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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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20211
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Subject: Plant Pathology × Author: Kaushik, Snata × End date: 2021 × Start date: 2021 × Thesis Type: M.Sc ×
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    ThesisItemOpen Access
    EVALUATION OF CITRUS CULTIVARS/GERMPLASMS OF ASSAM AGAINST CITRUS CANKER DISEASE
    (AAU, Jorhat, 2021) Kaushik, Snata; Nath, Bharat Ch.
    Evaluation of different citrus cultivars/germplasms against citrus canker disease in artificially inoculated conditions and their assessment for defense-related secondary metabolites, viz., total phenol, flavonoid, alkaloid content was attempted in the present study. For artificial inoculation, bacterial pathogen associated with diseased citrus canker leaf was isolated, purified, and further confirmed as Xanthomonas citri pv. citri by conducting morphological, cultural, gram staining, specific biochemical tests, and molecular characterization. Altogether thirty cultivars/ germplasms were tested for their degree of resistance against citrus canker (X citri pv. citri). All these cultivars/ germplasms showed significant differences in terms of percent disease severity and disease reaction. Out of thirty, eight cultivars/germplasms namely Jora tenga (14.67%), Bonjora (15.58%), Holong tenga (15.75%), Patijora (17.75%), Birajora (18.50%), Cleopatra mandarin (20.00%), Latipes (17.34%) and Ada jamir (20.18%) exhibited resistance response (R). Moderate degree of susceptibility (MS) was observed in fourteen cultivars/germplasms viz., Trifoliate orange (25.63%), Troyer citrange (26.87%), Rubidoux (30.37%), NRCC6 (36.58%), Bhutan orange (31.06%), Galgal (38.42%), Sopai (39.70%), Rangpur lime (43.30%), Soh bitara (30.27%) Sohmyndong (46.57%), Pummelo-1(31.34%), Pummelo-2 (28.38%), Pummelo-3(38.48%), Pummelo- 7(43.31%). Seven cultivars/germplasms namely Nainty jambhiri (52.56%), Australian orange (56.32%), Rough lemon (57.54%), Volkameriana (60.34%), White pummelo (61.64%), Acid lime (62.48%) and Grape fruit (70.63%) were categorized as susceptible types (S) while Assam lemon showed the highest degree of susceptibility (HS) against citrus cankerwith 78.14% disease severity. Further study on secondary metabolites revealed that total phenol, flavonoid, alkaloid content in citrus leaves differed greatly based on the cultivars/germplasms. The highest total phenol content (TPC) was found in one of the resistant germplasm Latipes (21.26 mg/g dry weight), while the lowest was recorded in susceptible cultivar Grapefruit (7.85 mg/g dry weight). Another resistant germplasm Jora tenga (6.47 mg/g dry weight) had the highest flavonoid content and the lowest was found in susceptible germplasm White pummelo (1.89 mg/g dry weight). Similarly, the highest alkaloid percentage was found in resistant germplasm Adajamir (10.52%) and the lowest was recorded in susceptible germplasm Volkameriana (2.30%). From the correlation analysis, three negative correlation coefficient was obtained viz.,P(rxy)= -0.861 for total phenol content, F(rxy)= -0.836 for flavonoid content and A(rxy)= -0.802 for alkaloid content.