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2013 - 201722
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Subject: Agricultural Microbiology × End date: 2017 × Start date: 2012 × Thesis Type: M.Sc ×
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Now showing 1 - 9 of 22
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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
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    ThesisItemOpen Access
    Isolation and Screening of Arbuscular Mycorrhizal Fungi for Suppression of Orobanche sp., a Parasitic Weed in Tobacco (Nicotiana tabacum L.)
    (University of Agricultural Science, Dharwad, 2017-10) Chandrashekharagowda B.; Jones Nirmalnath, P.
    An investigation was carried out to isolate native arbuscular mycorrhizal fungal (AMF) isolates from the Orobanche suppressive soils of tobacco growing areas of Nippani in Belagavi district, in order to screen them for their ability to suppress obnoxious weed Orobanche as well as to promote plant growth under pot culture studies. These experiments were conducted at the Weed Control Scheme, Main Agriculture Research Station and Department of Agricultural Microbiology, University of Agricultural Sciences, Dharwad from 2014-16. The results of the pot experiment revealed that the native AMF isolates UASDAMFT5 (Glomus fasciculatum), UASDAMFT2 (Glomus radiata), UASDAMFT6 (Glomus deserticola), UASDAMFT3 (Glomus mosseae), AMF consortium (standard) and UASDAMFT consortium (tobacco native) suppressed the Orobanche parameters and plant growth parameters of tobacco over uninoculated plants in the presence of Orobanche. Inoculation of AMF isolates significantly improved the spore count over the uninoculated plants. The maximum spore count was recorded in AMF consortium (standard) (621 spores per 50 g), UASDAMFAMFT consortium (tobacco native) (619 spores per 50 g) and native isolates viz., UASDAMFT5, UASDAMFT2, UASDAMFT6 and UASDAMFT3 (277, 268, 267 and 265 spores per 50 g respectively ) over the uninoculated control (45 spores per 50 g). The present study has indicated that UASDAMFT5, UASDAMFT2, UASDAMFT6 and UASDAMFT3 isolates are quite promising in inhibiting Orobanche seed germination similar to AMF consortium (standard) and UASDAMFT consortium (tobacco native) under pot culture studies. Thus, it can be concluded that UASDAMFT5 and UASDAMFT2 isolates can suppress the Orobanche seed germination efficiently and these can be used as a biotic tool in the Orobanche management.
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    ThesisItemOpen Access
    Studies on Growth of Microalgae and Lipid Production in Dairy Industrial Effluent for Biodiesel Production
    (University of Agricultural Science, Dharwad, 2017-10) Sahana S.P.; Shirnalli, Geeta G.
    A study was conducted under laboratory conditions in the Department of Agricultural Microbiology, University of Agricultural Sciences, Dharwad during 2015-17 to evaluate growth of microalgae and lipid production from dairy industrial effluents for bio-diesel production. Untreated (W1) and treated (W2) dairy industrial effluent were collected from Karnataka Milk Federation Unit, Dharwad and were diluted with tap water at the rate of 20 (D1), 40 (D2), 60 (D3), 80 (D4) and 100 (D5) per cent. The initial physico-chemical parameters were analyzed and incubated for three weeks after inoculating with the microalgal strains viz., Chlorella MA-6 (S1), Chlorella MA-14 (S2), Botryococcus MA-5 (S3), Botryococcus sp. (S4) and Scenedesmus sp. (S5). The physico-chemical parameters of these effluent samples were analyzed and the growth of microalgae was measured in terms of biomass. The highest biomass was obtained in treated effluent with dilution D5 (100 %) and strain S1 (3.69 g/l) which was on par with untreated effluent of dilution D2 (40%) and strain S1 which showed 3.18 g/l. These treatments were selected for optimization of growth of microalgae using different nitrogen supplements viz., cow dung (N1), biogas spent slurry (N2), urea (N3) and di - ammonium phosphate (N4) used at the concentrations of 0 (C1), 0.1 (C2), 0.3 (C3), 0.5 (C4) and 0.7 (C5) per cent. The highest amount of biomass, lipid and chlorophyll content was obtained in treatment W2N1C5. The treated effluent without dilution supplemented with cow dung at 0.7 per cent concentration was optimum for the growth of microalgae Chlorella MA-6. The microalgae was harvested after three weeks and the lipid content obtained from the biomass was 23 ml (0.56 ml/g of microalgal biomass) and the biodiesel obtained was 20.83 ml (0.504 ml of biodiesel per gram of microalgae).
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    ThesisItemOpen Access
    Isolation, Characterization and Selection of Efficient Fluorescent Pseudomonads Against Sclerotium rolfsii and Colletotrichum truncatum of Soybean
    (University of Agricultural Science, Dharwad, 2017-10) Priyanka; Goudar, Geeta D.
    A study was made to isolate, characterize and select efficient fluorescent pseudomonads against Sclerotium rolfsii and Colletotricum truncatum in soybean, in the Department of Agricultural Microbiology, University of Agricultural Science, Dharwad. Sixty two fluorescent pseudomonads were isolated from 37 rhizosphere soil sample of soybean collected from Belagavi and Dharwad districts of Karnataka, during 2016. These isolates were subjected for their morphological, biochemical, physiological and functional characterization. All the isolates were gram negative rods, exhibiting light green, green, dark green and light orange coloured colonies under UV light. Fifty native fluorescent pseudomonads were tentatively identified as Pseudomonas fluorescens, 10 as P. aeruginosa and 2 isolates as P. aureofaciens strains based on Bergey’s manual of Determinative Bacteriology. With respect to functional characterization, fifty two isolates were positive for P- solubilization. Forty seven isolates were positive for hydrogen cyanide (HCN) production, among which 10 of the isolates were strong HCN producers. All the isolates were positive for siderophore production (6.00 to 36.37 mm). Whereas, indole acetic acid (IAA) and gibberlic acid (GA) production ranged from 39 to 28.03 and 0.5 to 18.52 g/25 ml of broth, respectively. Out of 62 isolates, 51 and 38 were inhibitory to S. rolfsii and C. truncatum respectively in dual plate technique. Seven potential isolates were selected for pot culture evaluation against both the pathogens. Under pot culture experiment, out of seven isolates, DFP48 exhibited highest plant growth promotional activity with least disease incidence of 13.09, 19.89, and 21.96 per cent at 15, 30 and 60 DAS respectively against S. rolfsii top soil challenge inoculated with 5 per cent of S. rolfsii. Similarly DFP54 showed maximum plant growth promotional activity and recorded least anthracnose disease incidence of 11.90 and 13.87 at 30 and 60 DAS respectively, against Colletotricum truncatum foliar spray inoculated with 105 CFU/ml (Colony Forming Unit).
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    ThesisItemOpen Access
    Bacterial Endophytes in Bioremediation of Sewage
    (University of Agricultural Science, Dharwad, 2017-07) Archana K.; Patil, C.R.
    A laboratory study was conducted aiming at isolating bacterial endophytes from the plant parts in contact with sewage. 13 plant samples were collected near by constructed wetland and along sewage drains of Hubli-Dharwad municipal corporation, Karnataka state were collected and used for isolation of endophytic bacteria. The surface sterilization procedure was standardized and a total of 109 (50 from root, 43 from leaf and 16 from stem) bacterial endophytes have been isolated. For all the isolates morphological (microscopic study and fluorescence ability) and biochemical (EPS production, Sugar utilization pattern and E.coli inhibition test) characterization were done. The isolates were tested for the traits suited to remediate sewage such as pH, EC, Biological Oxygen Demand, Chemical Oxygen Demand, Total phosphorus and Nitrate nitrogen. Out of which three isolates viz. E67, E84 and E104 were found very efficient as they reduced EC by 53 to 63 per cent, BOD by 66 to 70 per cent, COD by 50 to 55 per cent, nitrate nitrogen by 45 to 47 per cent and total phosphorus by 42 to 55 per cent when inoculated to sewage. These three efficient isolates in consortia were subjected to a pilot scale study both in the presence and absence of host plant (Bracharia mutica) under greenhouse conditions. Floating bed technique was followed with four treatments. Among the four treatments treatment 2 recorded the highest reduction of BOD (79.10 per cent), COD (78.73 per cent), pH (7.78), EC (0.11 dS/m), nitrate nitrogen (70.98 per cent) and total phosphorus (59.81 per cent) was best followed by treatment 4 recording a reduction in BOD (58.67 per cent), COD (76.45 per cent), pH (7.8), EC (0.14 dS/m), nitrate nitrogen (58.60 per cent) and total phosphorus (42.67 per cent) over control. The results revealed that the efficient isolates have ability to remediate sewage.
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    ThesisItemOpen Access
    Optimization of Cell Protectants, Adjuvant and Additives to Develop Liquid Formulation of Azospirillum
    (University of Agricultural Science, Dharwad, 2017-09) Patil, Sandesh; Patil, C.R.
    An effort was made to optimize the additives, adjuvant and surfactant for the growth and shelf life of liquid formulations of Azospirillum ACD-15 at the Institute of Organic Farming, University of Agricultural Sciences, Dharwad during 2014-15. Sodium malate broth was amended with additives such as polyethylene glycol at 0.5 and 1.0 per cent, trehalose at 5 and 10 mM and glycerol at 5 and 10 mM. Adjuvant like gum arabica at 0.15 and 0.30 per cent; surfactant like polysorbate - 20 at 125 and 250 ppm. A total of 32 combinations of formulations were developed and evaluated for their ability to support growth and higher populations of Azospirillum ACD-15 over a period of 72 h. Based on population dynamics only nine formulations with population more than 9.6 x 109 CFU ml-1 after 72 h were chosen for further incubation studies. These nine formulations were kept for shelf life study over a period of six months at both ambient and refrigerated conditions. Among them, formulation 2 under both conditions was found to be far superior to others in terms of the population of Azospirillum ACD-15 at all stages over 180 days of incubation. This formulation recorded the highest populations in terms of the most probable number estimation of Azospirillum ACD-15 under ambient condition (6.18 x 106 cells ml-1) and under refrigerated condition (1.07 x 106 cells ml-1). The population was also assessed by direct plate count technique with values of 1.58 x 109 cells ml-1 at ambient condition and 7.0 x 107cells ml-1 at refrigerated condition. In the present study, the cost involved in the production of this efficient formulation 2 was 376 litre-1 and 58 per cent of this cost was on one amendment trehalose (additive) alone. The results from this study clearly indicated that the liquid formulation of Azospirillum ACD – 15 was better in terms of viable population and shelf life compared to lignite formulation.
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    ThesisItemOpen Access
    Effect of Lactic Acid Bacterial Fermented Lantana camara Extract on the Growth and Yield of Green Gram (Vigna radiata L.)
    (University of Agricultural Science, Dharwad, 2017-05) Ganagi, Tanuja I.; Jagadeesh, K.S.
    In vitro studies were conducted at the Department of Agricultural Microbiology, University of Agricultural Sciences, Dharwad during 2016-17. Fifty isolates of lactic acid bacteria were tested for their tolerance to different concentrations (10, 20 and 30 %) of L. camara extract. Finally, two efficient isolates (DB 27 and T(JH)) were selected. The Lantana leaves fermented with these two lactic acid bacteria were compared for chemical, phytochemical and microbiological composition. Fermented product of isolate DB 27 showed the highest chemical, phytochemical and microbiological composition compared to other treatments. DB 27 also showed the proteolytic and lipolytic activity. The germination as well as seedling vigour index was significantly increased due to priming of seeds with Lantana Fermented Extract (LFE). Pot culture evaluation on spraying of LFE at different concentrations and number was carried out in green gram. Out of the two isolates, DB 27 resulted in the highest values in the growth parameters. LFE spraying twice @ 10 ml/l resulted in increased chlorophyll content by about 40 per cent. This treatment also significantly increased microbiological population both in the rhizosphere and phyllosphere, with a concomitant increase in the activities of critical soil enzymes such as dehydrogenase, urease and phosphatase. Spraying green gram seedlings with LFE significantly increased pod and grain yield. The highest pod yield (11.17 g/plant) and grain yield (10.58 g/plant) was obtained by spraying LFE, fermented with DB 27, sprayed twice @ 10 ml/l. The present investigation clearly brought out the potential of LFE in stimulating microbiological population and their activities in terms of soil enzymes eventually improving growth and yield of green gram.