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ThesisItem Open Access Effect of entomopathogenic fungi, Metarhizium anisopliae on growth and yield of french bean(AAU, Jorhat, 2017-07) Kurmi, Himanshu; Das, K.Experiments were carried out during September, 2016 to March, 2017 in the Department of Crop Physiology, Assam Agricultural University, Jorhat-13, to evaluate the effects of different concentrations of fungal isolate of Metarhizium anisopliae on french bean. In one experiment, fungal isolates of M. anisopliae at 105cfu/ml, 106cfu/ml, 107cfu/ml and 108cfu/ml concentrations were tested to determine their effects on germination and subsequent seedling growth of french bean under laboratory condition. It was observed that germination percentage, germination index, vigour index, shoot and root length, fresh and dry weight of shoot and root were affected by M. anisopliae isolates in a concentration dependent manner. Among the applied concentrations, 106cfu/ml and 107cfu/ml concentrations were found to be more stimulatory compared to control. Another experiment was conducted in field condition with these two concentrations (106cfu/ml and 107cfu/ml concentrations) to evaluate their effects on growth and yield of french bean. Three different modes of application, viz. seed treatment (before sowing), foliar application (15 DAS, 30 DAS and 45 DAS) and combination of seed treatment and foliar application were employed. Recorded data revealed that plant growth of french bean in terms of plant height, leaf number, leaf area, root volume, shoot and root dry weights were increased by M. anisopliae. Physiological parameters such as relative leaf water content, total chlorophyll content and leaf N P K content of french bean were also positively influenced by the fungal isolate. However, no significant alteration was recorded in leaf proline content irrespective to mode of application and concentration of fungal isolate. Among the different treatments, 107cfu/ml concentration was found to be more stimulatory when applied as combination of seed treatment and foliar spray. At this treatment combination, pronounced stimulatory effects were recorded on yield and different yield attributing parameters of french bean. From the results of this investigation, it can be concluded that in addition to its well established protective role against insect pest, M. anisopliae also exhibits stimulatory effects on growth, development and yield of the crop.ThesisItem Open Access EVALUATION OF PHYSIOLOGICAL PERFORMANCE OF LENTIL GENOTYPES IN ORGANIC SITUATION UNDER DEFERRED DATES OF SOWING IN RICE FALLOW LAND(AAU, Jorhat, 2017-01) Sarmah, Bhargob; Kalita, PrakashAn investigation was carried out during November, 2016 to March, 2017 in the Instructional-cum-Research (ICR) farm and Department of Crop Physiology, Assam Agricultural University, Jorhat-13, to evaluate the physiological performance of lentil genotypes in organic situation under deferred dates of sowing in rice fallow land. Five lentil genotypes namely HUL-57, SLC-102, PL-406, KLS-218 and SLC- 101were used for the study. There were three dates of sowing viz. 15th November, 30th November and 15th December. The land used for raising the crop has been maintained for last ten years as organic plot and has been used for raising winter rice crop. The lentil crops raised were supplied with nutrients through organic inputs (well rotten cow dung and enriched compost) and the chemicals used for plant protection were also organic. Significant variations were recorded among the genotypes in terms of various parameters namely total leaf chlorophyll content, relative leaf water content, in- vivo leaf nitrate reductase activity, root: shoot ratio, dry matter partitioning, number of pod per plant, number of seeds per pod, grain yield and harvest index .These parameters exhibited a decreasing trend with delay in the date of sowing from the recommended one. However lipid peroxidase activity was found to increase due to delay in sowing of lentil genotypes. Among the genotypes the HUL-57 performed the best compared to the other genotypes under both the situations when sowing was done at recommended date of sowing and when the sowing was delayed. On the other hand the genotype SLC-101 registered the lowest performance. The genotype HUL-57 exhibited the lowest percent reduction in terms of total leaf chlorophyll content, relative leaf water content, in- vivo leaf nitrate reductase activity, root: shoot ratio, dry matter partitioning, number of pod per plant, number of seeds per pod, grain yield etc. followed by the genotype KLS-218. When the sowing was delayed by 15 days (30th November) on an average biomass and grain yield were decreased by 12.29% and 3.30% respectively, whereas the corresponding decreases were 35.49% and 13.53% when biomass and grain yield from 15th December sowing were compared with that of 15th November sowing. In case of HUL-57 the decrease in biomass and grain yield were only 33.97% and 12.11% respectively when performance under 15th December sowing were compared with that of 15th November sowing. The better performance of HUL-57 could be attributed to better performance of this genotype in terms of the parameters namely total chlorophyll content, relative leaf water content, in- vivo leaf nitrate reductase activity, root: shoot ratio, dry matter partitioning, number of pod per plant, number of seeds per pod etc. As with the delay in sowing resulted in the exposure of the lentil plants to moisture shortage coinciding with the vegetative and early reproductive stages, the genotype HUL-57 can be labeled as moisture shortage tolerant genotype; more over this genotype can be said to have adjusted efficiently under the decreasing length of photo period as encountered when sowing was delayed.ThesisItem Open Access PHYSIOLOGICAL BASIS OF SUBMERGENCE TOLERANCE IN LOWLAND RICE(AAU, Jorhat, 2017-07) Talukdar, Krishna; Das, RanjanThe experiment was conducted for two years during Kharif season 2016 and 2017. About 200 genotypes from different adaptations were collected and screened for submergence tolerance by SES scoring developed IRRI, Philippines. After screening, five genotypes viz. Tejai longpi, Marjina, Badam bao, Sok langlu and OM5451 were selected based on survival, recovery characteristics and comparing with submergence susceptible line IR-64. Significant variation was observed amongst the genotypes for all the parameters viz. lipid peroxidation, leaf soluble protein content, leaf temperature and Membrane Stability Index, Chlorophyll Stability Index, Nitrate Reductase Activity. However, a significant increase in MDA content, root volume, root: shoot ratio was observed under stress condition. Stress induced reduction in stem elongation and plant height was found highest in Badam bao which could be correlated to an increase in total carbohydrate content in the genotype. Badam bao also recorded the lowest reduction in total chlorophyll content and tiller number under submerged condition. It can be assumed that Badam bao being a tall variety has got an inherent capability to cope submergence stress by reducing stem elongation and increasing tiller number thereby increasing yield. In the present study, under submerged condition, Badam bao could maintain its yield and yield attributes in terms of 1000 grain weight and no. of grain /panicle. This could be correlated with a significant increase in flag leaf area in the genotype. Modern high-yielding rice varieties are highly susceptible to flooding whereas traditional cultivars have acquired moderate tolerance to flooding but they carry the penalty being of inherently lower grain yields. Therefore, in the present investigation, it was found that two traditional genotypes viz. Badam bao and Marjina could be grown successfully under submerged condition with moderately higher yield.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.
