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ThesisItem Open 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 NirmalnathThesisItem Open Access Nursery Inoculation of the Selected Vegetable Seedlings with A Microbial Consortium and its Field Performance in Brinjal (Solanum melongena L.)(University of Agricultural Science, Dharwad, 2016-06) Jayashree C.; Jagadeesh, K.S.A microbial consortium was prepared which consisted of Azospirillum ACD 15, Pseudomonas striata, potassium solubilizing bacterium KSB 27, Pseudomonas spp. B 15, Leuconostoc mesenteroides and Glomus macrocarpum after compatibility testing. This microbial consortium was mixed with cocopeat, a nursery medium used for raising vegetable seedlings in protrays. It was mixed at different doses viz., 1 g kg-1, 3 g kg-1 and 5 g kg-1 of cocopeat. Seeds of selected vegetables namely tomato, brinjal, chilli, capsicum, cabbage and cauliflower were sown in the treated cocopeat. The nursery studies revealed that the cocopeat treatment with the microbial consortium @ 5 g kg-1 of cocopeat was the best treatment. It helped in production of quality and healthy transplantable seedlings with better growth parameters. Further, the microbial consortium treated-brinjal seedlings were evaluated in a farmer’s field, with graded levels of NPK fertilizers. In general, the microbial consortium treated seedlings exhibited higher plant growth and yield parameters viz., plant height, chlorophyll content, biomass production, nutrient uptake and yield over uninoculated control. Among the treatments, the treatment receiving 50 per cent recommended level of NPK fertilizers showed significantly higher plant growth and yield parameters. The rhizosphere microbial population and enzymatic activities were also higher in the consortium-treated seedlings when compared to control. Microbial consortium with 50 per cent recommended level of NPK fertilizers was found to be the best treatment, which resulted in 17.06 per cent increase in the yield and better economic returns.ThesisItem Open Access Evaluation of Microbially Synthesized Zinc Nanoparticles on Growth and Yield of Maize (Zea mays L.)(University of Agricultural Science, Dharwad, 2016-06) Harish Kumar, K.; Savalgi, V.P.Soil samples from the fields of MARS, Dharwad were collected with the aim of isolating zinc solubilizing microorganisms. Available zinc content of soil was taken as base for sample collection. Out of 30 samples collected 15 samples from 0.1 to 0.38 ppm, 6 from 1.3 to 2.0 ppm and 9 from 2.1 to 2.5 ppm. Higher population of zinc solubilizers were found in lower zinc containing soil samples. Fungal isolates showing higher zone of zinc solubilization and higher zinc metal tolerance were selected and analyzed for the synthesis of zinc nanoparticles (ZnNP’s) by the incubation method. Characterization of microbial synthesized ZnNP’s was done by UV-Visible spectrometer, which exhibited a peak at 260 nm. Confirmation of this ZnNP’s was further done by Atomic Force Microscope which shown spherical shape. X-ray Diffraction (XRD) analysis revealed the presence of ZnNP’s with the 2Ɵ values of 31.74° and 36.23°. The sharp peaks exhibited in XRD graph indicated the presence of capping agent from the mother protein of the fungus. Out of 30 isolates, two fungal isolates viz., 3F and 9F were potent of producing zinc nanoparticles in size range of 20 to 60 nm. A pot culture experiment was conducted to study the effect of microbial synthesized and chemical synthesized ZnNP’s on growth and yield parameters of maize. ZnNP’s were applied as foliar spray at 30 and 60 days after sowing at different concentrations ranging from 250 to 1250 ppm. Microbial synthesized ZnNP’s spray of 750 ppm exhibited higher response of increased chlorophyll content and yield parameters over all other treatments. Soil enzyme activity of dehydrogenase and phosphatase were high in treatment receiving 750 ppm of microbial synthesized ZnNP’s. From the present study it is inferred that microbial synthesized ZnNP’s were more beneficial than chemical synthesized ZnNP’s at the same concentration of application. Foliar spray of 750 ppm was found to be optimum concentration for better growth and yield parameters of maize.ThesisItem Open Access Effect of Microbial Consortium on Growth, Yield and Quality Parameters of Onion (Allium cepa L.) Under Field Condition(University of Agricultural Science, Dharwad, 2016-06) Paravvagol, Shweta S.; Jagadeesh, K.S.After compatibility testing, a microbial consortium was developed which consisted of Azospirillum (ACD 15), Pseudomonas striata, K solubilizer (KSB 27), Pseudomonas sp. (B-15), Leuconostoc mesenteroides (LAB 82) and Glomus macrocarpum. Its effects on the growth, yield, nutrient uptake and rhizosphere microbiology of onion were assessed in a farmer’s field, at graded levels of NPK fertilizers. In general, the microbial consortium significantly improved all these parameters. The microbial consortium even at 50 per cent NPK level (T4) has significantly increased the plant growth andyield parameters, when compared to uninculated control with 100 per cent NPK (T1). This was found to be the best treatment with increased bulb yield of 23.35 per cent, besides saving 50 per cent NPK fertilizers. The nutrient uptake of N, P, K and S was also increased significantly due to the inoculation of the microbial consortium. The rhizosphere microbial population increased significantly, with a concomitant increase in dehydrogenase, phosphatase and urease activities, due to the inoculation of microbial consortium as compared to the control. Besides increasing yield and yield components, the microbial consortium also increased quality parameters. TSS content and pungency were found to be increased by 30.69 and 31.51 per cent respectively, due to inoculation of microbial consortium over control. Thus, the present study has indicated that the microbial consortium with 50 per cent NPK was the best treatment in getting increased growth, bulb yield, nutrient uptake and quality parameters in onion, with a saving of input cost on chemical fertilizers by 50 per cent.ThesisItem Open Access Development of Liquid Formulation of Pseudomonas Striata – A Phosphate Solubilizing Biofertilizer(University of Agricultural Science, Dharwad, 2016-01) Parvathi S.; Patil, C.R.Present study was conducted to develop liquid formulations of Pseudomonas striata, a phosphate solubilizing bacteria using different concentrations of additives, adjuvants, and surfactants. Out of the 32 liquid formulations developed, 12 formulations with population more than 5 x 1010 CFU ml-1, after 84 hr of growth were selected for shelf life studies. Formulation 18 with 10 mM glycerol, 0.5% PEG, 0.05% CMC, 0.15% GA and 250 ppm polysorbate 20, recorded the highest population of 3 x 1010 CFU ml-1 after six months of incubation and was used to optimize the dosage of liquid formulation required to treat maize and sorghum seeds. Results clearly indicated that for treating bold seeds such as maize only 2 ml kg-1 of seeds of this formulation showed higher inoculant survival on seeds (log10 6.72), seed germination (94 %), root length (20.59 cm), shoot length (17.92 cm) and seedling vigour (3620.43). Similarly, for treating small sized seeds such as sorghum 4 ml kg-1 seed of formulation was found optimal. It resulted in higher inoculant survival on seed (log10 5.36), root length (26.60 cm), shoot length (26.03 cm) and seedling vigour (489.33). However, the highest per cent germination (92.5%) of sorghum seeds was observed in seeds treated @ 6 ml kg-1 of this inoculum. The cost involved in developing a litre of the best liquid formulation was ` 149. While the cost of lignite based formulation was ` 60 kg-1 which normally is inoculated @ 20 g kg-1 seed, thus costing about ` 1.2 kg-1. However, our results indicated that only 2 to 4 ml of the liquid formulation was sufficient to treat one kg of seed which costed less than one rupee per kg of seeds, there by reducing the total cost of treating with biofertilizer by 50 - 75%.ThesisItem Open Access Isolation and Screening of Fungal Pathogens and Their Interactive Effect with Weevil [Neochetina bruchi (Hustache)] Against Water Hyacinth [Eichhornia crassipes (Martius)](University of Agricultural Science, Dharwad, 2015-12) Karthik M.C.; Jones Nirmalnath, P.An investigation was carried out to isolate and screen native fungal pathogens from infested water hyacinth plants of Karnataka during 2014-2015. The aquatic weeds exhibiting symptoms like spots, lesions, rots and browning were collected and followed tissue isolation method using potato dextrose agar medium in order to isolate associated fungal pathogens. After a period of four days pure culture of the fungal bio agents was obtained using hyphal tip or single spore isolation techniques and was screened for their disease causing ability on the water hyacinth by spraying with spore suspensions from each fungal isolate, while the control plants were sprayed with sterilized water. Based on the disease severity index three promising isolates viz., Colletotrichum sp., Alternaria sp. and Cercospora sp. were selected for further studies integrating with Neochetina bruchi. In the in vivo experiment, the weevils were introduced to the plants a week before the spray of the fungal pathogens in order to get enough weevil feeding scars to serve as entry point for the fungal spores. Among the different treatment combinations, highest per cent of disease severity and reduced chlorophyll content was recorded with the treatments received dual inoculation of Colletotrichum sp. along with Neochetina bruchi. Furthermore, the treatment received dual inoculation recorded lowest photosynthetic rate and stomata conductance, while the leaf temperature and transpiration rate were found to be increased with the dual inoculation. Thus, our preliminary findings are the indicative of the effectiveness of Colletotrichum sp. along with Neochetina bruchi that can be a promising biotic tool for the management of water hyacinth.ThesisItem Open Access Studies on Phosphate Solubilizing Actinomycetes(University of Agricultural Science, Dharwad, 2015-07) Jagadeesh Yadav, D.K.; Shirnalli, GeetaActinomycetes are known for degradation of lignocellulose complex and antagonistic activity, but their role in Phosphours (P) solubilization activity is scanty. Hence, the present study was conducted to isolate P-solubilizing actinomycetes and test their multifunctional activities and their performance on growth and yield parameters of groundnut crop under pot culture at the Department of Agricultural Microbiology, University of Agricultural Sciences, Dharwad, Karnataka. Soil samples collected from various sources were subjected for isolation of actinomycetes. A total of 157 isolates were obtained and screened for P- solubilisation activity on Pikovskaya’s medium and modified Sperber’s media containing tri-calcium phosphate (TCP) and K2HPO4 respectively as source of P. Among the 20 isolates that exhibited P- solubisiation activity, 9 isolates were efficient in solubiilising TCP in terms of zone of solubilisation (3.0 to 15.0 mm) and release of inorganic P (7.37 to 13.14%). Among these, the isolates PSA-3, PSA-5 and PSA-7 exhibited maximum P- solubilisation activity. The production of organic acids by these isolates support the solubilisation activity. The selected 25 isolates exhibited multifunctional activities such as zinc solubilisation, hydrolysis of cellulose and starch, production of organic acids, utilization of carbon source and PGPR activities (IAA, GA, Siderophore, HCN and antagonistic activity). The three efficient P-solubilising isolates also exhibited maximum of these activities and hence tested in single and in combinations on the growth and yield parameters of groundnut plants in green house conditions. The treatment PSA-3 + PSA-5 + PSA-7 + (50% RP + 50% SSP) was the most promising treatment which was on par with the reference strain (P.striata) in terms of growth parameters, microbial activities and pod yield. Therefore, it was concluded that this treatment has potential to be used as bioinoculants in groundnut. The 16S rRNA sequence analysis showed that PSA-5 was Streptomyces badius and PSA-7 was Streptomyces bellus.ThesisItem Open Access ISOLATION, CHARACTERIZATION, SCREENING AND SELECTION OF AN EFFICIENT AM FUNGUS FOR ASHWAGANDHA (Withania somnifera L.)(University of Agricultural Sciences, Dharwad, 2014-11) NAGARAJ S. B.; Dr. M. N. SREENIVASAAshwagandha (Withania somnifera L.) has tremendous medicinal values. The ashwagandha berries and leaves are locally applied to tumors, tubercular glands, carbuncles and ulcers. The main active constituents are alkaloids and steroidal lactones. These include tropine and cuscohygrine. In Ayurveda, Withania is widely claimed to have potent aphrodisiac, sedative, rejuvenative and life prolonging properties. The present study emphasized the isolation, characterization, screening and selection of arbuscular mycorrhizal (AM) fungi from ashwagandha growing areas of Karnataka. The efficient AM fungal isolates were tested at different phosphorus levels, Mycorrhizal dependency and mycorrhizal inoculation effect on ashwagandha was also worked out. Further, an attempt was made to produce manoxinic culture of AM fungus in artificial media. Additionally, the growth promoting ability of efficient AM fungal isolate was evaluated in pot as well as in field condition. The results of this study clearly brought out AM-G-9a to be an efficient isolate of AM fungus for ashwagandha as it might have a better adoptability to the local conditions. The inoculation of this isolate resulted better plant nutrition, alkaloid content, growth and yield of ashwagandha in both pot and field condition. The shelf life of soil based inoculum was 3 months at room temperature while it was 5 months under refrigerated condition.ThesisItem Open Access ISOLATION AND SCREENING OF ARBUSCULAR MYCORRHIZAL FUNGI FOR SUPPRESSION OF STRIGA, A PARASITIC WEED IN SUGARCANE(University of Agricultural Sciences, Dharwad, 2015-06) SHUBHA CHIMMALAGI; Dr. P. JONES NIRMALNATHAn investigation was carried out to isolate native AM fungal (AMF) isolates from the Striga suppressive soils of sugarcane growing areas of northern Karnataka. Further, sixteen native AMF isolates were screened for their ability to suppress Striga as well as plant growth promotional abilities in sugarcane under pot culture studies. The pots were filled with Striga infested soil prior to the planting of sugarcane sets of equal bud size. AMF inoculum @ 150 g pot 1 was mixed thoroughly with the top10 to 15 cm of the soil and pots were treated with Hoagland’s nutrient solution once a week. The data on the emergence of Striga, Striga biomass, plant height, chlorophyll content and soil microbiological activities were recorded. The striga emergence was significantly inhibited in the treatment received standard AMF consortium, followed by AMF native consortium, UASDAMF -2, UASDAMF-5, UASDAMF-9 and UASDAMF-12. While, the UIC recorded highest number of striga infestation. Furthermore, the plant height, chlorophyll content, soil enzyme activities and spore load/ 50gm of soil were recorded highest with native AMF consortium over uninoculated control. Thus, our preliminary findings are indicative of the effectiveness of AMF in protecting Sugarcane against Striga infestation and hence can be a promising strategy to develop a biological tool for Striga control.
