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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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2018 - 20197
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Subject: Nematology × End date: 2019 × Start date: 2018 ×
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Now showing 1 - 7 of 7
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    ThesisItemOpen Access
    ISOLATION AND FORMULATION OF ENTOMOPATHOGENIC NEMATODES
    (AAU, Jorhat, 2018) GEORGE, JISNA; Devi, Gitanjali
    An experiment entitled “Isolation and formulation of Entomopathogenic nematodes” was conducted in the laboratory of Department of Nematology, Assam Agricultural University, Jorhat. A random survey was conducted for the natural occurrence of EPNs during 2016-17 from vegetable growing areas. A total of two hundred soil samples were collected from ICR Farm, Experimental farm of Department of Horticulture and Hostel areas, AAU, Jorhat and Allengmora, Jorhat. Survey data revealed that out of 200 soil samples, twelve samples were positive for EPNs with six samples containing Oscheius (3%), five samples containing Heterorhabditis (2.5%) and one sample containing Steinernema (0.5%). Oscheius isolates were designated as EPN-O-J-1, EPN-O-J-2, EPN-O-J-3 and Heterorhabditid isolate designated as EPN-H-J-1, EPN-H-J-2 were found from rhizosphere of chilli, cowpea, bhendi, brinjal and chilli respectively from ICR Farm, AAU, Jorhat. Another isolate of Oscheius designated as EPN-O-J-4, EPN-O-J-5 and Heterorhabditid isolate designated as EPN-H-J-3, EPN-H-J-4, EPN-H-J-5 were found from rhizosphere of bhendi, chilli, cucumber and bhendi respectively from Hostel areas, AAU, Jorhat. One Oscheius isolate designated as EPN-O-J-6 was found from rhizosphere of pumpkin and one steinernematid isolate designated as EPN-S-J-1 was found from rhizosphere of ivy gourd from Allengmora, Jorhat. Morphological and morphometrical characters were used in the identification of nematode isolates. The identified species were Heterorhabditis bacteriophora, Oscheius rugaoensis and Steinernema kushidai. O. rugaoensis was the predominant species followed by H. bacteriophora and S. kushidai. Nematode survival within each formulation was determined after one week up to 6th week. Formulations were stored at 5°C and 300C. Storage stability in all formulations decreased during the storage period. Per cent survival of H. bacteriophora infective juveniles (IJs) was 99.80% in alginate gel, and 98.36% in sawdust during 6th week of storage at 50C, whereas per cent survival was less (98.90% and 98.36% respectively) at 300C up to 6th week of storage. O. rugaoensis showed 98.30% survival in sawdust and 97.30% survival in alginate gel formulation at 50C, whereas per cent survival was less (95.50% and 93.76%, respectively). Per cent survival of S. kushidai infective juveniles (IJs) was 95.56% in alginate gel, and 93.73% in sawdust, respectively during 6th week of storage at 50C, whereas per cent survival was less (93.80% and 91.53%, respectively) at 300C. The quality control measure implemented to determine the virulence of formulated nematodes, using the percentage mortality of G. mellonella as an indicator, was effective. Per cent infectivity to G. mellonella larva was more in H. bacteriophora (93.66%) in alginate gel formulation followed by O. rugaoensis (93.33%) in sawdust formulation and S. kushidai (91.00%) in alginate gel formulation in both bioassay.
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    ThesisItemOpen Access
    Pathogenicity and Management of Root-knot Nematode (Meloidogyne incognita) on Ivy gourd (Coccinia indica L.)
    (AAU, Jorhat, 2018) Sonowal, Bidisha; Mahanta, B.
    In the present study on pathogenicity of Meloidogyne incognita on Ivy gourd showed that there was a progressive decrease in the growth of Ivy gourd plants as the inoculum level of Meloidogyne incognita increased. An initial inoculum level of 100 juveniles per pot caused significant reduction in plant height, shoot weight and root weight and proved to be pathogenic to Ivy gourd plants. The reproductive rate of nematode was maximum at the initial inoculum level of 10 juveniles per pot and minimum at the highest inoculum level of 10,000 juveniles per pot. Studies on the efficacy of Glomus fasciculatum, Org-Trichojal, vermicompost and carbofuran 3G in the management of Meloidogyne incognita on Ivy gourd under field condition showed that all the treatments were effective in increasing plant growth parameters and yield of Ivy gourd. All the treatments significantly decreased root-knot index and final nematode population in soil. The treatment with Glomus fasciculatum @ 300 spores/ m2 + Org-Trichojal @ 1 l/ha + vermicompost @ 1.25 t/ha was found to be effective in increasing the plant growth parameters and yield of Ivy gourd per plot. The treatment with carbofuran 3G @ 1 kg a.i/ha was found to be effective in suppressing the root-knot index and final nematode population in soil.
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    ThesisItemOpen Access
    HISTOPATHOLOGICAL AND BIOCHEMICAL CHANGES IN TRADITIONAL RICE CULTIVARS DUE TO RICE ROOT-KNOT NEMATODE, Meloidogyne graminicola
    (2019-11) Gogoi, Priyanka; Borgohain, N.
    An investigation was carried out to observe the histopathological and biochemical changes in traditional rice cultivars of Assam. A total of 35 rice cultivars were screened against rice root-knot nematode Meloidogyne graminicola. Out of these, eight cultivars viz., Bongal ahu, Malbhog ahu, Naga ahu, Bahadur sub-1, Shraboni, Disang, Kolong and Jaymati were found to be resistant whereas five cultivars viz., Ahu joha, Bhogali bora, Aghoni bora, Ranjit sub-1 and Kanaklata found to be moderately resistant. The two traditional cultivars viz., Sambha mashuri and Kanaklata were found to be susceptible and the remaining 20 cultivars were found to be highly susceptible. Histopathological studies of resistant cultivars revealed that there is no establishment of feeding cells with hypersensitive like reaction in pericycle areas, whereas in susceptible cultivars multinucleate giant cells with dense cytoplasm and large number of vacuole were observed. The hypertrophied and hyperplasia cell were observed surrounding the body of the nematodes and the giant cells were observed at little distance to the nematode head. While evaluating the chlorophyll content, the highest chlorophyll was found in the cultivar Naga ahu i.e 0.040 μg/ml and lowest in Dhanshree. Similarly lowest phenolic content (0.0004 mg/ml) was recorded in the cultivar Sambha mashuri and the highest in Disang and Jaymati (0.00041 mg/ml). The enzymatic activity of PPO was maximum (0.294 mg/min) in cultivar Jaymati and minimum (0.140 mg/min) in Sambha mashuri at 3min time interval. The activity of PAL was highest in the Malbhog ahu (1.57 m-1 mg-1 protein) followed by Bahadur sub-1 (1.51 m-1 mg-1 protein) and minimum in Sambha mashuri (0.16 m-1 mg-1 protein).
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    ThesisItemOpen Access
    Evaluation of Antagonistic Potential of Certain Plants Against Root-knot Nematode, Meloidogyne incognita
    (AAU, Jorhat, 2019-07) Goswami, Kasturi; Gogoi, Bina B.
    In the present investigation, an effort was made to evaluate antagonistic potential of some plants against root-knot nematode Meloidogyne incognita. In a screening trial, nine different antagonistic plants viz. Marigold, Garlic, Mustard, Chrysanthemum, Strawberry, Periwinkle, Sesame, Broccoli and Castor were tested against M. incognita. All these antagonistic plants produce very low number of galls, resulting low root-knot index compared to the susceptible control. Among these plants, Marigold, Periwinkle, Garlic were found to be in the resistant category, while Broccoli was found to be moderately resistant. In a root-knot infested field, these four plants were intercropped with root-knot susceptible tomato to see the antagonistic effect of these plants on root-knot nematode. All the treatments with these four intercrops were found to be effective in reducing number of galls, egg masses and final nematode population in soil subsequently increasing plant growth parameters. The treatment with Periwinkle was found to be most effective in increasing the growth parameters viz. shoot length, shoot weight, root length and root weight of Tomato with corresponding decrease in number of galls, egg masses, final nematode population in soil. The increase in yield of Tomato per ha was maximum when tomato was intercropped with periwinkle, followed by Marigold.
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    ThesisItemOpen Access
    MANAGEMENT OF ROOT KNOT NEMATODE (Meloidogyne incognita) IN TOMATO BY BACTERIAL BIOAGENT
    (AAU, Jorhat, 2019-09) Nyodu, Karter; Das, Debanand
    Investigations were carried out to evaluate the efficacy of bacterial bioagents viz., Bacillus subtilis, Bacillus megaterium, Bacillus pumilus and Pseudomonas fluorescens as seed as well as soil treatment against root knot nematode, Meloidogyne incognita on tomato (var. Pusa Ruby). Seed treatment experiment was conducted with thirteen treatments viz., T1: B. subtilis (1×109cfu/gm of talc formulation) @ 10gm/kg of seed, T2: B. subtilis (1×109cfu/gm of talc formulation) @ 20gm/kg of seed; T3: B. subtilis (1×109 cfu/gm of vermi formulation) @ 10 gm/kg of seed; T4: B. subtilis (1×109 cfu/gm of vermi formulation @ 20 gm/kg of seed; T5: B. pumilus (1×109cfu/gm of talc formulation) @ 10gm/kg of seed; T6: B. pumilus (1×109cfu/gm of talc formulation) @ 20gm/kg of seed; T7: B. megaterium (1×109cfu/gm of talc formulation) @ 10gm/kg of seed; T8: B. megaterium (1×109cfu/gm of talc formulation) @ 20gm/kg of seed; T9: B. megaterium (1×109 cfu/gm of vermi formulation) @10gm/kg of seed; T10: B. megaterium (1×109 cfu/gm of vermi formulation) @ 20gm/kg of seed; T11: Pseudomonas fluorescens (1×109cfu/gm of talc formulation) @ 10gm/kg of seed; T12: P. fluorescense (1×109cfu/gm of talc formulation) @20/kg of seed and T13: untreated control. Results revealed that there were a significant increase in plant growth parameters and significant decrease in galls, eggmass and soil nematode population in all treatments over untreated control. However, seed treated with Pseudomonas fluorescens @ 20g/kg seed recorded the best result in increasing the plant growth parameters of tomato and reducing the root knot nematode multiplication followed by Bacillus subtilis (vermi formulation) @ 20g/kg seed. Pot experiment was conducted to evaluate the efficacy of bacterial bioagents as soil application with thirteen treatments viz., T1: Bacillus subtilis (1×109cfu/gm of talc formulation) @ 2%(w/w); T2: B. subtilis (1×109cfu/gm of talc formulation) @ 3%(w/w); T3: B. subtilis (1×109 cfu/gm of vermi formulation) @ 2%(w/w); T4: B. subtilis (1×109 cfu/gm of vermi formulation @ 3% (w/w); T5: B. pumilus (1×109cfu/gm of talc formulation) @ 2%(w/w); T6: B. pumilus (1×109cfu/gm of talc formulation) @ 2% (w/w); T7: B. megaterium (1×109cfu/gm of talc formulation) @ 3% (w/w); T8: B. megaterium (1×109cfu/gm of talc formulation) @ 2% (w/w); T9: B. megaterium (1×109 cfu/gm of vermi formulation) @ 3% (w/w); T10: B. megaterium (1×109 cfu/gm of vermin formulation) @ 3% (w/w); T11: Pseudomonas fluorescens (1×109cfu/gm of talc formulation) @ 2% (w/w); T12: Pseudomonas fluorescens (1×109cfu/gm of talc formulation) @3% (w/w) and T13: Untreated control; The result revealed that all the treatments significantly increased plant growth parameters and significantly decreased gall per root system, eggmass per root system and final root knot nematode population in soil over untreated control. However, maximum plant growth parameters and reduction in root knot nematode multiplication were recorded in soil treated with Pseudomonas fluorescens @ 3% (w/w) followed by Bacillus subtilis (vermi formulation) @ 3% (w/w) whereas minimum was recorded in untreated control
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    ThesisItemOpen Access
    EFFICACY OF ENTOMOPATHOGENIC NEMATODES (EPNs) AGAINST MAJOR INSECT PESTS OF TEA
    (AAU, Jorhat, 2019-07) BHARATH, AMURI; Devi, Gitanjali
    A total 200 soil samples were collected from tea plantation areas of district, Jorhat, Assam and were assessed for entomopathogenic nematodes using the Galleria baiting technique. Out of 200 soil samples, EPNs were found in 2 soil samples with 1% frequency of occurrence. One isolate of Oscheius sp. (0.5%), was isolated from Experimental farm for plantation crops, Section-4, 10, 19 AAU, Jorhat and another Heterorhabditis sp. (0.5%) was isolated from Chetiagoan, Jorhat. Morphological and morphometrical characters were used in the identification of nematode isolates. The identified species were Heterorhabditis bacteriophora, and Oscheius chongmingensis. In infectivity study, indigenous isolates of EPNs, Heterorhabditis bacteriophora and Oscheius chongmingensis tested in the laboratory bioassay, caused mortality of tea mosquito bug, Helopeltis theivora and bunch caterpillar,Andraca bipunctata. Fifty, 60 and 70 per cent mortality of Helopeltis theivora by H. bacteriophora at 150 IJs/insect was observed at 48 h, 72 h and 96h respectively. With the increase in the exposure period to 96 h, H. bacteriophora could induce up to 90% mortality of the tested insect at the dose of 250 IJs. Similarly, mortality of Helopeltis theivora increased with increase in the dosage of O. chongmingensis and recorded 50, 60 and 70 per cent mortality at 200 IJs/insect at 48 h, 72 h and 96h. Bioassay of H. bacteriophora and O. chongmingensis against the 3rd instar larvae of Andraca bipunctata indicated that at 250 IJs/larva recorded 70 and 60% mortality in 48 hours of exposure, while 100 and 90% mortality of Andraca bipunctata was recorded at 96h. H. bacteriophora was more pathogenic than Oscheius chongmingensis against Helopeltis theivora and Andraca bipunctata based on LD50 values at 48 h, 72 h and 96 h.
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    ThesisItemOpen Access
    MECHANISM OF LANTANA CAMARA LEAF EXTRACTS IN THE MANAGEMENT OF MELOIDOGYNE INCOGNITA ON TOMATO
    (AAU, Jorhat, 2019-07) Bordoloi, Kankana; Bhagawati, B.
    An experiment was carried out on the mechanism of Lantana camara leaf extract in the management of Meloidogyne incognita on tomato. For this, leaf extract of L. camara (25gm/75ml w/v) were evaluated at 25, 50, 75 and 100 percent concentration through egg hatch inhibition and larval mortality test. The result of the in-vitro efficacy test showed that maximum egg hatch inhibition of M.incognita was recorded in the 100 percent concentration of L. camara leaf extract where as minimum was recorded in the 25percnet concentration after 7 days of exposure time. The maximum mortality of M. incognita J2was recorded in the 100 per cent concentration of L. camara leaf extract where as minimum was recorded in the 25 per cent concentration after 24, 48, 72 and 96 hours of exposure time. No mortality was recorded in the control treatment i.e. sterile distilled water. It was observed that there was an increasing trend in the mortality of J2 with increase in the concentration and time of exposure. Similarly, egg hatch inhibition was also found to be more with increase in the concentration. A pot experiment was conducted to explore the biochemical mechanism of leaf extracts of L. camara in the management of M. incognita on tomato. For this the activity of defence related enzymes viz., peroxidase (PO), polyphenoloxidase (PPO) and total phenol content were observed at 25,50,75 and 100 percent concentration of L. camara leaf extract after 35and 45 DAI of M .incognita in tomato. Among the different concentrations, highest activity of peroxidase (PO), polyphenoloxidase (PPO) and total phenol content was observed at 100 percent concentration while the minimum activity was recorded in the 25 percent concentration both after 35and 45 DAI. However, maximum activity of the biochemical compounds was recorded at 35 DAI while the same declined at45 DAI. The lower concentration of L. camara leaf extract viz., 25 and 50 percent showed stimulatory effect on plant growth parameter whereas higher concentrations viz., 75 and 100 percent concentration of L. camara leaf extract showed inhibitory effect on plant growth. The maximum plant growth parameter like shoot height, shoot weight (fresh) and root length and root weight (fresh), dry shoot weight were recorded in the 50 percent concentration of L. camara leaf extract where as the minimum was recorded in the nematode alone treatment. The minimum nematode multiplication like number of galls, number of eggmasses and final nematode population in soil were recorded in the 100 percent concentration of L. camara leaf extract followed by 75, 50 and 25 percent concentration.