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Assam Agricultural University, Jorhat

Assam Agricultural University is the first institution of its kind in the whole of North-Eastern Region of India. The main goal of this institution is to produce globally competitive human resources in farm sectorand to carry out research in both conventional and frontier areas for production optimization as well as to disseminate the generated technologies as public good for benefitting the food growers/produces and traders involved in the sector while emphasizing on sustainability, equity and overall food security at household level. Genesis of AAU - The embryo of the agricultural research in the state of Assam was formed as early as 1897 with the establishment of the Upper Shillong Experimental Farm (now in Meghalaya) just after about a decade of creation of the agricultural department in 1882. However, the seeds of agricultural research in today’s Assam were sown in the dawn of the twentieth century with the establishment of two Rice Experimental Stations, one at Karimganj in Barak valley in 1913 and the other at Titabor in Brahmaputra valley in 1923. Subsequent to these research stations, a number of research stations were established to conduct research on important crops, more specifically, jute, pulses, oilseeds etc. The Assam Agricultural University was established on April 1, 1969 under The Assam Agricultural University Act, 1968’ with the mandate of imparting farm education, conduct research in agriculture and allied sciences and to effectively disseminate technologies so generated. Before establishment of the University, there were altogether 17 research schemes/projects in the state under the Department of Agriculture. By July 1973, all the research projects and 10 experimental farms were transferred by the Government of Assam to the AAU which already inherited the College of Agriculture and its farm at Barbheta, Jorhat and College of Veterinary Sciences at Khanapara, Guwahati. Subsequently, College of Community Science at Jorhat (1969), College of Fisheries at Raha (1988), Biswanath College of Agriculture at Biswanath Chariali (1988) and Lakhimpur College of Veterinary Science at Joyhing, North Lakhimpur (1988) were established. Presently, the University has three more colleges under its jurisdiction, viz., Sarat Chandra Singha College of Agriculture, Chapar, College of Horticulture, Nalbari & College of Sericulture, Titabar. Similarly, few more regional research stations at Shillongani, Diphu, Gossaigaon, Lakhimpur; and commodity research stations at Kahikuchi, Buralikson, Tinsukia, Kharua, Burnihat and Mandira were added to generate location and crop specific agricultural production packages.

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20183
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Subject: Plant Pathology × End date: 2018 × Start date: 2018 × Thesis Type: Ph.D ×
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    ThesisItemOpen Access
    PURIFICATION, ANTISERA PRODUCTION AND DEVELOPMENT OF DIAGNOSTIC KIT AGAINST POTATO VIRUS Y
    (AAU, Jorhat, 2018-07) Mishra, Ranima; Nath, P. D.
    Purified viral protein of Potato virus Y (PVY) was isolated from PVY culture maintained on potato (Solanum tuberosum L.) plants. The average concentration of the purified protein was found to be 153.1 ng/ μl with an average yield of 0.449 mg virus per gram of fresh plant tissue. Presence of flexuous filamentous virus particles with an average length of 590 nm in the purified viral suspension was confirmed by Transmission electron microscopy. PVY purified virus preparation was used for immunizing rabbit for production of polyclonal antisera. Good quality antisera were collected one week post boosters (AS4b, AS5b, AS6b and AS7b). The IgG fractions from these four antisera were tested for the detection of PVY by DAS-ELISA with universal anti- rabbit enzyme conjugate as secondary antibody, resulted high specificity with the known PVY infected samples. The assay was compared with the commercial DAS-ELISA kit (Bio Reba, AG, Switzerland). Among the antisera, AS6b was showing the highest mean absorbance value for all positive samples (2.210) which was at par the value shown by the commercial kit (2.250) and these were followed by AS5b (1.680), AS7b (0.929) and AS4b (0.362), respectively. AS6b was showing the highest mean absorbance values for the leaf extracts of samples which were statistically at par with the values shown by the commercial kit. IgG titres for the four batches were measured using a series of IgG dilutions from 10-3 to 10-6 with conjugate and sample dilutions at 10-3 and 100, respectively. Significant differences were observed in the titres of these four batches of IgG at 10-3 dilution. At that dilution, AS6b showed the highest mean absorbance value (1.272) followed by AS5b (1.009), AS7b (0.806) and AS4b (0.522), respectively. In DAS- ELISA with sap dilutions where IgG and conjugate dilutions were constant at 10-3, no significant differences observed in the mean absorbance values of all IgG batches at each sap dilutions and similar trend was observed, among the antisera batches, in sensitivity of IgG towards diluted samples. The AS6b showing the overall highest mean values followed by AS5b and AS7b, respectively. Finally, IgG batch 6b (AS6b) was selected and tested by a simple and rapid tissue/ dot- print immunoassay against PVY. The AS6b showed a highly specific reaction with dot- prints of PVY infected plants at IgG (AS6b) and IgG conjugate dilutions of 10-3. The test was done with sap dilutions of 1:1, 1:2, 1:4, 1:8, 1:16, 1:32 and 1:64 (V/V). AS6b could detect presence of PVY by showing the desired purple coloured reaction up to 1:8 sample dilution. Molecular characterization of PVY from PVY infected samples of Jorhat district, Assam was also carried out through reverse-transcriptase polymerase chain reaction (RT-PCR) assay resulting in desired 328 bp amplicon. Partial sequencing of RT-PCR product and phylogenetic analysis revealed that the virus is closely related to Potato virus Y worldwide isolates.
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    ThesisItemOpen Access
    DEVELOPMENT OF IPDM MODULE FOR CULTIVATION OF BRINJAL
    (AAU, Jorhat, 2018-01) Upamanya, Gunadhya Kumar; Dutta, Pranab
    Brinjal growers of Assam completely depend on the chemocentric cultivation practices to combat harmful pests and diseases, which not only increase the cost of cultivation but also affect consumers with pesticide residues. Moreover, the indiscriminate use of chemical pesticides, fertilizer etc. also causes harm to the environmental matrix. Development of an alternative eco-friendly IPDM module for sustainable production of the crop is the need of the hour. The present study was done on development of a consortia of phytopathogenic biocontrol agent, entomopathogens together with application of the consortial formulation biofertilizers with an aim to get a combine effect against diseases, pests and simultaneously supply of major nutrients for organic cultivation of brinjal. In vitro dual culture study showed that out of six (6) biocontrol agents T. harzianum showed marked inhibition against Rhizoctonia solani (74.44%), Fusarium solani (70.68%), Alternaria melongenae (72.48%), Sclerotinia sclerotiorum (69.15%) and Phomopsis vexans (77.82). In another in vitro study done in pot condition, M. anisopliae (@1X10 8 spores/ml of water) was found better in reduction of population of sucking pests like aphid (64.87%), jassid (57.74%), and white fly (63.80%). On the other hand, B. bassiana was found better for hadda beetle with 67.16% reduction in population. B. bassiana was also found to be the superior in reduction of brinjal shoot and fruit borer (per cent shoot infestation=9.34, Percent fruit infestation by number=11.73 and by weight=14.32). Compatibility study done by coculture method showed that amongst the tested biocontrol agents, T. harzianum and two entomopathogens viz., B. bassiana and M. anisopliae were found to be compatible. Based on the in vitro study a liquid consortial formulation with three best biocontrol agents viz., T. harzianum, B. bassiana and M. anisopliae was prepared with already standardized additives (Department of Plant Pathology, AAU, Jorhat). Shelf life study showed that the consortia can retain 45% viability up to 6 months at room temperature and up to 54% at 40C and 64% viability at -200C for a year. Pot and field experiment conducted at Mycology Research Section and organic block of Experimental Farm, Department of Horticulture, AAU during 2014-15 to test the efficacy of six different IPDM modules showed that module-6 (seed treatment + seed bed treatment in nursery + soil application in main field + seedling dip treatment with consortia of biofertilizer, Rhizobium sp, Azotobacter sp strain 52, Azospirillum sp strain 71 and Bacillus sp strain 5 W + spraying of BCA) was the best in the management of pests (aphid, jassid, hadda beetle and brinjal shoot and fruit borer) and diseases (Phomopsis leaf blight and fruit rot, Alternaria leaf spot, Fusarium wilt) of brinjal. Field experiment was conducted at KVK, Barpeta during 2015-16 to study the efficacy of the six modules against pest and disease management and growth parameters of brinjal and module 6 was found best for controlling pest and disease incidence with increased growth parameters and yield of the crop. Result of pooled analysis of field experiment showed an yield of 570.97 q/ha with B:C ratio 3.99. The module was also found effective in improving the nutrient status with significant increase of P and K status of soil and with microbial biomass carbon in both the years of experiment (2014-15 and 2015-16). Further, the module was tested in farmer’s field as OFT and comparison was made with farmer’s practice i.e, use of cypermethrin 10% EC and carbendazin 50% WP and chemical fertilizer @ NPK 50:50:50 kg/ha. Result showed that the developed IPDM module can curb the pests and disease complex of brinjal with farmer’s practice (application of chemical pesticides). An yield of 442.10 q/ha with B:C ratio of 3.48 was obtained in the best module which was at par with the farmer’s practice (yield= 449.56 q/ha and B:C ratio= 3.12). Post treatment nutrient status and physical properties of soil was found statistically non significant except the status of P which was significantly higher in farmer’s practice. However, the soil microbial biomass carbon was found statistically superior in the tested module (834.10 μg/g of soil) over farmer’s practice (351.74 μg/g of soil) and control (362.56 μg/g of soil).The module can be used by farmers for organic cultivation of brinjal after multilocational field trial in different agroecological condition of Assam.
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    ThesisItemOpen Access
    DEVELOPMENT OF NEXT-GEN NANO-BIO FORMULATION OF Trichoderma FOR SEED TREATMENT OF VEGETABLE CROPS
    (AAU, Jorhat, 2018-01) Boruah, Sarodee; Dutta, Pranab
    Trichoderma is a potential antagonistic biological control agent for the management of soil borne and aerial plant pathogens. Trichoderma based bioformulations has been developed by different scientists throughout the world with effective field results. Chitosan nanoparticles have various applications due to its biodegradable and non- toxic properties. It can elicit natural innate defense responses within the plant system to resist plant diseases. Trichoderma spp. can be stimulated for production of chitinase by addition of nano chitosan in its bioformulation. In the present study, chitosan nanoparticles were synthesized from four different fungus viz., Fusarium oxysporum, Metarhizium anisopliae, Beauveria bassiana and Trichoderma viride and one commercial product of chitosan (Sigma Aldrich) was taken for comparison. Synthesized nanoparticles were characterized by using UV-VIS Spectroscopy, Fourier transform infrared spectrometer (FTIR), Zetasizer, Dynamic Light Scattering (DLS) and Transmission Electron Microscopy (TEM). Formation of chitosan nanoparticles (NPs) were confirmed by UV-VIS spectroscopy study with absorption peaks at the range of 310.02 to 342.00 nm. FTIR study showed that synthesized chitosan NP has all the required functional groups like OH, N-H, C-H, C=O, C-O, C-N and P=O. Study on surface properties of NPs by using zetasizer resulted that chitosan NPs synthesized from F. oxysporum, M. anisopliae, B. bassiana, T. viride and commercial product were found to be positively charged and were stable in nature with zeta potential of 3.24, 18.6, 5.4, 9.78 and 17.6 mV respectively. Electron microscopy study showed that the shape of NP as nearly spherical. DLS analysis showed the average size of the chitosan NPs synthesized from F. oxysporum, M. anisopliae, B. bassiana, T. viride and commercial products as 273.20, 172.50, 78.36, 89.03 and 300.10 nm respectively. Compatibility with T. asperellum study showed that nano chitosan at all the tested concentrations (@ 0.01, 0.02 and 0.03 per cent) were compatible. Study on in vitro efficacy against three soil borne plant pathogens viz., Fusarium oxysporum, Sclerotium rolfsii and Rhizoctonia solani showed that the combination of T. asperellum and chitosan NP was superior in inhibiting the mycelial growth of the tested pathogens as compared to the recommended chemical @0.1 per cent. Nanochitosan based liquid formulation of T. asperellum was prepared and energy dispersive X- ray spectroscopy (EDX) study showed the presence of the required elements with per cent atomic weights. Further, study on in vitro bioefficacy of the nanobioformulation showed highly effective result with highest radial growth inhibition percentage of 62.07, 47.85 and 63.25 per cent against F. oxysporum, S. rolfsii and R. solani respectively. Seeds treated with nanobioformulation @ 0.3 per cent could protect the crops upto 47.02, 50.00 and 60.00 per cent at 50 days after sowing in pea, tomato and cabbage respectively over control with significant increase in growth as well as physiological parameters.