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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 PHYSIOLOGICAL PERFORMANCE OF RAPESEED (Brassica rapa var. Toria) GENOTYPES UNDER RAINFED CONDITION OF ASSAM(2023) CHINTEY, RAJESH; Goswami, Ratna KinkorThe present research work entitled “Physiological performance of rapeseed (Brassica rapa, var. Toria) genotypes under rainfed condition of Assam” was carried out at the Instructional-cum-Research (ICR) Farm, Assam Agricultural University, Jorhat-13, Assam during rabi seasons of the years 2021-22 and 2022-23. The main objectives of the study were to find out the suitable superior genotypes based on the physiological efficiency and to identify the parameters which contribute significantly towards yield improvement in rapeseed. The field experiment was laid out in randomized block design with three replications comprising of 22 different genotypes of rapeseed including TS-38 (Check), TS-46, TS-67, TS-36, TS-29, TS-75-1, TS-75-1TL, TS-75-2ME, TS-75-2-MM, TS-76-1, TS-76-2, JT-90-1, Panchali, Bhawani, CG Toria-4, TKM-20-1, TKM-20-2, JT-14-5, PT-2018-09, CG Toria-3, Tapeshwari and PT-303. The crops were grown following the recommended package of practice. All the morpho-physiological, biochemical, quality parameters, yield attributes and yield of the crops were taken following the standard methodologies. The results of the study indicated a significant variation of all the morpho-physiological, phenological, quality parameters, yield attributes and yield among the genotypes. The genotypes, TS-75-2ME, TS-38, PT-303 and TS-36 exhibited morpho-physiological superiority with regard to more number of branches, stem diameter, accumulation of more photosynthates, more AGR, CGR and leaf chlorophyll. The same genotypes also recorded significantly higher yield attributes and seed yield. The correlation studies also showed a significant positive correlation of these parameters with seed yield in the set of the genotypes, indicating clearly that these parameters may be regarded as morpho-physiological indices for improving crop productivity in rapeseed. From the results, the genotypes, TS-75-2ME, TS-38, PT-303 and TS-36 may be regarded as superior genotypes suitable for growing under rainfed condition during rabi season in Assam and North-Eastern states of India and may be used as genetic sources in further yield improvement programme of rapeseed.ThesisItem Open Access PHYSIOLOGICAL PERFORMANCE OF CHICKPEA (Cicer arietinum L.) UNDER ORGANIC AND INTEGRATED NUTRIENT MANAGEMENT PRACTICES IN ASSAM CONDITIONS(2023) MANPHAI, NANG VISHAKA; Kalita, PrakashChickpea (Cicer arietinum L.), is one of the most important rabi season pulse crops of India that ranks second in area and third in production. In Assam the production and productivity of chickpea are 1,582 tones and 699 kg/ha respectively (Anon., 2017), corresponding an area of 2,429 ha (Anon., 2019). Every year Assam use to have a rice fallow land of 10.34 lakh ha (Deka et al., 2020) which can be utilized profitably to grow rabi pulses like chickpea, pea, lathyrus etc. using some adapted varieties for this region and nutrient management approaches . Chickpea being a leguminous crop can fix atmospheric nitrogen and thereby contribute to plant and soil health. The nodulation as well as nitrogen fixation capacity can be influenced by the form of nutrients applied (Shahzad et al., 2014). Substituting inorganic form of nitrogen partially as well as completely with organic sources has been reported to improve photosynthetic activity and dry matter production. Compared to the use of chemical fertilizers alone the integrated nutrient management (INM) practices are reported to result in significantly higher grain yield by improving nutrient uptake from the soil. A pot experiment entitled “Physiological performance of chickpea (Cicer aerietinum L.) under organic and integrated nutrient management practices in Assam conditions” was conducted in Rainout shelter phenotyping facility, Department of Crop Physiology, Assam Agricultural University, Jorhat-13 during the rabi season of 2022-23. The experiment was carried out in pots filled with dry soil by following two factor completely randomized design (CRD) with seven treatments and four genotypes of chickpea, which was replicated four times. The seven treatments studied were T1 (100% of recommended dose of N through Farm yard manure), T2 (100% of N through Vermicompost), T3 (100%of recommended dose of N through Enriched compost), T4 (50% of recommended dose of N through Farm yard manure + 50% of recommended dose of N through Urea), T5 (50% of recommended dose of N through Vermicompost + 50% of recommended dose of N through Urea), T6 (50% of recommended dose of N through Enriched compost + 50% N through Urea), T7 (100% of recommended dose of N through Urea). The dried soil was initially mixed thoroughly with well decomposed FYM in ratio of 3:1. Four chickpea genotypes namely IPC 07-28, IPC 11-112, IPC 06-77 and IPCK 02-29 were used for the study. Sowing was done on 16th November 2022 and subsequently the inter-cultural operations were carried out as and when required. Results revealed that all the morpho-physiological, biochemical, yield attributing traits and yield were significantly influenced by the genotypes and treatments. In terms of seed yield with urea as the sole source of nitrogen the genotype IPC 07-28 performed better (2.49 g plant-1) compared to other genotypes while IPCK 02-29 recorded the lowest performance (1.93 g plant-1). The genotype IPC 07-28 also recorded the highest seed yield (5.24 g plant-1 ) when vermicompost was used as the sole source of nitrogen as well as when N was supplied through the combination of vermicompost and urea each contributing 50% of the recommended dose of nitrogen . The highest value of accumulated nitrogen (0.57) was recorded in genotype IPC 07-28 when receiving 50% nitrogen from vermicompost and 50% from urea although their physiological nitrogen utilization efficiency was moderate. The genotype IPC 07-28 exhibited the highest per cent increase in the traits namely plant height (41.62%), whole plant biomass (79.06%), root volume (29.41%) root surface area (38.48%), RLWC (34.20%), number of nodules per plant (42.53%), nodule weight (27.90%), total chlorophyll content (91.67%), in-vivo leaf nitrate reductase activity (26%), membrane stability index (66.15%), plant nitrogen content (58.33%), photosynthetic rate (21.5%), physiological nitrogen utilization efficiency (48.55%), no. of pods plant-1 (59.77%), no. of seed pod-1 (13.17%), seed yield (44.52%), harvest index (47.88%) with treatment T5 (50% of recommended dose of N through Vermicompost + 50% of recommended dose of N through Urea) as compared to (T7) when nitrogen was supplied through urea only . The best performance of the genotype IPC 07-28 followed by IPC 06-77 after receiving 50% of recommended dose of N from vermicompost combined with 50% of recommended dose of N from urea may be causally related to the sustained availability of nitrogen, other nutrients as and growth promoters for the plants throughout the crop life cycle as well as decrease in the N loss as compared to the situation when nitrogen was completely supplied through urea.ThesisItem Open Access STUDY OF ROOT CHARACTERISTICS AND YIELDING ABILITY OF SOME MILLET UNDER LOW pH LEVEL(2023) CHAUDHARY, RAKESH KUMAR; Das, RanjanA pot experiment was carried out at the Stress Physiology Laboratory, AAU Jorhat, to evaluate the root characteristics and yield capabilities of millets under low pH conditions. Seven genotypes were chosen for research and cultivated in control conditions using a factorial completely randomised design with three replications. The genotypes were grown in two pH level 4.5 and 5.5. The investigation revealed that there was significant diversity within genotypes under low pH treatments in terms of morphophysiological features, tolerance efficiency, and yield attributing factors. Plant height, leaf area index, leaf area duration, root length, number of primary and secondary roots, and root volume were all significantly higher in the Gossaingaon genotype and significantly lower in the Bharathi genotype. Tolerant efficiency indices viz. CSI, MSI, and PHSI indices demonstrate that genotype Gossaingaon and China mujih also have higher values compared to non-tolerant one. Similarly yield and yield attributing characteristics such as panicle length, harvest index, tiller number, grain per panicle, and 1000 grain weight were recorded significantly greater in Gossaingaon and China mujih even at low pH levels. It can be recognized that some genotypes have a higher ability to grow in low soil pH conditions. Among the genotypes, Gossaigaon, China mujih, and CFMV 2 were found to be the least affected by low soil pH. The ability of tolerant genotypes to grow in low pH conditions may be related to a decrease in H202 and maintenance of chlorophyll content in the leaf as well as intact xylem and phloem size of the root. As a result, genotypes Gossaingaon and China mujih may be considered the most promising genotypes among the seven genotypes under lower pH values in the current study.ThesisItem Open Access EFFECT OF ACID MINE DRAINED WATER ON PHYSIOLOGY OF RICE (Oryza sativa L.) GENOTYPES(2023) Borgohain, Mriganka; Bharali, BhagawanTwo experiments laid out using Completely Randomized Design (CRD) were conducted in the Stress Laboratory, Dept of Crop physiology, Assam Agricultural University. The main objective behind the experiments was to study the effects of acid mine drained (AMD) water on physiology of some varieties of Ahu rice (Mashuri, Jaya, Chilaria, Lachit, Mulagabharu, Jyoti Prasad, Bishnuprasad, Kanaklata) and Sali rice (Ranjit sub-1, Moniram, Piyolee, Bahadur Sub-1, Kushal, Muglagabharu, Bina-2, Satyaranjan). The varieties were treated with the simulated AMD containing sulphur at pH<2 (HSO3-), pH 4-6 (S03-), pH>6.0 (SO42-) and pH 5 (Control) basally in soil at vegetative stage. Nitrogen as Urea @ 60Kg/ha (50% as basal and 50% at maximum tillering stages), and whole doses of Phosphorus (@40Kg/ha) and Potassium (@20Kg/ha) as SSP and MoP respectively were applied as basal before transplanting. In case of the Ahu Rice, the varieties treated with pH<2 (HSO3-) was highly affected in terms of overall reduction in specific leaf area (SLA) at maximum tillering stage(1.20 to 54.75%) at panicle initiation stage(1.02 to 56.73%), plant height (6.9 to 55.6%) at harvest , root biomass (2.9% to 49.8%) at harvest, total chlorophyll content (2.26% to 55.4%), nitrate reductase (NR) activity (0.08% to 45.3%), cell membrane stability (CMS) (1.10% to 60.78%) at maximum tillering and panicle initiation stages, and economic yield (1.30% to 80.3%). Similarly, in Sali rice, decrease in SLA at maximum tillering stage (0.0 to 23.91%) and at panicle initiation stage (0.0% to 26.92%), plant height at harvest (0.10% to 56.61%), total chlorophyll content (0.05% to 52%), CMS (0.0% to 31.67%), NR activity (0.24% to 31.67%), panicle length (1.31% to 41.89% ), panicle weight (3.60% to 51.64%) at maximum tillering and panicle initiation stages, test weight (4.30% to 62.02%), high density grains (0.07% to 43.19%), and economic yield (1.72% to 60.99%) except sterility percentage (0.0% to 114.85%) at harvest stage. Among the varieties, Mashuri (Ahu) and Ranjit Sub-1 (Sali) possessed higher CMS and lower lipid peroxidase activity accompanied by higher NR activity, chlorophyll contents and economic yield which are the key factors for tolerance mechanism.ThesisItem Open Access IDENTIFICATION OF MORPHO-PHYSIOLOGICAL MARKERS FOR COLD TOLERANCE IN BORO RICE (Oryza sativa L.) VARIETIES(2023) Devi, Hidangmayum Priyanka; Das, SangitaLow temperature is a significant abiotic factor that can severely impact rice cultivation, especially during the Boro season, where suboptimal temperatures can lead to reduced growth and yield. The present study was undertaken to identify morpho-physiological and biochemical markers associated with cold tolerance in Boro rice varieties. In the present study, 10 Boro rice varieties viz., Kanaklata, Sona Mahsuri, Disang, Lal Mahsuri, Jyoti Prasad, Dinanath, DRR 44K, Swarnabh, Cauvery, No.29 (BRRI dhan29) were used to identify the suitable varieties for growing under low temperature. The first experiment was conducted in the laboratory of the Department of Crop Physiology and Agriculture Biotechnology to identify Boro rice germplasm based on their germination studies. The germination tests were conducted under four different temperature regimes viz., 5-6°C (av.5.5°C), 7-9°C (av. 8°C), 10-12°C (av. 11°C) and ambient condition (28°C) using growth chambers and the experiment was laid in the factorial CRD with 3 replications. The study revealed that the varieties Kanaklata and Sona Mahsuri revealed superior performance in germination-related parameters than the other varieties. A field study was also conducted in the ICR farm, AAU, Jorhat during 2022-23 with an aim to identify the various morpho-physiological markers for cold tolerance in the abovementioned ten boro rice varieties. The experimental design was laid out in the RBD with three replications. Morphological parameters, viz. plant height, no. of leaves per plant, number of tillers per plant, shoot biomass, root dry weight and length of the longest roots were found to be highest in Kanaklata, followed by Sona Mahsuri, Disang, Swarnabh and Dinanath while the lowest was recorded in Lal Mahsuri. Physiological and biochemical parameter viz. proline content, total chlorophyll content and relative leaf water content were recorded highest in Kanaklata, followed by Sona Mahsuri, Disang, Swarnabh and Dinanath. Yield parameters viz. panicle length, panicle weight, no. of grains per panicle, grain yield per plant and harvest index were recorded the highest in Kanaklata followed by Sona Mahsuri, Disang, Dinanath and Swarnabh. Moreover, in correlation studies, the morphological trait such as the number of tillers per plant, shoot biomass and root biomass showed a positive correlation with yield and physiological, biochemical traits viz. relative leaf water content, proline content and total chlorophyll and yield related traits viz.; no. of effective tillers per plant Panicle weight and no. of grains per panicle also showed a positive correlation with grain yield. Therefore, these traits can be useful in breeding and crop management programmes for cold tolerance in Boro rice.ThesisItem Open Access Effects of Brassinosteroid on Morphophysiology and Yield of French Bean (Phaseolus vulgaris L.)(2023) Changmai, Bibha; Das, KaushikAn experiment entitled “Effects of Brassinosteroid on Morpho-physiology and Yield of French Bean (Phaseolus vulgaris L.)” was conducted during November, 2022 to February, 2023 in the Department of Crop Physiology and in the Experimental Farm, Department of Horticulture, Assam Agricultural University, to evaluate the effects of homobrassinolide on growth and yield of French bean. The experiment was carried out in two phases i.e. A) Laboratory experiment and B) Field experiment. The laboratory experiment was laid out in completely randomized design (CRD) with 4 replications using one variety (Falguni) of the crop. Seeds of French bean were treated with different concentrations of homobrassinolide viz. 0.25 ppm, 0.50 ppm, 0.75 ppm, 1.00 ppm and control (0 ppm) to examine the germination and seedling growth of the tested crop. Among all the applied concentrations of homobrassinolide, 0.50 ppm was found to show superior results in increasing the germination percentage, germination index, shoot and root lengths, shoot and root fresh weights, shoot and root dry weights and vigour index of the tested crop. The field experiment was conducted to investigate the effect of foliar application of homobrassinolide on morpho-physiology and yield development of French bean (variety Falguni). Foliar spray was done at 20 days after sowing (20 DAS) and 40 days after sowing (40 DAS). The experiment was laid out in Randomized block design (RBD) with four (04) replications and nine (09) treatments viz. T1 (0.25 ppm; single application : 20 DAS), T2 (0.50 ppm; single application: 20 DAS), T3 (0.75 ppm; single application: 20 DAS), T4 (1.00 ppm; single application: 20 DAS), T5 (0.25 ppm; double application: 20 DAS + 40 DAS), T6 (0.50 ppm; double application: 20 DAS + 40 DAS), T7 (0.75 ppm; double application: 20 DAS + 40 DAS), T8 (1.00 ppm, double application: 20 DAS + 40 DAS) and T9 (0 ppm; control). Among all the treatments, T2 (0.50 ppm; single application: 20 DAS) exhibited higher increase in plant height, leaf number, shoot and root fresh weights, shoot and root dry weights, chlorophyll content, leaf NPK content, root nodule number, nitrate reductase activity, yield and all yield attributing parameters. Single application of 0.50 ppm homobrassinolide resulted in the highest cost benefit ratio (1: 1.65), where 27.27% increase in yield over control was recorded.ThesisItem Open Access RESPONSE OF SOME BANANA GERMPLASM TO NATURAL COLD TEMPERATURE REGIME IN ASSAM(2021) Kalita, Jiliksweta; Kalita, PrakashBanana (Musa spp.) is one of the most important commercial fruit crops especially in the tropics and has high consumer demand worldwide. It contains good amount of health benefitting anti-oxidants, minerals and vitamins. Banana is a tropical fruit crop which belongs to the family ‘Musaceae’. It is a mesophytic plant and it’s cultivation is mostly confined between 30N and 30S of the equator with a mean temperature of 27C to 35C. Banana ranks first in production and third in area among fruit crops in India. India is the largest producer of banana in the world with a productivity of 35.8 metric tonnes/ha. Assam has a productivity of 13.9 t/ha (Hazarika et al., 2020). The lower productivity of banana in Assam may be attributed to certain abiotic stresses like moisture deficit, low temperature etc. The banana plant is susceptible to cold and frost if the temperature drops below 15C during the winter months of November and December (Simmon, 1959) and the situation in Assam also resemble this. When fruiting occurs in winter there will be slow development of bunches and the fruit may never fill well enough to become marketable because of the insufficient leaf surface and slow leaf activities (Lomas, 1970). The major effects of cold stress include growth reduction, leaf wilting, chlorosis, inhibition of photosynthetic performance, changes in membrane integrity and loss of cell compartmentation (Bo et al., 2017), impairment of enzymatic activity (Cheng and Song, 2006) and over-accumulation of reactive oxygen species (ROS) which ultimately may cause plant death (Suzuki et al., 2012). Keeping these facts in view, a study was conducted at the Experimental Farm, Department of Horticulture, Assam Agricultural University, Jorhat during the year 2020-2021. Twenty germplasm of banana viz., Sutijahaji(G1),Agnisagar(G2) Grand Naine (G3), Bogimanohar (G4),Amrit Sagar (G5),Digjowa (G6),Chenichampa(G7),Banria (G8),Barjahaji (G9), GobinTulsi (G10), Doodhsagar (G11), Balhakual (G12), Assamese Malbhog (G13), Simolu Manohar (G14), Jatikal (G15), Athiya (G16), Kachkal (G17), Bhimkal (G18), Honda (G19) and Savari (G20)were taken as test material to evaluate their response towards naturally occurring low temperature in Assam. Banana suckers of uniform size arising from the main crop during the month of February were used to grow the ratoon crop. Data on various morpho-physiological parameters were recorded in the months of August, December, January and February when the crop attained the age of 6th, 10th, 11th and 12th month. Low temperature progressively reduced the values of relative leaf water content, chlorophyll content (a,b, total), number of functional leaves, leaf area, stomatal conductance, transpiration rate, photosynthetic rate, quantum efficiency of PSII, days taken for leaf senescense etc. as compared to the August sampling while the lipid peroxidase activity ,intercellularCO2 concentration and days taken for leaf emergence was increased under low temperature. The germplasm Barjahaji (G9) showed higher values with respect to all parameters except lipid peroxidation, intercellularCO2 concentration and days taken for leaf emergence. As compared to August sampling, during winter months the reduction in values of various parameters was comparatively low in the germplasm Barjahaji (G9), Bhimkal (G18), Ahtiya(G16), Simolumanohar (G14) and Bogimanohar (G4). These germplasm were found to be superior in our study in terms of RLWC, Chlorophyll ‘a’, Chlorophyll ‘b’, total chlorophyll, number of functional leaves, leaf area, stomatal conductance, transpiration rate, photosynthetic rate, quantum efficiency of PSII, days taken for leaf senescense, number of hands per bunch, number of fingers per hand, weight of finger, and bunch weight. On the other handthese germplasm showed lower values of lipid peroxidation, intercellular CO2 concentration and days taken for leaf emergence during the winter months (December, January and February). During February, germplasm Barjahaji(G9),Bhimkal(G18),Athiya(G16)showed better recovery in RLWC by 2.62%, 5.11% and 2.63%, respectively, in photosynthetic rate by 7.71%, 7.56% and 2.84% , respectively and in quantum efficiency of PSII by 23.00%, 20.83% and 20.65%, respectively. The germplasm Bogimanohar (G4) also showed recovery in quantum efficiency of PSII by 19.60%. In the present study, the germplasm Barjahaji (G9) (17.68kg Bunch-1) was found to be thehighest yielder followed by Bhimkal (G18) (17.23kg Bunch-1) and Bogimanohar (G4) (17.18kg Bunch-1) whereas, the germplasm Chenichampa (G7) (11.27kgBunch-1) was found to be the lowest performer in this regard.Barjahaji ,Bhimkal and Bogimanohar registered 56.87%, 52.88% and 52.44% higher yield , respectively, over Chenichampa. From the correlation study, it was found that the banana yield was positively and significantly correlated with the parameters viz., number of fingers per hand (r= 0.4405), number of hands per bunch (r= 0.3536) weight of finger (r= 0.7348), number of functional leaves (r= 0.3685), and leaf area (r= 0.3299). From physiological point of view the germplasm Barjahaji(G9), Bhimkal (G18), Ahtiya(G16),Simolumanohar (G14) and Bogimanohar (G4) were found to be tolerant against low temperature as these germplasm have exhibited better values of physiological traits that are known to contribute positively towards growth and development and in majority of the cases towards yield.ThesisItem Open Access Nitrogen acquisition under elevated CO2 and temperature in rice (Oryza sativa L.)(AAU, Jorhat, 2021) Doulboruah, Pronamee; Das, RanjanA field experiment was conducted at stress physiology laboratory, AAU, Jorhat during kharif season of 2020-2021 to study the “Nitrogen acquisition under elevated CO2 and temperature in rice (Oryza sativa L.). The experiment was carried out in controlled environment under CO2 temperature gradient tunnel (CTGT), to understand the differential response of rice to higher level of CO2 i.e. CTGT-I at ambient CO2 395 ppm & temperature, CTGT-II at elevated CO2 (550±20ppm) + temp. of 4 0 C > ambient and CTGT-III at elevated CO2 (750±20ppm) + temp. of 6 0 C > ambient with four different level of N treatment viz. N0 (zero N), N1 (75% recommended dose), N2 (100% of recommended dose), N3 (125%of recommended dose). The experiment was laid out in two factorial completely randomized block design (FCRD) with 10 replications. The popular rice cultivar of Assam, Luit, was collected from research station of Agricultural University. This experiment was conducted on pot which was sown on 8th Aug 2020 and harvested between 28th Nov to 2nd Dec 2020. In the experiment under elevated CO2 and temperature there was a significance difference of crop growth parameters where highest value were recorded at CTGT-II with N3. In phenological data highest value was recorded at CTGT-III with N3. All biochemical and anatomical parameters also exhibit better result in CTGT-II with N3 as compared to CTGT-I. Membrane related phenomenon i.e. MSI was recorded as high at CTGT-II with N3. But there was a negative trend in H2O2 and lipid peroxidation where highest value was recorded at CTGT-III with N0. Similar result also found in water relation parameters and all physiological parameters. Chlorophyll florescence related phenomenon shows highest result in CTGT-II at N3. Likewise, yield attributing parameters gave highest value in CTGT-II with N3. Results shows that application of N significantly increased various morphological growth parameters as well as yield parameters in rice under elevated CO2 condition (at 550±20 ppm with 40 c temperature) under CTGT-II as compared to CTGT-I and CTGT-III. High temperature has a deleterious effect on plant growth and some related processes viz. physiological and biochemical activities because an effect on C: N ratio. Therefore, supplementation of N may play a pivotal role in amelioration of some deteriorative process like lipid peroxidation content and MDA content of leaves thereby reduced yield by affecting yield attributing parameters. Results indicated that higher doses of N under elevated CO2 and temperature invariably maintained not only the C:N ratio but also improved the physiological response positively. But at lower level of N in plant showed poor plant growth as well as metabolic de-arrangement because of low photo synthetic rate, nitrate reductase activity, chlorophyll loss and depression membrane stability index. Therefore, modification of agriculture and nutrient management technologies for future environments is important criteria for sustainable management of rice ecosystem.ThesisItem Open Access EFFECT OF SEED BIOPRIMING WITH INDIGENOUS FUNGAL ISOLATES ON GROWTH AND YIELD OF OKRA (Abelmoschus esculentus L.)(AAU, Jorhat, 2021) Bhuyan, Rijuleena; Das, KaushikA series of experiments were conducted during the year 2021 in the Department of Crop Physiology, AAU, Jorhat to evaluate the effect of seed biopriming by indigenous fungal isolates on germination, growth and yield of okra. Three different fungal strains viz., Trichoderma harzianum, Metarhizium anisopliae and Verticillium lecanii, isolated and prepared from indigenous sources were selected for the research programme. In the first experiment, which was conducted under laboratory condition, okra seeds were bioprimed with these fungal isolates with four different concentrations (0.30%, 0.50%, 0.70% and 0.90%) separately. Additional two separate sets, one with hydroprimed seeds and another with unprimed control, were also kept for comparison. Seed germination and early seedling growth of the tested crop in terms of germination percentage, germination index, root and shoot lengths, fresh and dry weights and vigour index of the seedlings were found to be increased by all the priming treatments. Among the different treatments, 0.50% T. harzianum, 0.70% M. anisopliae and 0.70% V. lecanii exhibited better promotive results compared to the other treatments. The second experiment, which was also a laboratory trial, was carried out to evaluate the combined effects of the different indigenous fungal biopriming agents. Among the different treatment combinations, T. harzianum (0.50%) + M. anisopliae (0.70%) showed the most promotive results in respect to germination and early seedling growth of okra. Third experiment was conducted in pots under shed-house to evaluate the combined effect of T. harzianum, M. anisopliae and V. lecanii as biopriming agents on morphophysiology, growth and yield of okra. For comparison other two sets were also kept, one with hydropriming treatment, and one as unprimed control. All the recorded growth and morphophysiological parameters such as plant height, leaf number, leaf area, root volume, shoot and root dry weights were increased by all the treatments. Plant water relation of the crop in terms of relative leaf water content (RLWC) was found to be positively affected by the applied seed priming treatments. Leaf chlorophyll content of the tested crop was also increased by the seed priming treatments. However, no such effect was observed on the leaf proline content of the crop. Yield and all the recorded yield attributing characters such as days to first flower initiation, fresh and dry weights of pod, fresh and dry weights of the seeds were positively affected by the applied treatments. All the fungal biopriming agents exhibited better results compared to the hydropriming treatment. Among the different bioprimning treatments, T. harzianum (0.50%) + M. anisopliae (0.70%) showed the most promotive results in respect to growth and yield enhancement in okra.
