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20205
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Subject: Plant Pathology × End date: 2020 × Start date: 2020 × Type: Thesis × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    Studies on isolation, identification, characterization and evaluation of potential rhizobacterial isolates against Rhizoctonia solani Kühn of soybean
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2020-11) Idong, Stanzin; Sharma, Manju
    A total of thirty-one rhizobacterial isolates obtained from maize and soybean rhizospheric soil samples from various location of Pantnagar on two different media Kings B and Nutrient agar media were culturally identified and evaluated for their antagonistic potential against Rhizoctonia solani of soybean. The cultural characteristics included colony colour, shape, size, margin, surface and elevation. Seven isolates which inhibited growth of Rhizoctonia solani with highest being recorded with isolate MR3 (82.05%) followed by SR1 (68.28%), SRP3 (59.82%) , SRP4 (51.28%) , SRP1 (49.56%) , SR2 (48.72%) and SRP2 (40.18%) were morphologically, biochemically and functionally characterized. The morphological test clearly revealed that only two were gram positive and rest were gram negative. Biochemical test includes Catalse test, Oxidase test, Urease test, Starch hydrolysis test, Gelatin liquefaction, Cellulase test, Methyl red test and Citrate utilization test. On the basis of morphological and biochemical characterization it can be presumed that isolates SR1 and MR3 were related and other isolates SRP2, SR2, SRP3, SRP1 and SRP4 were more related. Screening for their functionality showed that 6 of the isolates produced nitrogen fixation, 3 exhibited phosphorus solubilization with SRP 4 showing highest solubilization index (2.50), 6 potassium solubilization with SRP 3 showing highest solubilization index (2.91), 3 exhibited siderophore production, 2 known for IAA production and 6 showed Ammonia production property. On the basis of functional and antagonistic evaluation four isolates were selected SR1, SRP3, SRP4 and MR3. The compatibility among the rhizobacterial isolates and with Trichoderma isolates (PT-6, PT-10, DDNT-4) were screened. Isolate SRP4 was compatible with all other isolates and isolate SRP3 was compatible with all Trichoderma isolates. Bacterization with potential isolates offered protection against aerial blight under controlled glass house condition with maximum growth inhibition by SRP 4 (55.00%). The potential isolates were further evaluated for their growth promotion activity and induction of defence related enzymes. The results obtained indicated that isolate SRP 4 bacterized plant showed highest shoot length (43.65 cm), root length (10.57 cm), fresh shoot weight (2.20 g) and fresh root weight (0.34 g) and chlorophyll content ( chl a-1.91mg/g FW, chl b-0.94 mg/g FW, total chl-2.85mg/g FW). Treatments that were bacterized and challenged with pathogen showed higher accumulation of POD (132.24 nmol/min/mg protein), SOD (10.27 unit/mg protein/min), Chitinase (140.56 μg glucose/min/mg protein) and β-1,3-glucanase (320.63 μg glucose/min/mg protein) as compared to only bacterized plants. While the absolute control depicted the lowest accumulation of PR proteins. Treatment SRP4 showed highest production of protein, Chitinase, β-1,3-Glucanase, POD and SOD. Overall isolate SRP4 is one such isolate that proved outstanding for suppressing aerial blight of soybean and having PGP traits also.
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    ThesisItemOpen Access
    Compatibility of agrochemicals recommended for rice cultivation in relation to management of rice pathogens
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2020-12) Singh, Vivek; Bijendra Kumar
    Rice (Oryzae sativa L.) is the primary source of food cultivated all around the world. The crop is infected by numerous insects-pests and diseases which cause huge loss in the yield and to reduce these losses farmers apply cocktails of agrochemicals without knowing about the compatibility between the agrochemicals. The present investigation was envisaged to test the compatibility and fungitoxicity between agrochemicals recommended by CIB at particular growth stage against Fusarium fujikuroi, Rhizoctonia solani, Cochliobolus miyabeanus and Xanthomonas oryzae pv. oryzae attacking at vegetative, tillering and panicle emergence stage. The different combinations of insecticides, fungicides, growth regulator and fertilizer were evaluated using poisoned food technique and spectrophotometry in vitro with the objective to reduce the cost involved in separate foliar application of these agrochemicals. During the vegetative phase 34 combinations of 8 agrochemicals were evaluated where mancozeb and isoprothiolane were compatible with all the combinations however, carbendazim was found to be compatible with most of the agrochemicals except chlorpyriphos, chlorantraniliprole and chlorantraniliprole + urea. Interestingly, the addition of urea with the fungicides increased the fungitoxicity against F. fujikuroi urea increasing the fungitoxicity of all the fungicides in the combinations. Most of the combinations were safe except carbendazim + chlorantraniliprole + urea. Of the 62 combinations of 10 agrochemicals evaluated against R. solani and C. miyabeanus attacking during the tillering stage. Carbendazim alone and in combination with other agrochemicals except acetamiprid + urea and thiamethoxam + urea was found to be superior in controlling R solani however, the combination of propineb + carbendazim was found to show synergistic effect against C. miyabeanus with carbendazim showing compatibility in all the combinations except acetamiprid + urea and thiamethoxam + urea. The combination of streptomycin + propineb was found to be highly compatible among the 6 combination against C. miyabeanus during panicle Initiation stage and streptomycin + copper hydroxide, streptomycin + tricyclazole were found to be equally effective and compatible against Xanthomonas oryzae p.v. oryzae. Most of the combinations were safe to use with enhancencement of the fungitoxicity with addition of urea. However, the insecticidal property of these combinations and their efficacy under fields is unknown so evaluation of these properties should be done before recommending them to the farmers.
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    ThesisItemOpen Access
    Study on different strains of Hericium erinaceus (Bull. : Fr) Pers. for their qualitative & quantitative traits
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2020-08) Sh.Sholyavei; Mishra, S.K.
    Hericium erinaceus (Bull. : Fr.) Pers. is an edible and medicinal mushroom is very popular in traditional Eastern Medicine and has been used to treat different human illness and known for strengthening the immune system and neurological health of mankind. For this reason, it has received considerable attention worldwide. Hericium erinaceus is a toothed fungus characterized with long spiny hymenophore that makes it a white snowball shape. Present research work was started with the objectives of evaluating strains (He-101, He-102, He-104, He-105, He-107, He-108, and He-109) of Hericium erinaceus and substrates (wheat straw/ poplar sawdust) along with In vitro study of mycelium growth of the best-selected strain(s) in different media, temperature, and pH. Morphological characterization of the strains was also done. The strain He-108 completed spawn run within 24 and 26 days on growing media 1 and 2, respectively. However, He-101 and 104 harvested early from growing medium 1 within 42 and 43 days after spawning. It was invariably found that among all strains, He- 104 demonstrated the highest 205.7 g yield /1.5 kg growing medium 1 (31.65% biological efficiency) at 15-20oC temperature with an average 10.70 numbers of mushroom. This yield was achieved from maximum number of 5 harvestings of total cropping period of 101 days. The performance of growing medium 1 was found superior than to that of growing medium 2.The average biological efficiency of 17.66 % with the total number of 7.26 fruits were recorded with growing medium 1 than to that of an average 3.21% BE and 1.98 total number of fruits obtained from growing medium 2. As a result, the strain He-104 showed maximum 89.56 mm diametric growth in vitro on PDA of pH 5 at 25° temperature. A morphological study of the above strains was also done using a mature fruit body. The fruits of He-101, He-104, He-107, He-108, He-109 were categorized into clump type. He-105 had thick branching type sporophores and He-102 was known with diffuse branching type sporophores. Microscopic study for the dimension of basidia and spore showed that they were ranged from 27- 45 X 5.20-7.51 μm and 5.20- 6.90 X 4.20-5.80 μm in the size, respectively.
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    ThesisItemOpen Access
    Evaluation of consortium of potential fungal and bacterial biocontrol agents for the management of sheath blight of rice
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2020-10) Sapna; Sharma, Roopali
    Rice is one of the important and staple food crop for 70% of world population. India shares about 21% of global rice production. Sheath blight of rice caused by Rhizoctonia solani causes heavy losses ranges between 4-50%. To overcome the problem different management strategies are applied. Among all strategies chemical control still performs better in disease reduction although, due to indiscriminate use of fungicides it upset the biodiversity, environment and soil health. The biological control has emerged as an effective approach for reduction of rice sheath blight because BCA’s have property of growth promotion, induced systemic resistance, hyperparasitism against the Rhizoctonia solani. Due to the inefficiency of working of biocontrol agents in adverse environment and different mode of action of biocontrol agents in one formulation, the present investigation has carried out to study the combining effect of fungal and bacterial biocontrol agents consortium for reduction of rice sheath blight disease as well as for growth promotion of rice plant. During the investigation 11 treatments were used, Two are the potential Trichoderma asperellum isolates (Th17, Th14), two potential Pseudomonas fluorescens isolates (Psf173, Psf2), four are the consortium of potential Trichoderma asperellum and Pseudomonas fluorescens isolates (Th17+Psf173, Th17+Psf2, Th14+Psf2, Th14+Th17), one is standard check PBAT3 (Th14+Psf173), one is fungicide carbendazim and one is control (which is untreated). The pathogen Rhizoctonia solani was identified from collected diseased samples by means or morphological and cultural characteristics. Formation of sclerotia and mycelium in Petri Plates and right angle (90º) branching under microscope proved that the pathogen is Rhizoctonia solani. In case of glass house experiment seed treatment, soil treatment and foliar sprays of biocontrol agents consortium on seed germination percentage, root-shoot length, dry weight and fresh weight of rice plant reveals that the consortium PBAT3, followed by consortium of TH17+Psf173 found be effective as comparison to the carbendazim and control. In field condition, seed treatment, soil treatment, seedling treatment and foliar sprays of biocontrol agents consortium shows that the consortium were found effective in every aspect. Such as plant length, tillers/hill, yield q/ha and test weight was found maximum in consortium of PBAT3 followed by consortium of TH17+Psf173 which was far better than carbendazim and control. Experiment in field condition also reveal that the minimum disease severity were found in carbendazim followed by PBAT3 but overall results shows that the consortium is almost effective as carbendazim in sheath blight disease reduction. Beside this, the biocontrol agents are most effective when applied from initial stages of crop growth and the investigation also proved that the seed treatment, soil treatment and foliar spray of biocontrol agents consortium showed the best results in disease reduction percentage as well as in yield attributes. Therefore, it can be recommended that PBAT3 and Th17+Psf173 consortium against sheath blight disease can be practiced in farmer’s field successfully.
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    ThesisItemOpen Access
    Management of aerial blight of soybean (Rhizoctonia solani Kühn) through resistant sources, fungicides and chitosan nanoparticles
    (G.B. Pant University of Agriculture and Technology, Pantnagar - 263145 (Uttarakhand), 2020-02) Arya, Chandra; Singh, K.P.
    Soybean (Glycin max L. Merril) is one of the most important seed legumes, which contributes 25 % of the global edible oil and about two- third of the world’s protein. Among the major diseases infecting soybean crop, aerial blight caused by the fungus Rhizoctonia solani Kuhn is most destructive and leads to huge yield losses every year around the world. The disease produces dark brown irregular spots on leaves and plant parts making the plant unproductive. Use of resistant varieties is an effective strategy for management of the disease. Sixteen soybean varieties were screened against aerial blight for two years viz., Kharif 2017 and 2018. It was observed that disease pressure was high during 2017 as compared to 2018. In 2017, the varieties PS-1572, PS-1583 and PS-1518 were found to be resistant against RAB whereas in 2018, the varieties showing resistant reaction were PS-1518, PS-1556, PS-1572 and PS-1583. Out of the 16 varieties screened against RAB, four varieties viz., PS-1518, PS-1572, PS -1556 and PS-1583 were found to be resistant in the pooled data while six varieties viz, PS1546, PK-262, PK-472, NRC-7, PS-1029 and PS-1092 exhibited a moderately resistant reaction to RAB. The effect of five different growth media against Rhizoctonia solani was also studied. Out of the five media used in the study, Czapek’s dox agar media was found best for mycelial growth and development and Corn meal agar was found best for the sclerotia production. Five new generation fungicides were also tested in vitro against the fungus, out of which, Nativo 75% WG (tebuconazole 50% + trifloxystrobin 25%) was found to be the most effective with 100 percent growth inhibition at 5 ppm and above concentrations. The effect of chitosan nanoparticles (CNPs) on the growth of R. solani was also tested. The most effective concentration of CNPs was 1 ppm which gave 67.77 percent growth inhibition of the fungus. The effect of chitosan nanoparticles on growth parameters of soybean was also studied. It was observed that 100 ppm concentration of CNPs gave 100 percent germination in case of JS-335 and 99.33 per cent in case of PS-1024 as compared to control with 90 an 80 per cent germination, respectively. The germination percentage was 99.33 and 88.67 and 97.33 and 70.00 per cent at 75 and 50 ppm concentration in JS335 and PS1024 respectively. Energy of emergence and germination index found to be highly effective at 100 ppm in PS- 1024 and JS-335. But the mean germination time was found lowest with 5.07 days in JS-335 as compared to control. The 50 ppm concentration of CNPs gave the highest mean germination time with 5.25 and 5.24 days in PS-1024 and JS 335, respectively. Treatment with chitosan nanoparticles was found to increase the root/shoot ratio and vigour index at a concentration of 100 ppm. Effect of chitosan nanoparticles on the fungal mycelium was studied using scanning electron microscopy and it was observed that in control, the mycelia were septate and uniformly branched with prominent constrictions at the branching point while in the treated plate, the mycelium was observed to be distorted with irregular septation or complete absence of septa, change in cell permeability, loss off cell turgidity, with a collapsed cell wall which was intermixed to form a clump of unevenly distributed cytoplasm.