246, WH 1250, WH 1251 genotypes were found resistant. Minimum disease severity observed on application of Nativo75 WG (trifloxystrobin25%WG+ tebuconazole50%), @ 300 gm/ha and Tilt 25EC (propiconazole25EC) 500ml/ha on appearance of disease at stem elongation stage and maximum yield gain was obtained. There was no residual toxicity of propiconazole25%EC (Tilt25%EC) sprayed @ 0.1% on tillering and stem elongation stage.
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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 %).
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    ThesisItemOpen Access
    Management of banded leaf and sheath blight caused by Rhizoctonia solani f.sp. sasakii of maize
    (CCSHAU, 2019) Yadav, Lokesh; Ashwani Kumar
    The present study entitled “Management of banded leaf and sheath blight caused by Rhizoctonia solani f.sp. sasakii of maize” was conducted during Kharif season of 2018 at CCSHAU, Regional Research Station Uchani, Karnal. All the laboratory work was carried out in the Department of Plant Pathology, College of Agriculture, Chaudhary Charan Singh Haryana Agricultural University, Hisar. The experiments were laid out in RBD in field and CRD in lab conditions. Maize (Zea mays L.) is the most important cereal crops in the world agricultural economy with high yield potential. The disease banded leaf and sheath blight of maize caused by Rhizoctonia solani f.sp. sasakii is considered as the main limiting factor for reduced production. The characteristic symptoms of disease appears on leaves and sheaths on 40-45 days old plants. Symptoms on leaf sheath were water-soaked, round in shape and straw-coloured whereas, on leaves irregular, water soaked, round to stretched lesions having diameter 1-3 mm were observed. In case of severe infection, the pathogen manifests itself on the cobs and results in no grain formation. It was observed that the growth of pathogen was white to creamy whitish on PDA after 24 hours of inoculation. The sclerotia were round, semi spherical to irregular in shape and were scattered in the Petri plates. To evaluate the efficacy of three different aqueous compost extracts were used under in vitro conditions for the per cent mycelial growth inhibition. It was found that the compost extracts of cow desi inhibited mycelial growth up to 22.22 per cent at 20 per cent concentration. It was revealed that seed treatment with carbendazim @ 2g/kg of seed was found most effective in controlling disease upto 54.25 per cent. Seed treatment with Trichoderma harzianum @ 0.2% and soil application with P. fluorescens @ 0.2% was most effective in controlling the disease upto 66.89 per cent and highest yield (57.68 q/ha) was also recorded from this treatment. Out of five fungicides evaluated, foliar sprays of azoxystrobin (0.1%) twice at 30 and 45 DAS was found most effective in reducing the disease upto 73.54 per cent and increasing grain yield upto 77.30 per cent. Out of twenty seven maize hybrids and sixty inbred lines of maize screened against banded leaf and sheath blight under field condition, only seven hybrids and two inbred lines showed resistant reaction against banded leaf and sheath blight disease of maize.
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    ThesisItemOpen Access
    Epidemiology and management of stem gall of coriander (Coriandrum sativum L.) caused by Protomyces macrosporus Unger
    (CCSHAU, 2019) Vijaykumar S; Kushal Raj
    The present investigation entitled "Epidemiology and management of stem gall of coriander (Coriandrum sativum L.) caused by Protomyces macrosporus Unger" was conducted in the Department of Plant Pathology, CCS HAU Hisar laboratories and research farm during year 2018-2019. Typical symptoms in infected plants were observed on all above ground parts of coriander. Symptoms appeared in the form of tumour-like swellings (galls) on stem and fruits. These tumours were smooth initially but later ruptured and turned to be rough. The pathogen Protomyces macrosporus was isolated as pure culture on PDA medium enriched with yeast extract (PDA+YE). The colony colour was creamy white and chlamydopsores were yellowish brown and spherical in shape with three distinct layers & diameter 40-80 μm. The pathogenicity was confirmed as the symptoms developed after 63 and 75 days of incubation with the application of two different source of inoculum. Epidemiology of pathogen was studied under field condition by sowing the crop at five different dates and disease severity on tagged plants and over all incidence was maximum in December 1st week sown crop with average temperature of 28.9°C and 80 per cent of relative humidity. Out of five fungicides evaluated against Protomyces macrosporus, Ridomil MZ and Blitox 50 WP were found most effective and significantly superior among the treatments with 100 per cent growth inhibition of the pathogen at 0.2 per cent concentration under in vitro conditions. Out of five plant extracts evaluated under in vitro conditions against the pathogen, datura extract at 10 per cent was found most effective in mycelial growth inhibition. Among three bioagents evaluated under in vitro conditions against the pathogen, Pseduomanas fluorescens was found most effective to inhibit the growth of pathogen. Seed treatment and foliar spray of Ridomil MZ and Blitox 50 WP at 0.2 per cent was found most effective to manage the disease severity and incidence, resulting in comparative higher yield under field conditions. Amongst 28 genotypes screened against stem gall of coriander, one genotype viz., ICS-4 was found resistant, eleven genotypes as moderately resistant and sixteen genotypes were moderately susceptible.