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Subject: Agricultural Microbiology × Thesis Type: M.Sc ×
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Now showing 1 - 9 of 148
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    ThesisItemOpen Access
    Isolation and Characterization of Spore Associated Bacteria (SAB) From Rhizophagus irregularis and their Effect on Micropropagatedsugarcane Plantlets
    (University of Agricultural Sciences, Dharwad, 2018-09) Ajay, A.N.; Nirmalnath, P. Jones
    An investigation was carried out to isolate spore associated bacteria (SAB) of Rhizophagus irregularis. Out of twenty two SAB isolates, five were selected based on their ability to influence the mycorrhizal parameters like sporulation and percent root colonization. Selected SAB isolates were characterized and tested for their functional traits such as production of indole acetic acid, gibberlic acid, cytokinin, siderophore, P-solubilisation, ACC deaminase and antagonistic activity against Colletotrichum sp. Results revealed that all the selected SAB isolates were positive for IAA, cytokinin and GA ranging from 10.27 to 17.04 µg /ml of culture filtrate; 0.53 to 3.87 µg /ml of culture filtrate and 3.40 to 8.24 µg /25ml of culture filtrate respectively. All the selected SAB isolates showed positive for ACC deaminase activity, two isolates possessed mineral phosphate solubilization activity and four isolates were found to be antagonistic against Colletotrichum sp. Nursery studies have indicated that the dual inoculation of Rhizophagus irregularis and SAB consortium significantly increased relative chlorophyll content, plant growth under and improved survivability of micropropagated sugarcane plantlets. Results of the field experiments have revealed that the precolonised seedlings with AMF and SAB recorded the highest plant height, relative chlorophyll content, enzymatic activity, mycorrhizal parameters, biophysical parameters and P content over uninoculated control. The SAB isolates were authenticated by amplifying 16S rRNA gene sequence. The blast results have clearly indicated that the SABNA2, SABNA9, SABNG12, SABNG14 and SABLG19 were very close to uncultured Bacillus sp., Burkholderia lata, Sphingomonas sp., Mesorhizobium amorphae and Klebsiella pneumonia respectively.
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    ThesisItemOpen Access
    Astaxanthin Recovery and Effect of Protein Hydrolysates on Chilli Seedlings, Derived From the Lactic Acid Bacterial Fermentation of Shrimp Waste
    (University of Agricultural Sciences, Dharwad, 2018-09) Bhavi, Ravikiran K.; Jagadeesh, K.S.
    An investigation was carried out to isolate and screen lactic acid bacteria (LAB) from shrimp for their proteolytic activity and further, these proteolytic LAB isolates were used for the extraction of astaxanthin from shrimp waste through fermentation processes. The protein hydrolysates obtained as a by-product was sprayed to chilli seedlings raised in pro-trays in order to record its influence on growth promotional and physiological activities. The experimented was conducted at Dept. of Agril. Microbiology, College of Agriculture, University of Agricultural Sciences, Dharwad. Of the 27 LAB isolates, five best selected were used for astaxanthin extraction based on their proteolytic activity. The reference strain for proteolytic activity, Bacillus sp. (MTCC-1747), was collected from Institute of Microbial Technology (IMTECH), Chandigarh. Among the isolates, LABS-06 yielded the maximum quantity (6.01 µg/ g) of astaxanthin from shrimp waste. Further, the isolate LABS-06 yielded 9.05 µg/ g of astaxanthin after optimizing the fermentation parameters viz., 72 hours of incubation with a glucose concentration of 10 g l-1 at 30 °C. Fermented products of isolate LABS-06 showed the highest bio-chemical and microbiological composition compared to control. The greenhouse studies indicated that spraying of protein hydrolysates (obtained from fermentation of shrimp waste with LABS-06) at 15 DAS with 0.5 per cent (among 0.5, 0.75 and 1.0 %) recorded highest for growth parameters like root length, shoot length, relative chlorophyll content and dry matter content at 30 and 45 DAS. The present study has indicated that the proteolytic native LABS-06 can be used in the extraction of astaxanthin from shrimp waste and also the protein hydrolysates which is a by-product can be used as a bio-stimulant to enhance the growth of chilli seedlings.
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    ThesisItemOpen Access
    Isolation, Screening and Evaluation of Native Am Fungi for Mitigating Moisture Stress in Soybean [Glycine max (L.) Merill]
    (University of Agricultural Sciences, Dharwad, 2018-08) Konnur, Suma R.; Nirmalnath, P. Jones
    An investigation was carried out to isolate native AM fungal isolates from the rhizosphere soil of soybean growing areas of Belagavi and Dharwad districts. Further, the forty native AM fungal isolates were screened based on their peroxidase activity and total dry matter accumulation in soybean plant under the restricted water regime of -500 kPa. These experiments were conducted at Weed Control Scheme, MARS and Department of Agricultural Microbiology, University of Agricultural Sciences, Dharwad. A pot culture experiment was laid out in completely randomized design with factorial concept with three irrigation regimes viz., -33 kPa, -500 kPa and -1000 kPa. Moisture was maintained by adding water based on daily evapotraspiration rate. The results of the pot culture studies have revealed that UASDAMFsoybean consortium and UASDAMF consortium significantly increased the stomatal conductance, photosynthetic activity, transpiration rate, PALase activity, ACC deaminase activity, leghaemoglobin content, spore count and per cent root colonization over uninoculated control. Further, UASDAMF consortium and UASDAMFsoybean consortium reduced the leaf temperature, proline (4.94 and 5.35 µmol g-1 FW), glycine betaine content (4.44 and 5.09 µmol g-1 FW), peroxidase activity (3.79 and 4.05 U mg-1 protein) in the plants compared to single inoculants and UIC. The present study has indicated that UASDAMFsoybean consortium and UASDAMF consortium are quite promising in mitigating moisture stress under pot culture studies and also these were found to be efficient in increasing the growth parameters, biomass and nutrient status of soybean plants. Thus, our preliminary findings are indicative of the effectiveness of AMF in protecting plants from water stress and hence can be a promising strategy to develop a biological tool for mitigation of moisture stress.
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    ThesisItemOpen Access
    Protein Hydrolysates of Soy Meal through Bacterial Hydrolysis and their Effect on Growth and Yield of Cowpea (Vigna unguiculata L.)
    (University of Agricultural Sciences, Dharwad, 2018-08) Dalawai, Laxmi S.; Jagadeesh, K.S.
    In-vitro studies were conducted to isolate protease producing bacteria at the Department of Agricultural Microbiology, University of Agricultural Sciences, Dharawad during 2017-18. As many as 68 proteolytic bacterial isolates were isolated from different sources viz., soybean rhizospshere, rotten green peas and soil enriched with glyricidia and subabul using soy meal agar medium. Ten promising isolates were selected based on enzyme potency and PPB-3 was the most efficient isolate in terms of enzyme activity. Soy meal was fermented with PPB-3 under optimized conditions and found to posses higher nutritional, phytochemical and microbiological composition when compared with other treatments. Cowpea germination percentage and seedling vigour index were significantly increased due to priming of seeds with soy meal protein hydrolysate @ 10 per cent (108 and 141.86 % respectively) compared to control. Effect of spraying soy meal protein hydrolysate at different concentrations on cowpea was carried. Out of four concentrations, spraying twice @ 10 ml L-1 resulted in increased growth of plant and higher relative chlorophyll content. The treatment also significantly increased microbial population both in the rhizosphere and phyllosphere with a concomitant increase in the soil enzyme activities such as dehydrogenase, urease and phosphatase. Spraying cowpea seedling with soy meal protein hydrolysate significantly increased pod and grain yield. The highest pod yield (8.44 g plant-1) and grain yield (12.23 g plant-1) were obtained by spraying soy meal protein hydrolysate twice @ 10 ml L-1. The present investigation clearly brought out the potential of soy meal protein hydrolysate in stimulating rhizosphere and phyllosphere microbiological population and their activities in terms of soil enzymes eventually improving growth and yield of cowpea.
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    ThesisItemOpen Access
    Effect of Actinobacteria on the Growth and Manifestation of Biotic Stress in Chilli (Capsicum annuum L.)
    (University of Agricultural Sciences, Dharwad, 2018-07) Jagadeesh, E.M.; Krishnaraj, P.U.
    ABSTRACT Actinobacteria are Gram positive, filamentous, sporulating, heterotrophic prokaryotic bacteria. They are known for degradation of organic materials, production of plant growth promoting substances and reduction in the population of pest and disease. Hence, the present study was conducted to isolate actinobacteria, test their multifunctional activities and performance on the growth and manifestation of biotic stress in chilli crop under pot culture at the Department of Agricultural Microbiology, University of Agricultural Sciences, Dharwad, Karnataka during 2017-2018. Soil samples collected from different locations were subjected to the isolation of actinobacteria by standard dilution and plating on Starch Casein Agar (SCA). A total of 52 isolates were purified and used to understand the influence on the growth parameters of chilli. Out of 52, five actinobacterial isolates were selected based on their positive influence on germination percentage, seedling vigour index, shoot length, root length, fresh weight and dry weight of seedlings. The selected five isolates exhibited multifunctional activities such as IAA production, GA production, antagonistic activity against fungal pathogens and reduction of biotic stress. The five efficient actinobacterial isolates along with five reference isolates were also employed to study their influence on the growth parameters, population of sucking pests (thrips, mites, aphids and whiteflies), disease (murda complex) and yield parameters of chilli plants under greenhouse conditions. Streptomyces shandonggensis AUDT 217 was the most promising isolate followed by AUDT 811 in terms of production of plant growth promoting substances, antagonistic activity against fungal pathogens (Sclerotium rolfsii and Colletotricum capsici), growth parameters, soil enzymatic activities, nutrient content, uptake and alleviation of sucking pests (thrips, mites, aphids and whiteflies) and disease (murda complex) in chilli.
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    ThesisItemOpen Access
    Effect of Inoculation of Microbial Consortia on Growth, Yield and Nutrient Uptake of Green Gram (Vigna radiata L.)
    (University of Agricultural Sciences, Dharwad, 2018-06) Badiger, Narayan M.; Jagadeesh, K.S.
    Field evaluation of microbial consortia developed in the Department of Agricultural Microbiology, College of Agriculture, University of Agricultural Sciences, Dharwad was done in green gram crop in field of MULLaRP scheme during kharif 2017. The microbial consortia included Gluconoacetobacter sp., Azospirillum sp. (ACD 15), P-solubilizing bacteria (Pseudomonas striata), K-solubilizing bacteria (KSB-27), Zn-solubilizing bacteria (ZnSB), plant growth promoting rhizobacteria (JK-16), pink pigmented facultative methylotrophs (PPFM-33 and PPFM-58), lactic acid bacteria (LAB 82, LAB-75 and LAB LS-36), Si-solubilizing bacteria (SiSB) and actinomycetes strains (AUDT-502, AUDT-248, A-34, PSA-5, PSA-7 and UPM-34) with 100 per cent and 75 per cent recommended dose of fertilizers. The consortia were inoculated to green gram by seed treatment (4 ml kg-1 seed), soil application (2.5 l acre-1 with 250 kg vermicompost) and as foliar spray (4 %). The consortia inoculated treatment along with 50 per cent recommended fertilizer dose showed significantly highest plant height (63.75 cm plant-1), number of leaves (32.67 plant-1), nodulation (58.49) and nodules dry weight (1.17 g plant-1) and also highest nutrient content and its uptake as compared to uninoculated control (Package of practices only). The treatment with 50 per cent NPS along with microbial consortia recorded highest number of pods (29.75 plant-1), total dry matter (15.84 g plant-1) and grain yield (16.68 q ha-1) as compared to full dose of recommended chemical fertilizers and also higher B: C ratio (3.28) was noticed in this treatment. The present investigation has come out with the result that inoculation of selected microbial consortia enhanced the growth, yield, soil health and nutrient uptake by green gram. I recommend application of rhizosphere consortia-2 (Gluconoacetobacter sp., Pseudomonas striata), KSB-27, ZnSB, plant growth promoting rhizobacteria (JK-16), PPFM-33 and LAB-75) which could reduce 50 per cent of recommended NPS (nitrogen, phosphorous and sulphur) fertilizers thereby reducing input cost on chemical fertilizers.
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    ThesisItemOpen Access
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    ThesisItemOpen Access
    Influence of P-Solubilizing Fungal Isolates on Growth, Nutrient Uptake and Biomass of Soybean (Glycine max L. Merill.)
    (University of Agricultural Sciences, Dharwad, 2017-07) Prem Kumar T. M.; Savalgi, V.P.
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    ThesisItemOpen Access
    Effect of Mycorrhization in the Management of Striga in Sugarcane Under Field Conditions
    (University of Agricultural Science, Dharwad, 2016-09) Manjunatha H.P.; P. Jones Nirmalnath