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Sri Karan Narendra Agriculture University, Jobner

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Subject: Plant Pathology × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Biochemical changes in fenugreek due to powdery mildew (Erysiphe polygoni DC.) and its management
    (2022) B.R, Rachanashree; Kumawat,G.L.
    Fenugreek (Trigonella foenum-graecum L.) is one of the important and oldest spice and medicinal crops and is cultivated throughout India. It is attacked by many diseases, however, powdery mildew incited by Erysiphe polygoni DC. is a major constraint in cultivation of fenugreek. Powdery mildew disease appeared during the end of January and persisted till the maturity of the crop. Symptoms were observed as white floury patches on leaves, tendrils, stem and pods whereas cleistothecia appeared late in the season seen as black specks immersed in mycelial mat. Microscopic observation revealed that conidia were barrel in shape and formed singly and in chains. Conidiophores were septate that were straight to sub-straight with 4 to 5 cells. Thirty six genotypes and varieties were screened under natural condition to find out the source of resistance against the disease. It was found that HM 444 and UM 411 showed resistant reaction with percent disease intensity (PDI) of 9.66 and 10.27 respectively. The remaining nine were rated as moderately resistant, thirteen as moderately susceptible and twelve as susceptible.Biochemical studies on thirty six genotypes and varieties were undertaken twice, once before the disease occurrence and then after the disease occurrence. It was found that total phenol, peroxidase (PO) and polyphenol oxidase (PPO) content in plants increased in all the genotypes after the disease appearance and the amount of these components were higher in resistant ones and comparatively lower in susceptible ones. Chlorophyll content of all the lines decreased after the disease appearance and was greater in resistant lines than susceptible lines. Correlation between biochemical components and percent disease intensity was worked out. Phenol showed negative significant correlation (- 0.958) (-0.864) in both healthy and infected leaves with PDI, the enzyme peroxidase showed negative significant correlation (-0.929) (-0.847) in both healthy and infected leaves with PDI, the enzyme PPO showed negative significant correlation (-0.892) (-0.837) in both healthy and infected leaves with PDI and chlorophyll also showed negative significant correlation (-0.758) (-0.892) with PDI. Six treatments were evaluated along with one untreated control in three replications. Among them, two sprays of panchgavya 5% recorded minimum percent disease intensity of 30.66 with yield 13.47 q/ha. Field evaluation of six systemic acquired resistance elicitors with one unsprayed control in three replications were undertaken. The crop was sprayed at 45 days after sowing and it was found that salicylic acid 200 ppm resulted in minimum percent disease intensity of 21.18 and yield of 16.07 q/ha. Six fungicides with one treatment of water spray and untreated control in three replications were carried out twice where hexaconazole 5% SC at 0.1% recorded minimum percent disease intensity of 11.63 and with higher yield of 20.65 q/ha. ICBR for fungicides were calculated and hexaconazole showed maximum ratio of 1: 37.91
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    ThesisItemOpen Access
    Biochemical Changes in Pea Due to Powdery Mildew Incited by Erysiphe polygoni DC and its Management
    (2022) MEENA, DINESH KUMAR; Singh, Jitendra
    Pea (Pisum sativum L.) is an important cool season crop, belongs to the Leguminosae family. Pulses are providing quality food to teeming million and restoring soil fertility through nitrogen fixation. Pea crop is damaged by many fungal, viral and bacterial diseases. Powdery mildew of pea incited by Erysiphe polygoni emerged as a major disease in Rajasthan. Generally, this disease appeared in the first week of March and reaches at peak in April. Powdery mildew of pea is detected by presence of white floury patches appearing on upper and lower sides of the leaves as well as pods, stem, tendril etc. in extreme condition it causes significant losses in quantity and quality of the seed. In vitro studies showed that the highest conidial germination was reported at 250C temperature and 80 per cent relative humidity. Among biochemical basis of resistance in pea, peroxidase and phenol content are minimum in healthy plants compared to infected plants. Reducing sugar is maximum in healthy plants as compared to infected plants. Among tested six natural products used as two foliar applications; Neem Seed Kernel Extract (NSKE) was found most effective with 62.38 per cent disease control. Followed by Panchgavya with 57.50 per cent disease control. Among tested five SAR activators single spray of salicylic acid @250ppm before disease appearance recorded minimum 25.71 per cent disease intensity by decreasing 55.07 per cent disease intensity over control. Out of six fungicides tested for their efficacy for the control of Erysiphe polygoni on pea. Two foliar spray of Hexaconazole @0.1% first at before disease appearance and second at after disease appearance were found minimum 13.85 per cent disease intensity by decreasing 76.55 per cent disease intensity over control followed by Propiconazole was second best recorded with 16.68 per cent disease intensity by decreasing 71.76 per cent disease intensity over control.
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    ThesisItemOpen Access
    Management of Alternaria leaf spot of coriander incited by Alternaria alternat
    (2022) KANSOTIA, KAVITA; Meena, A.K.
    Coriander (Coriandrum sativum L.) is an important seed spice crop of India specially growing in Rajasthan. The crop suffers from several disease among those leaf spot is emerging as a major problem in coriander cultivation. Leaf spot infected leaves of coriander were collected from farmer’s field. Pathogen was isolated, purified and identified as Alternaria alternata and its pathogenicity was proved. Four bio-agents were evaluated against Alternaria alternata by dual culture technique. Among all the tested bio-agents Trichoderma harzianum was found best which inhibit maximum mycelial growth (74.44%) of fungus. When bio-agents were used as seed treatment and soil application under field conditions, Trichoderma harzianum was found most effective and resulted in significant reduction in disease intensity (38.30%) as compared to untreated control. The leave extract of five plant species were evaluated at two concentrations (5% and 10%) against Alternaria alternata by Poisoned Food Technique. The leave extract of neem (88.88% at 10% and 83.33% at 5%) followed by garlic were found most promising in inhibiting mycelial growth at both concentrations. When plant leave extracts tested as foliar application under field conditions, neem was found most effective with maximum disease control (50.94 at 10%) followed by garlic leave extract. Biochemical studies on coriander leaf spot disease induced by A. alternata was carried out. Significant increase in phenol and peroxidase (PO) was found in infected plants as compared to healthy plants. A reduction in sugar content was also observed with the increase in disease severity. * A Post Graduate Student, Department of Plant Pathology, S.K.N. College of Agriculture, Jo
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    ThesisItemOpen Access
    Interaction of Fusarium solani and Meloidogyne javanica in Causing Root Rot of Fennel and its Managemen
    (2022) KUMAWAT, KIRAN; Goyal, S.K.
    Fennel is one of the important seed spice crops grown in India Fusarium solani and Meloidogyne javanica are widely distributed pathogens in India which cause root rot and root knot complex in fennel and responsible for severe economic losses. Considering the economic importance of these, the present investigation was carried out to know the interaction of Fusarium solani and Meloidogyne javanica in causing root rot of fennel and its management. Fennel plants depicting root rot symptoms were collected from farmer’s field. The fungus, Fusarium solni was isolated from infected fennel plants, purified by single spore technique and proved pathogenic. An experiment was conducted on interactive effect of Fusarium solani and Meloidogyne javanica on root rot incidence in fennel. Minimum nematode reproduction and maximum plant growth parameters were recorded by inoculating fungus at the time of sowing and nematode after one week. While, maximum disease incidence was recorded by inoculating nematode at the time of sowing and fungus one week after. Among screened 30 varieties/germplasm of fennel, four varieties (RF-101, RF-145, RF-157 and RF-143) showed resistant reaction, 21 showed moderately resistant reaction and five showed susceptible reaction against the pathogens. Among all varieties/germplasm, highest root rot incidence was recorded in RF-125 and UF-33. However, minimum root rot incidence was recorded in RF-101 and RF 205. An experiment was conducted on management of the root rot and root knot disease complex through bio-agents (@ 2.5kg/ha as soil application) and botanicals (@ 10% concentration as seed soaking). Among all the treatments, combination of Trichoderma harzianum and garlic showed best results followed by Trichoderma harzianum + parthenium for increase plant growth parameters and reduce percent root rot incidence as well as nematode reproduction as compared to untreated control. Biochemical studies were also carried out to find the peroxidase, polyphenol oxidase, phenylalanine ammonia lyase and phenol level. Highest peroxidase, polyphenol oxidase, phenylalanine ammonia lyase and phenol activities was observed in Trichoderma harzianum and garlic followed Trichoderma harzianum + parthenium and parthenium treated fennel roots as compared to untreated control
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    ThesisItemOpen Access
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    ThesisItemOpen Access