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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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20201
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Subject: Agricultural Entomology × Author: Ahmed, Shabrin Sultana ×
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    ThesisItemOpen Access
    ECOLOGICAL AND BIOCHEMICAL BASIS OF RESISTANCE AGAINST STEM BORER AND LEAF FOLDER OF AROMATIC RICE
    (2020-01) Ahmed, Shabrin Sultana; Saikia, D. K.
    The present investigation was carried out at Instructional Cum Research farm, Assam Agricultural University, Jorhat during kharif 2017 and 2018, respectively to generate a comprehensive information about screening of different aromatic rice varieties along with to determine the relationship between physio-morphic as well as biochemical properties of aromatic rice varieties against the incidence of stem borer and leaf folder and also to study diversity of major insect pests and their natural enemies in rice ecosystem. Varietal screening of eleven aromatic rice varieties revealed that during kharif 2017 and 2018, none of the varieties showed resistance to stem borer in active tillering stage,whereas Kola Joha (12.33%), Sofguti Joha (12.75%), Boga Joha (13.37%), Maniki Joha (13.70%), Keteki Joha(15.67%), Ronga Joha (17.60%) Kon Joha (18.38%), and Krishna Joha (20.37%) showed moderately resistance during vegetative stage.The variety Kon Joha (4.79%) and Maniki Joha(2.40%), however showed resistance during reproductive stage.In case of damaged leaf due to leaf folder infestation, almost all the aromatic rice varieties were proved to be resistant during the study period except check variety “Jaya”.Different physio-morphic characters of rice plant against leaf folder damage recorded significant positive correlation with width of leaf blade (r = 0.821** and r = 0.865**),whereas significant negative impact was with plant height (r = -0.939** and r = -0.778**).The per cent dead heart (DH) caused by stem borer exhibited significant positive correlation with stem diameter (r = 0.829** and r = 0.816**),but it showed significant negative correlation with plant height (r = -0.732** and r = -0.784**), number of leaves (r = -0.962** and r = -0.891**), number of trichomes (r = -0.860** and r = -0.870**), number of tillers (r = -0.806** and r = -0.739**),number of grains per panicle(r = -0.688* and r = -0.771*) and thousand grain weight (r = -0.650* and r = -0.570NS ), respectively. In case of per cent WEH, width of leaf blade(r = 0.608* and r =0 .678) had positive impact,but plant height (r = -0.606* and r = -0.598*)and number of leaves ( r = - 0 .655* and r = - 0.577*) showed significant negative relationship. Total of 6 species of odonates, 5 species of spider, 2 species of coccinellids, 3 species of lepidopteran, 1(one) species of each hemipteran, homopteran and coleopteran insect were recorded during the investigation period. As regards to diversity index, Sofguti Joha (1.59) showed the highest diversity index and Kola Joha (0.90) showed the highest species richness at vegetative stage, whereas the highest evenness (0.99) was found in Boga Joha at harvesting stage. In case of natural enemy complex, the highest diversity index of 2.50 and species richness (3.05) were recorded in Boga Joha at vegetative stage and the highest species evenness (0.99) was observed in Kola Joha at harvesting stage. Different sampling methods revealed the highest abundance of S. innotata (16.47%) in Boga Joha, Cnaphalocrocis medinalis (12.50%) and Dicladispa armigera (7.66%) in Sofguti Joha,whereas Leptocorisa acuta (24.61%) was appeared as the highest in Maniki Joha and Nephotettix nigropictus (50.0%) in Sofguti Joha. A total of 5 species of spider were recorded during the investigation period.The variety Maniki Joha supported more abundance of Oxyopes javanus (11.04%), Pardosa pseudoannulata (14.93%) and Tetragnatha maxillosa (9.74%), whereas Argiope anasuja (7.56%) in Boga Joha and Neoscona theisi (6.38%) in Sofguti Joha, respectively.The sub-order of odonata, viz., Zygoptera and Anisoptera had equal numbers of species (3 species each) during 2018.Data collected through different sampling methods showed the highest abundance of Brachythemis contaminate (14.89%), Crocothemis Servilia Servilia (10.11%) in Sofguti Joha,, Diplacodes nebulosa (7.30%) in Kola Joha, Aciagrion hisopa (12.98%) and Agriocnemis pygmaea (11.68%) in Maniki Joha and Agriocnemis pieris (10.27%)in Boga Joha. Two species of predators under order coleoptera viz., Coccinella tranversalis (F.), Micraspis discolor (F.) were found to be observed during the period of investigation. However, the highest abundance of C. transversalis was found in Kola Joha with 9.44 per cent and M. discolor with 8.10 per cent in Boga Joha. Among the tested biochemical parameters, Phenol (r = -0.985** and r = -0.834**), Ortho-dihydroxy phenol (r = -0.963** and r = -0.829**), Tannin (r = - 0.837** and r = 0.621*), Peroxidase (r = -0.937** and r = 0.871**) and Phenylalanine Ammonia Lyase ( r = -0.972** and r = -0.622*) exhibited negative significant impact with stem borer and leaf folder infestation. However, protein (r = 0.946**) showed positive significant correlation only with stem borer infestation. In terms of aroma, both Kola Joha and Koni Joha performed excellent in aroma having a score of 5 followed by Maniki Joha, Boga Joha and Bokul Joha with a score of 3.5-4. However, Keteki Joha, Krishna Joha, Kon Joha and Sofguti Joha produced medium aroma with a score of 2.5-3 and Ronga Joha produced very low aroma (score 2).As regards to yield, the highest yield was attributed by Kon Joha (2535.35 kg/ha) and the lowest yield of 1366.31kg/ha was obtained in Tulsi Bhog Joha.