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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 TAPPING OF CARBON DIOXIDE IN RICE ECOSYSTEM THROUGH AZOLLA CULTIVATION(AAU, Jorhat, 2017-07) Khwairakpam, Rowndel; Das, RanjanThe present investigation was carried out in the stress physiology laboratory under fully automated bioreactor where tapping of CO2 and external injection regulation CO2 facility were available. To understand the assimilation and N accumulation in Azolla-Rice ecosystem in response elevated CO2 possible interactions of CO2 and Azolla on the growth and yield of rice investigation was conducted during the kharif season of 2014 and 2015.The studies revealed that there was variable response of photosynthetic parameters which lead to impact on carbon sequestration potential as well as change in O2 evolution under varying levels of CO2 environment under rice-Azolla ecosystem. In case of fluorescence and related parameters, there was deviation from the normal range as the CO2 concentration increased, however these deviations were minimized in presence of Azolla. These were also same in case of ETR, NPQ, PQ, ф PSII etc. Photosynthetic and its related parameters viz. gs, Ci, T, etc. were found to be related to stomatal density and size. These factors ultimately affected plant growth which was translated as yield. Elevated (500 ppm) CO2 with Azolla has a greater potential for C sequestration, while soil organic carbon enhancement helped increase crop productivity and sustainability which was evident from higher yield and yield attributing parameters. Soil microbial population with higher C: N ratio was recorded under elevated CO2 with rice-Azolla ecosystem. There have been increasing concerns regarding the role of soil microbial population in biological stabilization of SOC in agricultural soils because change in the soil microbial population within rhizo-spheres with changes in organic matter input. Significant reduction of NPK was recorded due to elevated CO2, however; reduction rate was variable with Azolla when compared with without Azolla and ambient. Conversion of inorganic nitrogen was significantly reduced in elevated CO2 however there was amelioration affect under 500 ppm CO2 with Azolla due to significant increase in key enzymes such NR, NiR and GS syntheses activity. CO2 enrichment decreased the N concentration in rice without any change in the C content, leading to an increase in C:N ratio However variability among systems also recorded. This study: (1) depicts the changes in microbial population and fungal predominance; (2) infers a biological stabilizing mechanism behind the C sequestration which includes physical-chemical stabilization as the major controlling processes leading to variation of yield. Azolla has enormous potential to sequester of atmospheric CO2 due to its rapid growth in freshwater without the need for a soil-based nitrogen source. Azolla is a novel opportunity to expand and diversify the supply of fertilizers and production of rice fields vis a vis tapping the CO2 and enhancing the O2 evolution system under changed environmental conditions.ThesisItem Open Access PHYSIOLOGICAL CHARACTERIZATION OF SOME WHEAT GENOTYPES FOR HIGHER NITROGEN USE EFFICIENCY AND YIELD POTENTIAL IN ASSAM(AAU, Jorhat, 2017-09) Chack, Sonbeer; Bharali, B.Wheat is one of the most important cereal crops globally, and is a staple food for about one-third of the world’s population (Hussain et al., 2002). Nitrogen is the most important yield-limiting nutrient for crop production in the world (Huber and Thompson, 2007). Two field experiments were conducted for two consecutive years near Stress Physiology Laboratory, Department of Crop Physiology, Assam Agricultural University. The main objective of the study was to characterise some wheat genotypes (collected from East Zone of India) physiologically for higher nitrogen use efficiency (NUE) and yield potential in Assam. In the first year experiment (November, 2014-April, 2015): Nitrogen @ 0, 50, 100, 150 kg ha-1 (as Urea) in the form of granules @ 50% of N as basal with the whole recommended doses of P (as Single super phosphate) and K (as Muriate of potash), and the rest 50% Urea were applied at maximum tillering stage. In the second year experiment (November, 2015-April, 2016), Nitrogen @ 0, 500, 1000, 1500 ppm (equivalent to granules in kg ha-1) were applied as foliar spray at the maximum tillering stage (once in a week for two weeks) of the crop. In the first year experiment, the varieties having the higher NUE in leaves were Wheat 231 (11.36%)> HP 1744 (8.58%)> Pusa Gold (8.42%), and higher NUE in seed were Wheat 231 (19.41%)> HP 1744 (10.01%)> Pusa Gold (9.29%)> PBW 343 (8.27%)> HD 2967 (6.08%). The physiological parameters contributing to the higher NUE in the varieties were maximum Leaf area in Wheat 231(16.81, 17.55 cm2 plant-1)> HD 2967 (15.11, 16.98 cm2 plant-1) at maximum tillering and PI stages respectively. The maximum leaf number was observed in wheat 231 (23.27)> HP 1744 (21.53)> PBW 343 (19.43) under the highest dose of N i.e. 150 kg ha-1 at panicle initiation stage. The other physiological parameters viz. root length of Wheat 231 (12.77 cm)>Pusa Gold (12.57 cm), root volume of Wheat 231 (10.31 cc)> PBW 343 (8.43 cc), and shoot dry weight of Wheat 231 (1.66 g)> HP 1744 (1.55 g) were responsive to augment NUE in the wheat varieties. The variety Wheat 231 (36.18, 34.26)> HP 1744 (33.19, 33.60) showed the highest NR activity (nmol NO2- g-1 fw of leaf) at both Maximum tillering and PI stages. Wheat 231 also exhibited higher N contents in leaf (0.41%) at PI stage, in grain (0.61%), and in leaf (0.37%) at harvest. The yield and yield attributes for higher NUE in the variety Wheat 231 were number of seed spike-1 (48.73), spike length (12.72 cm), spike weight (4.01 g), test weight (45.67), economical yield (3.02 t ha-1) and harvest index (47.32%). Nitrogen @ 150 kg ha-1 imparted higher NUE in leaves (12.48%) and grain (15.79%). In this contest, the physiological & biochemical parameters were leaf number (22.45), leaf area (18.30 cm2), root volume (8.41cc), NR activity (34.08 nmol NO2- g-1 fw of leaf) at PI stage, and starch content in leaf (271.05 mg g-1 d.w.) at maximum tillering stage, total N uptake (37.50%) and N content in seed & leaf (0.46%, 0.38%) at harvest as compared to values in controlled one. In the second year experiment, the varieties having the higher NUE in leaves were of Wheat 231 (10.90%)> HP 1744 (8.15%); and in case of seed, it was in Wheat 231 (18.74%) only. The physiological parameters contributing to the higher NUE in the variety Wheat 231 were: maximum leaf area (15.29 cm2 plant-1) at PI stage; root length (14.66 cm) at PI stage, NR activity (37.40 nmol NO2- g-1 fw hr-1) at maximum tillering stage, nitrogen content in leaf (0.456%) at PI stage and starch content in leaf (221.20, 241.22 mg g-1 d.w) at both maximum tillering and PI stages. The yield and yield attributes for higher NUE in the variety Wheat 231 were number of seed spike-1 (46.39), spike length (12.03 cm), test weight (44.00 g), economical yield (2.76 t ha-1) and harvest index (47.07%). The N dose @ 1500 ppm triggered higher NUE in leaves (12.07%) and grains (15.61%) at harvest. In this case, the other physiological & biochemical parameters contributing the higher NUE were leaf area (16.05 cm2), root length (14.39 cm), NR activity (19.08-37.69 nmol NO2- g-1 fw hr-1), N content in seed & leaf (0.493% & 0.394%) at harvest and nitrogen harvest index (0.56%) as compared to values in the controlled one. Overall, in the experiment 1, the variety Wheat 231 possessed the highest score (12) followed by PBW 343 (3)> Pusa Gold (1), and the variety HP 1744 & HD 2967 obtained zero score at harvest. In the second year, too, Wheat 231 (11) scored the highest followed by PBW 343 (3)> Pusa Gold (2)> HP 1744 (1), and the variety HD 2967 obtained zero score at harvest. Thus, it could be concluded that Wheat 231 emerged as the most physiologically efficient variety in the experiments. This variety possesses the adaptive traits, especially the higher NUE, yield and its attributes. Further, N-dose response studies revealed that N @ 150 kg ha-1 (as granule) or N @ 1500 ppm (as foliar spray) in the form of Urea was the most effective in augmenting the NUE and its related physiological indices including economic yield in wheat crop in Assam.ThesisItem Open Access ASSESSMENT OF CROP CONDITION UNDER ABIOTIC STRESS USING REMOTE SENSING TECHNIQUE IN UPLAND RICE CROP(AAU, Jorhat, 2017-09) Goswami, Jonali; Das, RanjanThe rise of CO2 (600 µmol mol-1 CO2 by the middle of 21st century) will effectively influence the productivity of crop plants. Again nitrogen is a limiting nutrient in most of the agricultural soils. In the present investigation, the responses of local genotypes of rice were studied in Carbondioxide Temperature Gradient Tunnel (CTGT) to simulate elevated CO2 concentration and temperature. Similarly, pot experiment was done at varying levels of nitrogen fertilization. The results revealed that CTGT II had a greater impact on various morpho-physiological parameters and showed a declining trend indicating the deleterious effect of high temperature, at a higher CO2 and temperature in CTGT III, but, some parameters viz. stomatal conductance and transpiration rate were significantly reduced at CTGT II. From the above experiment, it is evident that some degree of tolerance exhibited against high temperature stress which could be attributed to higher accumulation of carbohydrates, proline, adjustment of anatomical features, water status, better defense mechanism particularly in the genotype Inglongkiri followed by Banglami as compared to IET 22238 and Bash under elevated carbondioxide and temperature conditions. Similarly, nitrogenous fertilizer application had a statistically significant effect on yield components of rice genotypes. There was an increase in yield components with increase in each successive level of nitrogen fertilizers. Enhancement of yield components under high nitrogen levels might be attributed to vigorous and healthy growth, higher photosynthetic pigments, improved water relations and the formation of the membrane system of chloroplasts. Among rice genotypes Inglongkiri recorded significantly higher yield components at low nitrogen levels as compared to the Banglami, IET22238 and Bash. Further, it was revealed that hyperspectral remote sensing could effectively be used for detection of varietal performance, nutrient content and other biochemical parameters of the crop. It was observed that few specific bands were sensitive to chlorophyll (704,803 nm), protein (1514nm), nitrogen (2060, 2300nm), Fluorescence (730nm). Apart from specific bands, indices like NDVI, PSSRa, PSRI, FRI were highly correlated to different parameters of the crop. It is observed from regression analysis that yield can be estimated as function of different spectral indices with a R square value more the 0.7 under both the conditions at a statistical significance with 95% confidence level. A GUI has been developed for display and retrieval of information for the target plants which aided in generation of spectral data base to discriminate spectral behavior of commonly grown genotypes of rice in this region.ThesisItem Open Access Carbon sequestration through bamboo plantation(AAU, Jorhat, 2015) Choudhury, Hemendra; Kalita, P.A study was conducted during 2011-13 in i) inside open top chambers (OTC) with four CO2 concentrations (control, 380, 550 and 750 ppm), ii) in the experimental bamboo field of B N College of Agriculture, AAU Biswanth Chariali (OST) and iii) in farmer’s field of Biswanath Chariali (OFT) to assess the carbon sequestration potential of four bamboo species viz. S1: Bambusa tulda, S2: B. nutans, S3: B. balcooa and S4: Dendrocalamus hamiltonii. The result revealed that with the increase in CO2 concentration from 380 ppm to 750 ppm the seedling height, seedling girth, number of shoot/seedling, phyllochron, leaf number and leaf area/seedling, weight of leaf, branch, main stem, rhizome and whole seedling, specific leaf weight, relative leaf water content, stomatal frequency, stomatal index, stomatal pore area, chlorophyll content, chlorophyll stability index, carotenoid content, Rubisco activity, photosynthetic rate, content of starch, reducing and nonreducing sugar total sugar, non structural carbohydrate and soluble protein of bamboo seedlings showed better results in all four bamboo species tested. Being C3 plant the bamboo seedlings increase the rate of photosynthesis at elevated CO2 concentration and thereby register the higher values of growth parameters. At OST and OFT the S4 maintained the highest average culm height, DBH of culm, cum thickness, RLWC, stomatal frequency, stomatal index, percent pore area of leaf, LAI, Rubisco activity, rate of photosynthesis, content of chlorophyll, carotenoid, soluble protein, starch, total sugar in leaf and content of C, N, P, K in leaf branch, culm and in rhizome. In contrast the S1 registered the poorest performances among all four bamboo species. The S4 produced the highest (260.25 ton/ha) total dry biomass with the highest leaf (7.16 ton/ha), branch (24.83 ton/ha), culm (207.64 ton/ha) and rhizome (10.98 ton/ha) biomass while S1 produced the lowest (212.10 ton/ha) total dry biomass with lowest leaf (3.88 ton/ha), branch (20.36 ton/ha), culm (171.84 ton/ha) and rhizome (8.86 ton/ha) biomass. S4 sequestered the highest total carbon (118.72 ton/ha) followed by S3 (110.00 ton/ha) and S1 sequestered the lowest total carbon (93.52 ton/ha) at 5th year of plantation. The S4 also produced the highest average leaf (1.35 kg), sheath (0.90 kg) and branch (0.12 kg) litter per clump. The bamboo plantation also enriched the soil with organic carbon, available N, P, and K up to 50 cm soil depth. The present study therefore, concludes that bamboo being an efficient carbon sequesterer could contribute tremendously to mitigate the climate change, besides providing other economic and social contributions.ThesisItem Open Access Interactive effect of elevated carbondioxide and temperature on physiological characterisation of bhoot jolokia (Capsicum chinense Jacq.)(AAU, Jorhat, 2015) Das, Sangita; Das, RanjanA study was conducted during 2012-2014 in Carbondioxide Temperature Gradient Tunnels (CTGTs) and in ambient condition to assess the interaction effect of elevated carbondioxide and temperature in two cultivars of Capsicum chinense Jacq. The treatments consisted of field (ambient CO2 and ambient temperature), CTGT I (380 ppm CO2 and ambient temperature), CTGT II (550 ppm CO2 with ambient temp. + 20 C elevation) and CTGT III (750 ppm CO2 with ambient temp. + 40C elevation). The elevation of temperature as compared to ambient was maintained from flower bud initiation to maturity stage. The results revealed that CTGT II had a greater impact on the various morpho physiological parameters viz. plant height, leaf number, branch number, plant spread, leaf area index, leaf area duration, specific leaf weight, root: shoot ratio, relative leaf water content, water potential, osmotic potential, C: N ratio, photosynthesis and chlorophyll stability index. However, at a higher CO2 and temperature in CTGT III, most of the above parameters showed a declining trend indicating the deleterious effect of high temperature. But, some parameters viz. senescence index, stomatal conductance and transpiration rate were significantly reduced at CTGT II. The phyllochron index was significantly reduced in both the elevated CO2 and temperature treatments. Similarly in biochemical parameters viz. accumulation of sugars, starch, total non structural carbohydrate, proline, antioxidant enzymes, capsaicin content showed a significantly higher value in both CTGTs as compared to ambient condition. A decline in pigments content of leaves such as chlorophyll and carotenoid were observed under both the CTGTs. A better status of membrane was recorded at CTGT II as compared to CTGT III and ambient condition in terms of lower activity of lipoxygenase, MDA (Lipid peroxidation) and H2O2 content and relative stress injury; hence a higher value of membrane stability index was recorded in CTGT-II. An enhancement in flowering was observed in both the elevated CO2 and temperature than ambient condition. Anatomical studies revealed better pollen characters; stem xylem and phloem status in CTGT II when compared to CTGT III. RT PCR data showed up-regulation of some genes viz. photosynthetic genes, antioxidant genes and capsaicin synthase gene under both the CTGTs. Better yield attributing parameters were recorded in CTGT II as compared to CTGT III and other treatments, which could be correlated to a higher percent of fruit dropping in CTGT III. Reduction due to high temperature in terms of above parameters was ameliorated under CTGT II. From the above experiment, it is evident that some degree of tolerance exhibited against high temperature stress which could be attributed to higher accumulation of carbohydrate, proline, adjustment of anatomical features, modification of antioxidant pool, better water status, lower fruit drop percent, in cv. Manipur as compared to cv. Assam under elevated carbondioxide and temperature condition. This indicates the differential responses of genotypes under future climate change conditions.ThesisItem Open Access Studies On Chemical Modification Of Wood For Improving Dimensional Stability And Other Mechanical Strength Properties By Treatments With Certain Thermoplastic / Thermosetting Resins And Acrylic Monomers(Assam Agricultural University; Jorhat, 2001) Deka, Manabendra; Baruah, K. K.ThesisItem Open Access Physico-Chemical Evaluation With Respect To Hydrocarbon And Energy Contents Of Certain Plant Materials That Grow Under Eco-Climatic Conditions Of North Eastern India(Assam Agricultural University; Jorhat, 2001) Kalita, Dipul; Saikia, C. N.ThesisItem Open Access PHYSIOLOGICAL PERFORMANCE OF SOME SALI RICE GENOTYPES UNDER DELAYED DATES OF SOWING(2015) Konwar, Priti BandanaA study was conducted during the sali seasons of 2012 and 2013 at the experimental field of Instructional cum Research (ICR) farm, and at the Department of Crop physiology, Assam Agricultural University, Jorhat to assess the physiological performance of seven selected sali rice genotypes namely, Satya (G1), Luit (G2), Monoharsali (G3), Jaya (G4), Bordhan (G5), Basundhara (G6) and Srimanta (G7) under delayed dates of sowing. All agricultural practices were followed as recommended while raising the crop in the field. The experiments in the field were laid out in split plot design with three replications where five sowing dates were allocated the main plots and seven genotypes were allocated sub-plots. Uptake kinetics studies were carried out in the laboratory using Hoagland solution. Results obtained during the investigation revealed that delayed dates of sowing had significant influence on various morpho-physiological, biochemical and yield attributes. As compared to timely sowing, delayed sowing resulted in progressive reduction in the values of parameters namely leaf area index, leaf area duration, in-vivo leaf nitrate reductase activity, total leaf chlorophyll content ,chlorophyll stability index, starch content in culm, leaf soluble protein, rate of photosynthesis, plant biomass, accumulated nitrogen in above ground biomass , longest root length, root volume, days to panicle emergence and yield attributing traits. However, net assimilation rate showed an increase upto 27th July sowing and there after it decreased upto 10th August sowing. Root to shoot ratio, chlorophyll a to b ratio, proline content and chaffy grain percentage showed an increasing trend with deferred dates of sowing. While comparison was made between timely sowing and the deferred dates of sowing lowest reduction in the values of grain yield were recorded in genotype Manoharsali and Srimanta (G3 and G7) (35.66 % and 35.03 % under D2 ) , (42.89% and 58.57% under D3), (58.07% and 65.32 % under D4 ) and ( 78.07% and 77.73 % under D5). These two genotypes recorded better performance in terms of parameters like leaf area index, leaf area duration, total leaf chlorophyll content, proline content in leaf, starch content in culm, leaf soluble protein, photosynthetic rate, nitrogen accumulation in biomass and plant biomass etc. Uptake kinetic studies revealed that the genotype Basundhara (G6) and Srimanta (G7) showed lowest Km values and the latter genotype also showed highest accumulation of nitrogen in plant biomass. Plant biomass at physiological maturity stage and grain yield at harvest showed significant positive correlation with leaf area index, leaf area duration, starch content at dough stage and leaf soluble protein. The genotype Srimanta (G7) showed higher grain yield in timely sowing situation and its percent reduction with delayed dates of sowing was lowest. Therefore the genotype Srimanta (G7) can be regarded as better genotype for delayed sowing. The genotypes Satya (G1), Monoharsali (G3) and Srimanta (G7) were found to be superior in terms of nitrogen uptake efficiency; however, their physiological nitrogen utilization efficiency were lower as compared to other genotypes.