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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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ThesisItem Open Access MORPHOLOGICAL AND BIOCHEMICAL BASES OF RESISTANCE OF CERTAIN CHILLI GERMPLASMS AGAINST YELLOW MITE, Polyphagotarsonemus latus (BANKS)(AAU, Jorhat, 2021) Hussain, Nasreen; Rahman, SahidurThe present experiment was carried out to investigate the morphological and biochemical bases of resistance of certain chilli germplasms against yellow mite. The experiment was conducted at Instructional-Cum-Research (ICR) Farm and Department of Entomology, Assam Agricultural University, Jorhat during 2020-21. The seasonal incidence of yellow mite of chilli was assessed on weekly basis from February, 2021 to May, 2021. Activity of yellow mite was observed from second week of February. The mean mite population was highest during last week of March, 2021 with 23.70 number of mites per 3 leaves and the least was found as 0.10 mites per 3 leaves during first week of May, 2021. The mean mite population showed significant negative correlation with evening relative humidity (r = 0.525) and rainfall (r = 0.501) whereas significant positive correlation (r = was shown with maximum temperature Based on mean mite population, germplasms were categorized as, highly resistant (Moni, Yellow mem, Green mem, Krishna with <5 mites per 3 leaves), moderately resistant (Purple, Diphu with 10-20 mites per 3 leaves), susceptible (Jati tez, Jati suti with 20-30 mites per 3 leaves) and highly susceptible (Bhekuri, Khorika, Birds’s eye, Bhut jolokia with >30 mites per 3 leaves). The correlation studies between the population of the yellow mite and different morphological and biochemical characters revealed that yellow mite had a significant negative correlation with trichome density (r = -0.847), while leaf area had significant positive correlation (r = 0.651). Among the biochemical parameters taken, total soluble sugar (r = 0.945) and total soluble protein (r = 0.804) had positive significant correlations with mite infestation and total phenolic compounds had significant negative correlation (r = -0.668). Therefore, resistant germplasms had greater trichome density and higher phenolic compounds in leaves which confer red resistance against yellow mite. Thus, the desirable characteristics may be incorporated for development of resistant varieties through breeding.ThesisItem Open Access IMPACT OF CERTAIN NEWER INSECTICIDES ON SOIL FAUNAL DIVERSITY IN FRENCH BEAN (Phaseolus vulgaris L.)(AAU, Jorhat, 2021) Nath, Gourismita; Bhagawati, SudhansuLaboratory and field experiments were carried out in the Department of Entomology; Department of Plant Pathology and Horticulture Experimental Farm of Assam Agricultural University, Jorhat during 2020-21 to study the impact of certain newer insecticides on soil faunal diversity in French bean. Six newer insecticides viz., clothianidin 50 WDG, fipronil 0.3 G, thiamethoxam 25 WG, imidacloprid 70 WG, chlorantraniliprole 0.4 GR and fipronil 40%+ imidacloprid 40% WG were selected for conducting the experiment. Sampling for soil macro and microarthropods as well as soil microbial population were done at pre-treatment, 15, 30, 45 60 and 75 days after treatment (DAT). The soil macroarthropods were sampled using pitfall traps whereas the microarthropods were extracted through Tullgren Funnel. Assessment of soil microbial population was done by following the standard pour plate method. Experimental results revealed the hymenopterans as the most dominant group (54.74%) among the different soil macroarthropods observed prior to the application of insecticides followed by Coleoptera (13.68%) and Araneae (11.57%). Among the soil microarthropods, the abundance of Collembola and Oribatida were recorded to be 64.72 and 35.28 per cent, respectively in the pre-treated plots. The number of soil macroarthropods was ranged between 89.00 to 95.33/plot prior to the application of insecticides which showed statistical parity with each other. At 15 DAT, the abundance of soil macroarthropods in all the treated plots were reduced significantly (47.33-52.67 numbers) compared to the untreated control (89.33 numbers). However, maximum number of soil macroarthropods/ plot was recorded in chlorantraniliprole 0.4 GR treated plots (52.67) followed by clothianidin 50 WDG (50.33) and thiamethoxam 25 WG (49.67) treated plots. Perusal of data in respect of 30, 45, 60 and 75 days after treatment also showed a significant decrease in the numbers of soil macroarthropods as compared to the control, however, a gradual increase in the total number of soil macroarthropods was observed in each treated plots from 30 DAT onwards. Soil microarthropods obtained in different plots prior to the application of insecticides was ranged between 458.33 to 555.56 numbers/sq. m. All the insecticidal treatments did not exhibit any significant (p=0.05) impact on soil microarthropod population during the experimental period. 7 Assessment of soil microbial population revealed a significant decrease in the total bacterial (58.67-62.67) and fungal (48.00-51.67) population (cfu×104/g of soil) in all the treated plots at 15 DAT as compared to the control (98.67 bacterial and 91.67 fungal cfu×104/g of soil, respectively). However, maximum number of both the bacterial and fungal colonies (cfu×104/g of soil) were recorded in chlorantraniliprole 0.4 GR treated plots (62.67 and 51.67, respectively) followed by clothianidin 50 WDG (62.00 and 51.00, respectively) and thiamethoxam 25 WG (61.33 and 50.33, respectively) treated plots. A similar trend of results were also observed while the total population of bacterial and fungal colonies were assessed at 30, 45, 60 and 75 DAT. However, a gradual increase in the total bacterial and fungal population was observed in each treated plots from 30 DAT onwards showing the ability to overcome the toxic effect of insecticides by the microbes in the subsequent period of the experiment.ThesisItem Open Access Evaluation of dry powder of certain chilli cultivars with emphasis on capsaicin against Sitophilus oryzae (Coleoptera: Curculionidae) on wheat(AAU, Jorhat, 2021) V, Rakesh; Patgiri, PulinThe weevil, Sitophilus oryzae is considered the most important primary pest of stored wheat. Secondary metabolites like capsaicinoids extracted from chilli can be used in insect pests control as a potential alternative to synthetic insecticides. Therefore, the present study aimed to test the contact and fumigation repellency test of capsaicin from different chilli cultivars viz., Kashmiri, Guntur Sannam (S4), Jwala, Bullet and Bhut Jolokia collected from various zones of India. For this a modified cup bioassay apparatus was designed by altering the structural features of cup bioassay apparatus without changing its core principle, Consisting of outer big and inner small polyacrylic box with 2 mm perforations at the inner box on all four sides and bottom side, this can hold test grains up to 500 g. capacity. The repellency bioassay was also conducted using the area preference method. The results revealed that the treatments with the chilli cultivar Bhut Jolokia at a concentration 0.50 % (w/w basis), concentration at 10 ml and 5 g proved to be effective against all treatments and control under contact and fumigation repellency test of capsaicin respectively. And the percentage repellency was noted to be the highest in the treatments with Bhut Jolokia at a concentration of 5 ml (63.33 %). Therefore, capsaicin from the Bhut Jolokia chilli cultivar in its dry powder, ethanol extract and crude form performed well in repelling the maximum number of the test insects that it may be employed as the grain protectant against S. oryzae. Future research efforts may be made to focus on the evaluation of these molecules in specific trap tests to evaluate their efficacy in increasing pheromone trap captures.ThesisItem Open Access EVALUATION OF CERTAIN PLANT PRODUCTS AND CHEMICALS AGAINST BANANA LEAF AND FRUIT SCARRING BEETLE, Nodostoma subcostatum Jacoby (COLEOPTERA: CHRYSOMELIDAE)(AAU, Jorhat, 2021) Gogoi, Karanika; Gogoi, IneeField experiments were conducted in the Horticulture Experimental farm, Department of Horticulture, Assam Agricultural University, Jorhat during 2020-21 to evaluate certain plant products and chemicals against banana leaf and fruit scarring beetle, Nodostoma subcostatum Jacoby. The seasonal abundance of leaf and fruit scarring beetle on Dwarf Cavendish (Jahaji) was assessed on weekly basis from May, 2020 to April, 2021. The mean beetle population was highest during August, 2020 and the least was during January, 2021. Several meteorological factors have influenced the fluctuation of the scarring beetle population. For field evaluation, the treatments were applied at three critical stages of growth of the banana plant and among the treatments tested, imidacloprid 17.8 SL @20 g a.i./ha was the best effective treatment in all the three stages of the crop in reducing the beetle population i.e., at 3, 7 and 10 days after treatment, followed by NSKE 1500 ppm @3ml/L and lambda-cyhalothrin 5%EC @0.3ml/L. Among the plant extracts used, Xanthium strumarium @ 10 per cent stood out as the highest in minimizing the beetle population and the infestation over the other two plant extracts viz. Lantana camara and Pongamia glabra @10 per cent respectively. Imidacloprid 17.8 SL efficiently recorded as the best treatment in reducing the number of leaf scars per 5 cm2 leaf surface area whereas Pongamia glabra was the least effective. Reduction in fruit damage was also exhibited best by imidacloprid 17.8 SL (8.23 %) treatment followed by NSKE 1500 ppm (12.44 %), lambda-cyhalothrin 5% EC (16.45 %), Xanthium strumarium (19.28 %), Lantana camara (34.10 %) and Pongamia glabra (36.4 %). The present experiment brought out a conclusion that plants which possess insecticidal properties can be used as an alternative for synthetic insecticides and also in combination with synthetic insecticides, it can further amplify the management strategies in reducing the pest damage.ThesisItem Open Access EFFICACY OF CERTAIN NEWER INSECTICIDES AGAINST TERMITE, Odontotermes obesus AND RED ANT, Dorylus orientalis(AAU, Jorhat, 2021) Sarmah, Kasturi; Bhattacharyya, Badalpresent study was carried out to evaluate the efficacy of three newer insecticides (imidacloprid 70 WG, clothianidin 50 WDG and thiamethoxam 25 WG) against termite, Odontotermes obesus and red ant, Dorylus orientalis during 2020-21 in the AlNP- Soil Arthropod Pests Laboratory, Department of Entomology, AAU, Jorhat. Experimental findings revealed that among the three insecticides, thiamethoxam was found to be the most effective against termites with the highest per cent mortality of 42, 58, 74 and 95 per cent after 6, 12, 18 and 24 hours, respectively, at 100 ppm concentration. It was followed by clothianidin with 34, 45, 65 and 75 per cent mortality after 6, 12, 18 and 24 hours at 100 ppm concentration. For imidacloprid per cent mortality was registered as 33, 45, 62 and 68 per cent after 6, 12, 18 and 24 hours, respectively at 100 ppm concentration. The results also revealed that per cent mortality of termites increased gradually with increase in concentration as well as exposure period. The order of toxicity to O. obesus with respect to LC50 values at 24 hours after insecticidal treatment was thiamethoxam (2.59 ppm) > clothianidin (5.62 ppm) > imidacloprid (9.84 ppm). The order of toxicity with respect to LT50 values at 100 ppm concentration was thiamethoxam (8.22 hour) > clothianidin (11.32 hour) > imidacloprid (12.32 hour). Similarly, the data on mortality of D. orientalis revealed that among the three insecticides, thiamethoxam was found to be most effective with the highest per cent mortality of 64, 90, 100 and 100 per cent after 6, 12, 18 and 24 hours, respectively, at 1000 ppm concentration. Imidacloprid and clothianidin treatment registered per cent mortality 46, 58, 86, 98 and 26, 56, 98 and 100 per cent after 6, 12, 18 and 24 hours, respectively, at 1000 ppm concentration. Moreover, the per cent mortality of red ants increased gradually with increase in concentration of insecticides as well as exposure period. The order of toxicity to D. orientalis with respect to LC50 values after 24 hours exposure period was thiamethoxam (8.52 ppm) > clothianidin (14.93 ppm) > imidacloprid ( 31.88 ppm). The order of toxicity with respect to LT50 values at 1000 ppm concentration was observed as thiamethoxam (5.02 hour) > imidacloprid (7.53 hour) > clothianidin (9.03 hour).ThesisItem Open Access EFFECTS OF DIFFERENT POLLINATOR ATTRACTANTS ON INSECT POLLINATOR AND YIELD OF TORIA (Brassica rapa cv. Toria)(AAU, Jorhat, 2021) Kachari, Rani Amchi; Deka, Mukul Kr.The study, entitled ‗‗Effects of different pollinator attractants on insect pollinators and yield of toria (Brassica rapa cv. Toria)‘‘ was carried out at the ICR Farm, Assam Agricultural University, Jorhat campus during two consecutive rabi season i.e. October- 2018 to February-2019 and October-2019 to February-2020, using five different indigenously available insect attractants viz., jaggery @10 per cent concentration, sugarcane juice @10 per cent concentration, sugar solution @10 per cent concentration, papaya fruit extract @10 per cent concentration, banana fruit extract @10 per cent concentration along with open pollinated plot without any attractants and caged plot to evaluate their influence on attracting pollinators and quantitative parameters of toria. The study on the forager complex of toria revealed total of 20 different insect pollinators visiting the toria plot treated with jaggery @10 per cent concentration, during peak period of blooming comprising (10 Hymenoptera, 6 Diptera, 3 Coleoptera, 1 Lepidoptera). The common insect visitors in toria ecosystem observed were Indian bee (Apis cerana), rock bee (Apis dorsata), little bee (Apis florea), European/Italian honeybee (Apis mellifera), stingless bee (Tetragonula iridipennis), carpenter bee (Xylocopa tenuiscopa, X. fenestrata, X. leucothorax), syrphid fly (Syrphus sp.), wasp (Vespa magnifica), hover fly (Eristalinus tabanoides, Eristalinus arvorum), yellow wasp (Polistes hebreus), cabbage butterfly (Pieris rapae), ladybird beetle (Coccinellatrans versalis, Coccinella septempunctata, Coccinella sexmaculata), marmalade hoverfly (Episyrphus balteatus), ant (Monomorium indicum), housefly (Musca domestica), wasp moth (Amata huebneri) etc. Among the different insect foragers of toria, Apis cerana was the dominant forager constituting (49.09%) followed by Apis dorsata (7.89%), Apis melliferra (4.66%), Eristalinus sp. (6.89%), Apis florea (2.55%), wasp (5.09%), Xylocopa sp. (6.32%), Coccinella sp. (3.59%), Musca domestica (2.56%), Tetragonula irridipennis (2.34%), Pieris sp. (1.03%), Syrphus sp. (4.66%), Monomorium inidicum (2.05%) etc. The appearance, peak and cessation activity for most of the insect pollinators was recorded during 06.00 am - 07.00 am, 09.00 - 11.00 am and 04.00 - 05.00 pm, respectively. Jaggery @10 per cent concentration and sugarcane extracts @10% followed by sugar solution @10 per cent concentration was found superior in attracting the 6 pollinators and recorded maximum no. of different species of pollinators (21 no.s, 14 no.s and 13 no.s, respectively). Foraging behaviour of different pollinator reveals that time spent by the pollinators were more in the sugarcane treated plots followed by jaggery treated plots and least were recorded in controlled plot. Likewise, spraying of jaggery @10 per cent concentration was noted to have the highest seed yield (07.10q/ha) followed by sugarcane extract @10 per cent concentration and sugar solution @10 per cent concentration which recorded seed yield of (6.41q/ha) and (5.67q/ha), respectively. Caged crop (1.60 q/ha) and open pollinated crop (2.30q/ha) without any attractants recorded less number of pollinators and lowest yield during both the years of observations.ThesisItem Open Access Effect of certain plant extracts against Tea looper; Hyposidra talaca Walker, Geometridae : Lepidoptera(AAU, Jorhat, 2021) Dutta, Panchamika; Gogoi, IneeLaboratory experiments were conducted in the Department of Entomology, Assam Agricultural University, Jorhat during 2018-2020 to evaluate the bioefficacy of five different plant extracts which had been extracted with cold water viz.,Sapindus saponaria, Annona squamosa, Lantana camara, Vitex negundo and Xanthium strumarium had been done against the larva of Hyposidra talaca. Different concentrations of plant extracts along with the untreated and a standard check (Deltamethrin 2.8 EC) were taken for comparison. The result reveal that the highest mortality of 90.0% at 10.00% concentration followed by 63.66%, 56.66%, 53.33%, 50% and 43.33% at 7.5%, 5%, 2.5%, 1% and 0.5% concentrations respectively at 72 hours after treatment when the larva were treated with X. strumarium. The data of A. squamosa showed lowest mortality of 56.83% at 10.00 % concentration followed by 53.5%, 46.8%, 40.1%, 36.76% and 20.03% at 7.5%, 5%, 2.5%, 1% and 0.5% concentration respectively at 72 HAT. The leaf extracts of all the five plant extracts reveals a dose and time dependent mortality over the exposure period. While investigating the toxicity of plant extracts, the LC50 values of, S. saponaria, A. squamosa, L. camara, X. strumarium and V. negundo were found to be 3.464%, 4.228%, 3.549%, 1.334% and 3.648% at 72 HAT. The order of toxicity with respect to LC50 of all the plant extracts was Agora (Xanthium strumarium)>Monisaal (Sapindus saponaria)>Gu phool (Lantana camara)>Posotia (Vitex negundo)>Custard apple (Annona squamosa). While evaluating the effect of LC50 of each plant extracts on growth and development of looper caterpillar, it showed a considerable changes in developmental duration. The developmental duration varied between 3.66days to 4.83days, 4.83days to 6.66 days, 5.33days to 7.66days, 5.00days to 6.66days, and 7.33days to 9.33days for L-I, L-II, LIII, L-IV and LV respectively with the different LC50 of different plant extracts. Highest larval duration in all the instars of larva were shown by LC50 dose of Xanthium strumarium and lowest duration was shown by LC50 dose of Annona squamosa. Even it showed delay in pupal duration of treated larvae. Deformed adults were formed. They failed to oviposit and the adults could not survive a single day.ThesisItem Open Access Diversity of insect forager and effect of Xylocopa fenestrata pollination on sponge gourd (Luffa cylindrica)(AAU, Jorhat, 2021) Saikia, Irani; Deka, Mukul KumarThe present studies on “Diversity of insect forager and effect of Xylocopa fenestrata pollination on sponge gourd (Luffa cylindrica)” was carried out during the year 2020-21 with the objectives to enumerate the diversity of insect forager in sponge gourd (L. cylindrica) and to study the foraging behaviour and effect of X. fenestrata pollination on sponge gourd (L. cylindrica) in Horticulture Experimental Farm, Department of Horticulture, AAU, Jorhat. The results indicated that the insect forager complex of sponge gourd consists of 13 insect species which belong to the five insect orders such as Hymenoptera, Diptera, Lepidoptera, Hemiptera and Coleoptera. Among the insect pollinators Carpenter bee (Xylocopa fenestrata and Xylocopa leucothorax) was recorded to be maximum (23.66% and 8.50%) followed by Apis cerana (27.22%), A. dorsata (14.55%), Musca domestica (9.39%) and A. mellifira (7.50%). Besides these, other insect foragers found to visit as frequent visitors of sponge gourd flowers were Vespa cincta (3.04%), Apis mellifera (3.03%), and Coccinella septempunctata (2.36%). The foraging behaviour of X. fenestrata revealed that they began visiting sponge gourd blossoms early in the morning and stopped later in the evening. The highest frequency of floral visits was found to be 7.33±0.58 per minute between 1000-1200 hours while the lowest was 4.33±1.15 per minute between 1400-1700 hours. Likewise the pollen load per trip was determined to be 29.20±1.41 mg between 1000-1200 hours of the day with a minimum of 17.50±0.85 mg during 1400-1700 hours. Whereas, the maximum amount of time spent per flower was measured to be 26.16 ±1.011 seconds and minimum was 15.32±1.129 seconds. The maximum number of fruits per plant was obtained from XP3 (i.e. Xylocopa pollination @ five X. fenestrata nest on bamboo) treatment (19.03) followed by XP2 (i.e. Xylocopa pollination @ three X. fenestrata nest on bamboo) treatment (18.75) whereas in WXP (Without Xylocopa pollination) treatment only 6.45 numbers of fruits per plant was recorded. Similarly the XP3 treatment had the highest fruit set (36.59%), followed by XP2 treatment (36.11%), while the WXP treatment (12.60%) had the lowest fruit set. The XP3 treatment produced the highest yield (93.49±0.489 q/ha), followed by XP2 (93.18±0.655 q/ha), OP (82.34±0.503 q/ha), XP1 (62.45±0.517 q/ha), and WXP (23.90±0.950 q/ha) treatments.ThesisItem Open Access Bioformulation of entomopathogenic fungus against Helopeltis theivora Waterhouse (Hemiptera: Miridae)(AAU, Jorhat, 2022) Kaur, Priya; Das, PurnimaPathogenicity test of 5 strains or isolate of entomopathogens on adult Helopeltis theivora were carried out in the Physiology Laboratory, Department of Entomology, Assam Agricultural University, Jorhat during 2019-2021. Among the strains or isolate, Archips sp. isolate showed the best results at concentration 1x107 conidia/ml. The radial growth of Archips. sp isolatewas found to be 75.33 mm. At concentration 1x107 conidia/ml, the conidial density, germination and pathogenicity of Archips sp. isolate was 8.08x107 conidia/ml, 85.49% and 80%, respectively. Morphological characters of Archips sp. isolate were studied and its molecular characterization was carried out by using CP plant gDNA mini kit protocol and its accession no. was assigned as OM321438. While Archips sp. isolate when grown on liquid media supplemented with carbon, nitrogen and mineral sources (Glucose, Peptone and MgCl2), the medium supplemented with the mineral source- MgCl2 (0.75%) showed maximum conidial load (6.54x107 conidia/ml) and maximum germination (88.91%). Three talc-based formulations were prepared. One was prepared by using base material as harvested from PDB supplemented with 0.75% MgCl2, second with combination of all the nutrients (0.75% Glucose, 0.75% Peptone and 0.75% MgCl2) and third without nutrient. And among these formulations, all nutrients supplemented talc-based formulation showed maximum conidial density (11.52x107conidia/ml) and germination (90.06%). Also, in order to increase the virulence and efficacy of the prepared bio-formulation, two stickers- Tween-80 and Triton-X@ 0.01% and two spreader oils-coconut oil and mustard oil@ 0.025% were tested. It was found that the formulation incorporated with Tween-80@ 0.01% and coconut oil @0.025% had maximum conidial load(13.12x107 conidia/ml) and spore germination (95.49%). Three doses viz., 5, 10, 15 gm/L were tested on the adults of Helopeltis theivora. Among these doses, the dose of 15 gm/L showed the highest mortality (88%) at 9th DOT.
