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Kerala Agricultural University, Thrissur
The history of agricultural education in Kerala can be traced back to the year 1896 when a scheme was evolved in the erstwhile Travancore State to train a few young men in scientific agriculture at the Demonstration Farm, Karamana, Thiruvananthapuram, presently, the Cropping Systems Research Centre under Kerala Agricultural University. Agriculture was introduced as an optional subject in the middle school classes in the State in 1922 when an Agricultural Middle School was started at Aluva, Ernakulam District. The popularity and usefulness of this school led to the starting of similar institutions at Kottarakkara and Konni in 1928 and 1931 respectively.
Agriculture was later introduced as an optional subject for Intermediate Course in 1953. In 1955, the erstwhile Government of Travancore-Cochin started the Agricultural College and Research Institute at Vellayani, Thiruvananthapuram and the College of Veterinary and Animal Sciences at Mannuthy, Thrissur for imparting higher education in agricultural and veterinary sciences, respectively. These institutions were brought under the direct administrative control of the Department of Agriculture and the Department of Animal Husbandry, respectively. With the formation of Kerala State in 1956, these two colleges were affiliated to the University of Kerala. The post-graduate programmes leading to M.Sc. (Ag), M.V.Sc. and Ph.D. degrees were started in 1961, 1962 and 1965 respectively.
On the recommendation of the Second National Education Commission (1964-66) headed by Dr. D.S. Kothari, the then Chairman of the University Grants Commission, one Agricultural University in each State was established. The State Agricultural Universities (SAUs) were established in India as an integral part of the National Agricultural Research System to give the much needed impetus to Agriculture Education and Research in the Country. As a result the Kerala Agricultural University (KAU) was established on 24th February 1971 by virtue of the Act 33 of 1971 and started functioning on 1st February 1972. The Kerala Agricultural University is the 15th in the series of the SAUs.
In accordance with the provisions of KAU Act of 1971, the Agricultural College and Research Institute at Vellayani, and the College of Veterinary and Animal Sciences, Mannuthy, were brought under the Kerala Agricultural University. In addition, twenty one agricultural and animal husbandry research stations were also transferred to the KAU for taking up research and extension programmes on various crops, animals, birds, etc.
During 2011, Kerala Agricultural University was trifurcated into Kerala Veterinary and Animal Sciences University (KVASU), Kerala University of Fisheries and Ocean Studies (KUFOS) and Kerala Agricultural University (KAU).
Now the University has seven colleges (four Agriculture, one Agricultural Engineering, one Forestry, one Co-operation Banking & Management), six RARSs, seven KVKs, 15 Research Stations and 16 Research and Extension Units under the faculties of Agriculture, Agricultural Engineering and Forestry. In addition, one Academy on Climate Change Adaptation and one Institute of Agricultural Technology offering M.Sc. (Integrated) Climate Change Adaptation and Diploma in Agricultural Sciences respectively are also functioning in Kerala Agricultural University.
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ThesisItem Open Access Mitigation of solar ultraviolet-B radiation induced photoinhibition in photochemistry and photosynthesis of rice (Oryza sativa L.)(Department of Plant Physiology, College of Horticulture, Vellanikkara, 2016) Shafeeqa, T.; KAU; Nandini, KSun light contains ultraviolet (UV) radiation which is separated in to UV-C (100-280nm),UV-B (280-320 nm) and UV-A (320-400nm). Evidences from data collected from both satellite and field experiments indicated an increase in UV-B radiation reaching on the earth surface, due to decrease in ozone layer. Hence, UV-B has become more challenging nowadays causing threat to agriculture production in tropics. UV-B exclusion and enhancement studies conducted in the Department of Plant Physiology, College of Horticulture, Vellanikkara have revealed a decline in rice yield due to UV-B radiation in rice varieties Jyothi and Uma (Wagh, 2015). The present study entitled “Mitigation of solar ultraviolet-B radiation induced photoinhibition in photochemistry and photosynthesis of rice (Oryza sativa L.)” was conducted during 2014-2016 in the Department of Plant Physiology, College of Horticulture, Vellanikkara with the objective to understand the photo protective potential of ecofriendly stress mitigating chemicals on photoinhibition and photosynthesis of rice (Oryza sativa L.) under solar ultraviolet- B radiation. The pot culture experiment was conducted during November 2015 to March 2016 with rice variety Uma under two growing conditions viz. open condition- where the crop exposed to 100% solar radiation and polyhouse condition- which transmit 20% reduced full spectrum solar radiation including UV-B. Three ameliorative chemical treatments with two concentrations such as glycine betaine (10ppm and 20ppm), ascorbic acid (50ppm and 100 ppm) and combination fungicide 25WG trifloxystrobin + 50 WG tebuconazole (Nativo 75 WG- 50ppm and 70ppm) were given as foliar application at 30th and 60th DAT and observations were taken 15 days after each chemical spraying. The experiment was laid out as completely randomized design (CRD). The UV-B and Photosyntheticaly Active Radiation (PAR) in both conditions were monitored regularly throughout the crop period. The data on UV-B and PAR revealed significantly higher UV-B (2.18 Wm-2) and PAR (1786 μmolm-2s-1) during March-2016 under ambient condition. All growth phenophases were delayed under 100% solar radiation. Combination fungicide 25 WG trifloxystrobin+50WG tebuconazole 70ppm enhanced grain filling period under both the growing condition compared to other chemical treatments; the ultimate realization being a relatively good yield. Gas exchange parameters like photosynthetic rate, stomatal conductance and transpiration rate decreased during reproductive phase under 100% solar radiation, where the crop experienced high UV-B radiation. Among chemicals, 25 WG trifloxystrobin+50WG tebuconazole 70ppm enhanced the above parameters by alleviating the photoinhibition in photosynthesis and PSII activities. Photochemical efficiency as indicated by high Fv/Fm ratios was enhanced by foliar application of 25 WG trifloxystrobin+50WG tebuconazole 70ppm. High chlorophyll content, catalase activity and xanthophyll content were observed under reduced UV-B condition. Among chemical treatments significantly higher chlorophyll content was recorded for the rice plants treated with 25 WG trifloxystrobin+50WG tebuconazole 70ppm and this might be the reason for the increased photosynthetic rate in plants due to its application. The maximum yield contributed by 25 WG trifloxystrobin+50WG tebuconazole 70ppm may be due to the enhancement in thousand grain weight and number of spikelet per panicle, more photosynthetic rate and less fluorescence emission / increased photochemical efficiency of PS II, more chlorophyll content, catalase activity and reduction in the synthesis of secondary metabolites like flavanoid and xanthophylls. The ameliorative effect of this chemical has to be explored under field level for better results and recommendation to farmers for raising 3rd crop during puncha season.ThesisItem Open Access Spectral management for improving hotosynthetic efficiency in polyhouse cultivation of vegetables(Department of Plant Physiology, College of Agriculture, Vellayani, 2016) Anjana, J Madhu; KAU; Roy StephenPlant growth is influenced by both the quality and intensity of light. The transmittance of light by different shade nets are unique. Hence the spectral quality of light vary under each coloured net. Different wave length of light influence specific physiological process. In this context, the study entitled “Spectral management for improving photosynthetic efficiency in polyhouse cultivation of vegetables” was conducted at the Dept of Plant Physiology, College of Agriculture, Vellayani and at Pothencode, Thiruvananthapuram during 2014- 2016. The main objective was to study the morphological and physiological responses of vegetables, viz. tomato, salad cucumber, capsicum and yard long bean exposed to spectral modification through different colored shade nets. A survey was conducted in 20 polyhouse units in Thiruvananthapuram district to know the adoption of shade nets by the farmers practicing polyhouse cultivation. The experiment was done in a polyhouse of dimension 500m2, which was divided into five parts on an east-west direction roofed with two photoselective and two neutral shade nets of four different optical properties and one part without any shade net. The light interception by shade nets were analysed using spectro radiometer at University of Agricultural Science, Bangalore. The green net reduced 59.9%, white net reduced 55.14% and red net reduced 41.05% of red light compared to open. Four different crops, viz. salad cucumber, yardlong bean, capsicum and tomato were grown under these shade nets. Weather parameters such as Photosynthetically Active Radiation (PAR), global radiation and temperature were recorded but didnot show much variation. The pollen viability was not altered by spectral variation. Earliness to flowering, fruiting and fruit maturity was observed in open condition for salad cucumber and capsicum. The number of leaves at first flowering was higher in white net for salad cucumber and yardlong bean while it was higher in red net for capsicum and tomato. Specific Leaf Area was significantly higher under red net for salad cucumber (979.52cm2g-1), capsicum (564.21cm2g-1) and tomato (631.18 cm2g-1). The same trend was followed in case of photosynthetic rate also. The internode elongation was found to be minimum in open condition for all the four crops. The leaf anatomy of salad cucumber grown under white net showed higher vascular thickness. Setting percentage was higher in white and green shade nets for salad cucumber (85.40%) and yardlong bean (89.35%) respectively where as red net was suitable for capsicum (80.99%) and tomato (81.80%). Higher shoot weight and root weight were observed under white shade net for tomato. Root shoot ratio and total dry matter content was higher in capsicum grown under red shade net. Transpiration rate of yardlong bean and tomato plants grown under green shade net was higher while higher transpiration rate of salad cucumber and capsicum was observed under white shade net. The pigment composition of salad cucumber was higher under black shade net. Abaxial stomatal frequency in all the four crops was higher in open condition. Total soluble protein content of tomato and salad cucumber at flowering stage was higher under red shade net. Higher carbohydrate content was observed under open condition in case of yardlong bean, capsicum and tomato. Phenol content increased in tomato plant grown under white shade net. There was no significant variation in IAA. Higher crude protein was observed in yardlong bean grown under white shade net while the crude fibre was higher under open condition. Ascorbic acid was higher in capsicum grown under open condition while for tomato it was under white shade net. Spectral modifications through shade nets altered morphological and physiological responses of salad cucumber, yardlong bean, capsicum and tomato. Varietal suitability was observed in different shade nets. Photosynthetic efficiency was also influenced by shade nets and reflected in the yield of selected crops. Red net was suitable for capsicum and tomato while white net was ideal for salald cucumber and green for yardlong bean.ThesisItem Open Access Carbon dioxide enrichment mediated plant-microbe interaction in cowpea (Vignaunguiculata L.) under water stress(Department of Plant Physiology, College of Agriculture, Vellayani, 2016) Athibha, P B; KAU; Manju, R VThe level of CO2 in the atmosphere is rising at an unprecedented rate. According to NOAA (National Oceanographic and Atmospheric Administration) 2014, global concentration of CO2 has reached 400 ppm for the first time in recorded history. This rise, along with other trace gases in the atmosphere is widely thought to be a primary factor driving global climate change. Moreover the report of IPCC, 2012 has reconfirmed the increasingly strong evidence of global climate change and projected that the globally averaged temperature of the air would rise by 1.8–6.4°C by the end of the century. Pulses are the main sources of protein and is commonly called poor man’s meat. They are also used as fodder and concentrate for cattle. Pulses are responsible for improving soil fertility by increasing the amount of N2 in the soil. Drought is a recurring problem limiting pulse production in rainfed areas. High frequency of crop failure and yield instability due to biotic and abiotic stresses also contribute to low productivity in pulses. The pulse production scenario is also getting affected by the changing climate and the resulting rise in temperature and decline in rainfall. Under such changing climatic scenario, soil microbes play an important role in the maintenance of physicochemical properties of soil and also in making the soil nutrients available to the plants. In this context, the current programme “Carbondioxide enrichment mediated plant- microbe interaction in cowpea (Vigna unguiculata L.) under water stress ” attempts to study the water stress tolerance character and N2 fixation efficiency of cow pea as influenced by microbial inoculants under elevated CO2 condition. This investigation will help to design improved production technologies with suitable varieties for a changing climatic scenario. Two pot culture experiments were conducted at different carbon dioxide concentrations with three different levels of soil moisture regimes i.e Field capacity, 75% field capacity and 50% field capacity. The cowpea seeds were sown in pots inside OTCs and in open field, one set with microbial seed inoculation and the second set without inoculation. The technology used for subjecting the plants to elevated CO2 environments is the Open Top Chambers (OTC) system. In both set of experiment entire crop period was completed in OTCs. Respective moisture stress levels were imposed during the second month. Experimental plants were maintained for a period of three months. Observations on growth parameters and microbial population studies were done at the end of CO2 exposure period and all the other parameters were taken at monthly intervals. The experiments were laid out in CRD with 18 treatments and three replications. The observations on growth parameters during first month of CO2 exposure on cowpea inoculated with Rhizobium revealed a reduction in specific leaf area by 21.39% under elevated CO2 condition compared to absolute control. Among the physiological and biochemical parameters studied, highest relative water content was recorded under elevated CO2 (4.69%). Carbon dioxide enrichment significantly lowered the stomatal frequency by 28.40 % and transpiration rates by 89.27%. Significant increase in total chlorophyll contents by 50 % was registered under elevated CO2 conditions. Per cent leakage was found significantly lower (38.74%) under CO2 enriched treatment compared to control. Among physiological parameters, a marked rise in phenol content was noticed by 56.68% under elevated CO2. Significant increase in reducing sugars, free amino acid, and ascorbic acid contents by 5.97%, 23.92% and 63.79% was recorded in elevated CO2. Protein content was found decreasing under elevated CO2 by 29.02%. The observations on growth parameters during water stress period in cowpea inoculated with Rhizobium revealed a reduction in specific leaf area by 17.24% under elevated CO2 condition compared to absolute control. Root and shoot dry weights were also found to be higher by 56.08% and 140.77% under elevated CO2 resulting an increase in root shoot ratio by 36.51%. Dry matter production was recorded 116% higher under elevated CO2. Parameters related to nitrogen fixation was recorded lower leaf nitrogen status (17.15% reduction), nitrogen use efficiency (36.46% reduction), and soil nitrogen status (8.79% reduction) under elevated CO2. But the Rhizobial inoculated plants was found to have a positive influence on soil nitrogen status (8.46% increase). Under elevated CO2 tremendous increase in root nodule number plant and nodule dry weight, but Rhizobium doesn't have any significant influence on this parameter. Among the physiological and biochemical parameters studied, highest relative water content was recorded under elevated CO2 (18.57%). Carbon dioxide enrichment significantly lowered the stomatal frequency by 15.53% and transpiration rates by 88.12%. Significant increase in total chlorophyll contents by 13.26 % was registered under elevated CO2 conditions. Per cent leakage was found significantly lower (51.45%) under CO2 enriched treatment compared to control. Among biochemical parameters, significant increase in reducing sugars, free amino acid, phenol, SOD and ascorbic acid contents by 22.63%, 30.65%, 67.56%, 42.12% and 34.06% was recorded in elevated CO2. Protein content was found decreasing under elevated CO2 by 44.92%. Nitrogen fixation efficiency was found to be decreased in terms of reduced leaf nitrogen status under elevated CO2. But nodule number per plant and nodule dry weight were increased. Rhizobial inoculated cowpea plants were observed to have better growth and improved stress tolerance in terms of better leaf water status and membrane integrity under elevated CO2. In the case of cowpea inoculated with P.indica during first month of CO2 exposure, number of leaves (33.30%)was found to be highest under elevated CO2. Lower stomatal frequency (35.78%), transpiration rate (86.89%) and per cent leakage (63.25%) were observed prominently under elevated CO2 compared to open control. Significant increment in reducing sugars by 21.78%, phenol by 77.71%, free amino acid content by 27.42% was recorded under elevated CO2. SOD and ascorbic acid content was found increased by 49.39 % and 8.05 % under elevated CO2 treatment compared with control. Root weight, shoot weight and total dry matter production were found enhanced by 42.39%, 27.27% and 35.31% under elevated CO2 in comparison with control. In the case of water stress also, elevated CO2 was found to have positive influence on growth like number of leaves (57.27%). Significant increment of relative water content (13.933%), total chlorophyll (124.9%), reducing sugar (23.43%), phenol(135.5%) was recorded under elevated CO2 in comparison with control. P. indica inoculated plants under CO2 was found to have better stress tolerance. This was achieved through maintenance membrane integrity and stomatal modifications. There was reduction in stomatal characters like stomatal frequency and stomatal conductance resulting in reduced transpiration and better tissue water status. There were enhanced accumulation and increased activity of antioxidants like ascorbic acid and SOD. This also would have helped the experimental plants in achieving better stress tolerance. The present investigation was carried out with the objective to study the water stress tolerance character and N2 fixation efficiency of cowpea as influenced by microbial inoculants under elevated CO2 condition. Considering all the physiological, biochemical studies conducted, it can be concluded that carbon dioxide enrichment has a positive role on water stress tolerance character of cowpea variety Bhagyalakshmy. There was further enhancement of stress tolerance by both microbial inoculants, Rhizobium sp and P.indica. The underlying tolerance mechanisms were found to be stomatal modifications resulting in reduced transpiration and better tissue water status, activation of antioxidants like ascorbic acid and better maintenance of membrane integrity. Nitrogen fixation efficiency was improved tremendously by elevated CO2 in terms of nodule number per plant and nodule dry weight but leaf nitrogen content and nitrogen use efficiency were reduced by CO2 enrichment. The outcome of the programme reveals the possibility of improving yield potential and stress tolerance under elevated CO2 by integrating photosynthesis and nitrogen use efficiencies with the application of microbial inoculants like P.indica. ReferencesThesisItem Open Access Photosynthetic efficiency and productivity of gynoecious parthenocarpic cucumber in naturally ventilated poly house(Department of plant physiology, College of horticulture, Vellanikkara, 2015) Gayathri, Rajasekharan; KAU; Nandini, KPoly house cultivation of vegetables is an emerging approach for production of vegetables in Kerala. The main principle of poly house cultivation is the facilitation of favourable micro-climates, which favour maximum production. The top of poly house is cladded with UV-stabilised plastic sheet which selectively screen the various spectral components of solar radiation and transform direct sunlight into scattered light inside. This type of spectral manipulation is aimed to specifically promote desired physiological processes and to modulate morphological and photosynthetic responses of plants. Hence, basic information on the physiological aspects involved in the photoresponse of crop in poly house is needed to realize maximum yield potential. In this context, a study was undertaken in a farmer’s field at Thannyam to compare the photosynthetic productivity of gynoecious parthenocarpic cucumber in poly house and open condition. High light intensity, Ultra violet (UV) radiation and Photosynthetically Active Radiation (PAR) caused a stressful environment which in turn reduced most of its morphological and biochemical characters in cucumber grown under open condition. However ambient CO2 concentration, which decides the photosynthetic rate was more under polyhouse condition. Poly house cladded with UV stabilized sheet, reduced light intensity, UV-radiation and PAR favoured most of the morphological characters of the crop. The morphological characters like leaf area, Leaf Area Index (LAI), number of leaves, number of nodes and internodal length were significantly high for poly house grown cucumber. The chlorophyll content- Chl a, b and total chlorophyll in leaves was significantly high when grown under poly house. However, the activity of IAA Oxidase (IAAO) observed at 15 and 60 DAS was significantly lower inside the poly house indicating auxin availability for morpho-physiological fuctions. The Gibberelic acid content also increased but significant difference was observed only at 75 DAS in poly house grown crop. Photosynthetic rate of the crop under both conditions when recorded gradually increased from 15 DAS to 45 DAS and thereafter declined. This was significantly high under open condition at 15, 30 and 45 DAS, whereas it was significantly high in poly house only at 60 and 75 DAS. The poly house crop could maintain higher photosynthetic rate even at later growth stages of crop thereby prolonging the crop duration. Transpiration rate was significantly high under open condition at 30 DAS, but significantly higher values were observed in poly house condition at 45 and 75 DAS. The lower photosynthetic rate was due to low influx of CO2 in to mesophyll cells which is evident from low intercellular CO2 concentration in the poly house crop. This is also related to high stomatal resistance inside the poly house at 15 and 30 DAS. The carboxylation efficiency, which relates to photosynthetic rate, was significantly high at 60 and 75 DAS in the poly house crop. The photochemical efficiency of PS II as indicated by Fv/Fm ratio was higher under poly house environment. Canopy temperature depression did not give any significant difference between two conditions. Light absorption coefficient was significantly high in open condition where the LAI was less. The lower values of light absorption coefficient observed inside the poly house may be related to high LAI. There was no significant difference in number of days to flowering and days to first harvest between open and poly house grown crops. But the number of days to last harvest and number of harvests made from poly house grown crop were significantly high when compared to open condition. The yield contributing components such as number of fruits per plant, fruit weight, yield per plant and marketable yield were significantly high for poly house grown crop. Early senescence of the crop was observed under open condition compared to poly house. Retention of more chlorophyll content even at later stages of crop delayed senescence in poly house grown crop. The ascorbic acid content, one of the quality parameter was significantly high in crop grown under open condition. Organoleptic evaluation of fruits revealed that the poly house grown crops maintained significantly high colour, texture and overall acceptability of the fruits. This study suggests that the diffused light and equal distribution of radiation over the crop canopy favoured morphological characters of poly house grown crop. This in turn helped the crop to maintain high photosynthetic rate and carboxylation efficiency even at later stages of the crop which resulted in increased number of harvest in poly house.ThesisItem Open Access Growth and physiology of isachne miliacea roth. in different soil types and its sensitivity to common herbicides(Department of plant physiology, College of horticulture, Vellanikkara, 2015) Suada, A P; KAU; Girija, TIsachne miliacea Roth. is one of the predominant weed in the low land rice fields of Kerala. The weed belongs to the family poaceae. Locally it is known as ‘Chovverippullu, Naringa, Njammal, Changalipullu.’ Previous studies conducted in Kerala Agricultural University showed that I. miliacea alone can contribute to 61 per cent reduction in the production of rice in Onattukara region. Presently, the weed is reported to be spreading to other rice growing regions of Kerala. It is found both during the Rabi and Kharif seasons. Eradication of the weed is very difficult, as it is propagated through seeds and stem cuttings. Hence a study was proposed to understand the growth and propagation of I. mliacea in different rice growing soils and also to understand the response of the weed to common herbicides popular in the state. The effect of different soil types on growth and phenology of I. miliacea was studied in pot culture with soil collected from five different rice growing regions viz. Onattukara, Kole, Kuttanad, Pokkali and Palakkad. Ten kg soil each was filled in plastic boxes of size 50 x 25 cm and five replications was maintained for each soil type. Ten seeds were sown in each box and the germination was noted. At two leaf stage when the seedlings were identifiable, a single seedling was retained in each box and the excess seedlings were removed, irrigated regularly and the different phenophases and the morphological attributes were observed at 15 days interval. The study showed that soil type had a profound influence on the phenology and growth pattern of the weed. Due to high acidity (pH -3.6) and salinity (EC – 4.46 dS/m) seeds sown in Pokkali soils did not germinate. Plants grown in Kuttanad soil showed earlier germination, tillering, flowering, seed formation and seed maturation, while those from Palakkad soil required more number of days to reach these phenophases. The variation in morphological attributes such as total shoot length, leaf number, internodal length, number of panicles and seeds produced per plant were significant. Plants grown in Palakkad soil had higher total shoot length and internodal length as compared to Kuttanad soil, but the leaf number, number of panicles per plant and number of seeds produced per panicle were higher in Kuttanad soil, where the potassium, phosphorus and organic content was higher compared to other soils. As the nutrient status of Onattukara and Kole land soils were similar (potassium, phosphorus, magnesium, zinc, manganese and sulphur), the performance of the weed in those two soil types were also on par for many of the morphological characters. Propagation of I. miliacea was affected by ambient temperature, shade, depth of burial and moisture level of soil. The seeds germinated when the temperature range was between 15 - 400C, the highest germination was obtained at 250C. Growth of the weed was highest in open condition compared to shaded condition. Under 50 per cent shade, seed germination declined by 70 per cent. Higher germination per cent of weed was obtained under moist condition, while stem cuttings performed well in both moist and submerged condition. The germination per cent of the weed, reduced with depth of burial. Sensitivity of the weed to pre emergence herbicides was tested using seed bioassay technique. In the first set, herbicide soaked filter paper was placed at the bottom of petri plates and seeds were placed on it (TP method). In the second set, the herbicide soaked filter paper was placed on top of the seeds and another water soaked filter paper was placed at the bottom (BP method I). In the third set, seeds were placed in between two filter paper soaked with herbicides (BP method II). BP method II gave the best result for all the pre emergence herbicides. However, oxyfluorfen and butachlor showed higher weed suppression in all the methods tried. Sensitivity of the weed to post emergence herbicides was tested using whole plant bioassay technique. Here, the weed was grown in mud pots and the herbicides were sprayed when the weed was in the vegetative phase. Among post emergence herbicides tested, best control was obtained for azimsulfuron followed by cyhalofop butyl and fenoxaprop p- ethyl. The weed was susceptible to these chemicals. In the case of bispyribac sodium and penoxsulam though initial control was observed, regrowth was seen after two weeks and so the chemical was classified as moderately resistant to the weed. The weed was resistant to pyrazosulfuron, where no drying symptoms were observed. All the four non-traditional rice herbicides tested viz., glyphosate, diuron, paraquat and glufosinate ammonium gave excellent control of I. miliacea and no regrowth was observed after two weeksThesisItem Open Access Morpho-physiological changes in rice due to application of selected post emergent herbicides(Department of Plant Physiology, College of Horticulture, Vellanikara, 2014) Ramanarayana, C V; KAU; Girija, TThe study on “Morpho-physiological changes in rice due to application of selected post emergent herbicides” was conducted during 2013-2014 at Alappad kole lands in farmer’s field. The objective of the experiment was to study the morphological, physiological and biochemical changes in rice due to application of Acetyl CoA carboxylase and Acetolactate synthase enzyme inhibitors and their effect on growth and yield of rice. The experiment was laid out in RBD with four replications and there were seven treatments comprising of three Acetyl CoA carboxylase enzyme inhibitors viz., Cyhalofop butyl, Fenoxaprop -p- ethyl and Metamifop and three Acetolactate synthase enzyme inhibitors viz., Bispyribac sodium, Azimsulfuron and Almix with Hand weeded as control. Herbicides were sprayed on 15 DAS. Observations on morphological, physiological, biochemical, yield attributes and yield of rice were recorded. Biochemical estimations were done on 7 days after herbicide application and at the time of flowering. Morphological characters were studied at 15 days interval. Herbicide application resulted in a two to four percent reduction in height and one to six percent reduction in tiller number of rice plant at harvest as compared to plants in the Hand weeded plot. Effect of herbicides on growth attributes viz., RGR, CGR and NAR indicated that at the initial and final stages of growth there was no significant difference between the treatments. However during the critical stages of growth i.e., 45-75 DAS significant variation was seen. Among the herbicide treatments, Bispyribac sodium.followed by Cyhalofob butyl applied plots had higher values as compared to the other herbicides. Azimsulfuron applied plots had the lowest value for these parameters. Among the growth indices LAI showed significant reduction irrespective of the herbicide throughout the growth stages as compared to Hand weeded control. The biochemical parameters such as nitrate reductase enzyme activity, phenol content, total soluble protein content and total amino acid content showed an initial decline when estimated one week after application of herbicide but by the time of flowering all the herbicide treated plants showed recovery. However the recovery was higher for Bispyribac sodium in the ALS inhibiting group and Cyhalofop in the ACCase inhibiting group. Proline content and catalase enzyme activity showed increase with herbicide application as compared to Hand weeded control indicating that application of these chemicals may be imparting stress to the plant, however by flowering time in most of the treatments there was recovery. Among the treatments, plants in the Almix and Azimsulfuron applied plots showed less recovery. The physiological parameters such as chlorophyll content, photosynthetic rate, stomatal conductance and IAA content showed decline when estimated one week after herbicide application. . In the case of chlorophyll content the recovery of the plant was comparatively less as compared to all other chemical constituents. Azimsufuron and Almix application contributed to maximum reduction in these constituents. Weed count and weed dry weight was taken on 60 DAS. The lowest values were recorded in Bispyribac sodium treatment. Azimsulfuron also a broad spectrum herbicide, was found less effective in the present study compared to Bispyribac sodium. In the present study, 5 to 17 percent reduction in grain yield and 6 to 17 percent reduction in straw yield of rice was observed by herbicide application. Among the ALS enzyme inhibitors, the lowest reduction in grain and straw yield was observed in Bispyribac sodium treatment and maximum reduction was in Azimsulfuron treatment. Among the ACCase enzyme inhibitors, Cyhalofop butyl showed least reduction in grain and straw yield of rice while fenoxaprop showed maximum reduction.ThesisItem Open Access Physiological, anatomical and molecular analysis of coconut palms (Cocos nucifera L.) affected with yellowing.(Department of Plant Physiology,College of Agriculture, Vellayani, 2011) Deepa, S; KAU; Manju, R VKerala the ‘Land of coconut’ occupies first position in area and production of coconut in India but the productivity is below the national average. This is because of unproductive and senile palms, lack of adaptation of recommended cultivation practises and serious incidence of pests and diseases. The root (wilt), an endemic disease of Kerala causes an annual loss of 968 million nuts. Recently another type of yellowing characterised by mid whorl yellowing shedding of immature nuts and drying of inflorescence without showing characteristic ribbing symptom is rapidly spreading in many parts of Kerala. There is no research report available in this emerging problem in the coconut growing tracts of Kerala. Since there is rampant spreading of yellowing to other coconut cultivated areas causing a serious reduction in nut yield, this problem demands immediate attention. Hence an experiment was conducted in the Department of Plant Physiology, College of Agriculture, Vellyani to generate the basic information on the causative agents and on the changes of physiological, molecular and anatomical realms of coconut affected by mid whorl yellowing. A wide variation was observed in the physiological parameters like total pigments, relative water content, carbohydrate fractions, proteins, phenols and antioxidants betweenpalms with yellowing and control palms. The palms with yellowing showed a significant reduction in the total chlorophyll, chlorophyll a, chlorophyll b and carotenoid content when compared to the healthy palm. Relative water content was lower for all the palms with yellowing compared to the control palm and the healthy palms were maintaining a better water status and membrane integrity. All the selected palms with yellowing recorded an accumulation of reducing sugars compared to the healthy palms. The trend was similar for starch content except for palms with general yellowing. The control palms recorded maximum protein content compared to other palms with yellowing. A significant increase in the phenolic compounds was observed in palms with yellowing compared to the healthy palms. This results point to an activated defense system. The 14th leaf starting from the first fully opened one is the most widely used leaf for nutrient analysis as recommended by the IRHO. (Fremond et al., 1966).The 14th leaf data from the control palms and palms with different types of yellowing were analysed. The data showed that there were significant reductions in the levels of major nutrient nitrogen, phosphorus and also in the levels of magnesium and the micronutrient manganese in case of palms showing mid whorl yellowing compared to the control palm. But significantly higher levels of accumulation were found in case of potassium, calcium, iron and copper. These variations in the nutrient levels can have an influence on symptom development in coconut palms. The maximum yield was recorded for the control palm. Chlorophyll degradation and loss of structural integrity were evident from the anatomical studies of leaf tissues in case of palms with yellowing. Vascular browning which extended to the cortex and the vascular disintegration in the roots of affected palms were seen on anatomical analyses. A pure quality DNA was obtained by modified CTAB DNA isolation protocol. Molecular analyses using nested PCR showed that with the phytoplasma specific universal primers P1/P7-R16F2n/R16R2 provided an amplicon ) in the positive control and palms with inner and middle whorl yellowing and the primers R16mF2 /R16mR1 -R16F2n/ R16R2 provided an amplicon for the positive control and palms with inner, middle and general yellowing. The root (wilt) phytoplasma specific semi- nested primers IF7/7R3- IF7/7R2 provided an amplicon of 493 bp only for the positive control and no amplification was seen in any of the selected palms. The control palm and the palms affected with outer whorl yellowing provided no amplification at all for any of the primers tested. Amplification of phytoplasma specific universal primers in palms with mid whorl yellowing indicates that phytoplasma has got a role in development of the specific symptom. This demands immediate attention and extensive studies on the etiology, changes in biochemical profile, anatomy etc. Salient Findings Amplification of phytoplasma specific universal primers in palms with mid whorl yellowing indicates that phytoplasma has got a role in development of the mid whorl yellowing symptom. But in case of the root (wilt) phytoplasma specific primers, there was no amplification in palms with mid whorl yellowing. This suggests that the mid whorl yellowing of coconut palm which is an emerging problem in Kerala may not be associated with the root (wilt) disease. The results of biochemical and physiological analyses of the selected palms clearly indicate an altered primary metabolism, source-sink relation and a complexity in the nutriophysiology. These altered conditions can act as predisposing factors for the development of specific symptoms. The anatomical analyses showed damages of roots in the palms with mid whorl yellowing. They will have internal browning of vascular elements, extending into the cortex and also disintegration of vascular elements. Future line of work Detailed analysis of nutriophysiology, source-sink relation and hormonal profile. Studies on soil factors like nutrient level and water status. Extension of anatomical studies to different type of tissues. Extension of molecular studies into identification of specific phytoplasmal strains associated with mid whorl yellowing of coconut palms. Development of management strategy for the improvement of the field performance and productivity of coconut palms with mid whorl yellowing.ThesisItem Open Access Physiological, phytochemical and molecular studies on abiotic stress mediated antioxidant accumulation in Amaranthus spinosus Linn.(Department of Plant Physiology, College of Agriculture, Vellayani, 2014) Garggi, G; KAU; Roy, StephenThe study entitled “Physiological, phytochemical and molecular studies on abiotic stress mediated antioxidant accumulation in Amaranthus spinosus Linn.” was conducted during the period 2012-14 in the Department of Plant Physiology, College of Agriculture, Vellayani, Thiruvananthapuram. The objective of the study was to elicit information on the physiological, biochemical and molecular attributes associated to the antioxidant accumulation due to abiotic stress factors viz. light stress and water deficit stress and CO2 enrichment in Amaranthus spinosus Linn. The study was conducted as two separate experiments. One experiment was laid out in pot culture at Instructional Farm Vellayani, in Completely Random Design (CRD) with nine treatments which included combinations of three levels of water deficit stress and three levels of shade stress in three replications. The second experiment was laid out in Open Top Chamber (OTC) in CRD with six treatments which included combinations of CO2 enrichment and two levels of water deficit stress in four replications. The observations on growth parameters revealed a general increase in plant height under shaded condition. Leaf area was maximum for plants under 50% FC and 25% shade, T6 (42.663 cm2) and plants under 50% FC and 50% shade, T3 (40.567 cm2). The results of physiological observation showed maximum concentration for total chlorophyll for plants under 50% FC and 25% shade, T6 (1.947 mg/g of leaf tissue). The analysis of biochemical parameters showed the plants under 25% shade + 100% FC (T4) and plants under open condition + 50% FC (T9) had maximum starch content of 8.963 mg/g and 8.49 mg/g respectively. The results of enzymatic antioxidant assays showed Superoxide dismutase activity was higher for plants under treatments T9 (Open + 50% FC) and T3 (50% shade + 50% FC); 0.032 Units. The non-enzymatic antioxidant assays showed the maximum Ascorbic acid content of 3.6mg/g for treatment T1 (50% shade +100% FC) and Vitamin A content was maximum for T3 (50% shade +50% FC). Total flavonoids recorded highest in plant under treatment T2 (50% shade+75 % FC) whereas total phenol was maximum for the treatment T7 (Open + 100% FC).CO2 enrichment has no significant effect on plant height. Stomatal conductivity was significantly low for CO2 enriched plant under 100% FC (25.35 m moles s-1 for OT1) and 50% FC (21.8 m moles s-1 for OT2). Plants under CO2 enrichment and 50% FC showed maximum Catalase activity (0.169 Units).CO2 treatment did not show a significant variation with respect to antioxidants. Expression level study of the gene CHS (Chalcone synthase) revealed overexpression of the gene under abiotic stress, especially under moderate shade stress. Hence the plant can be exploited for its therapeutic value and can be cultivated as an intercrop in plantations.ThesisItem Open Access Effect of UV-B radiation on physiological and phenological plasticity in rice (Oryza sativa L.)(College of Horticulture, Vellanikkara, 2015) Wagh, Yogesh Sahebrao; KAU; Nandini, KA global depletion of the stratospheric ozone layer, largely due to the release of pollutant such as chlorofluorocarbons (CFCs) caused by human activities, has resulted in an increase of solar Ultraviolet-B (UV-B) radiation in the range of 280-320 nm at the earth’s surface. Elevated UV-B exposure causes temporary or irreversible damage to plant growth and development. Though UV-B is only a minor component of total solar radiation (less than 0.5%), due to its high energy, its potential for causing biological damage is very high. UV-B radiation is highest in tropical region where rice is grown as the major food crop in these regions. Decline in rice yield during puncha season (Dec-March) gives an indication on the effect of UV-B radiation on rice yield. Failure of rice crop in puncha season has lead to abandoning of double cropping in productive rice ecosystem like kole lands of Kerala. This needs detailed investigations to come up with realistic recommendations to overcome such situations. Therefore, the present study was conducted to understand the effect of UV-B radiation on morphological, physiological, phenological and biochemical changes in rice (Oryza sativa L.). The experiment was conducted in pot culture during December 2013-April 2014, with two varieties Jyothi and Uma under three different levels of UV-B radiation i.e. - natural solar UV-B condition where crops were exposed to 100% natural solar radiation (T1), reduced UV-B radiations using UV-B Mylar film which measures UV-B as zero (T2) and 85% ambient radiation including UV-B + UV-B supplemented with UV-B lamps in polyhouse (T3). The results indicated that UV-B radiation, in the range of 1.30 to 3.58 Wm2, during the study period affected the productivity of the crop. There was significant variation in UV-B radiation from 10 am to 4 pm in all the months throughout the growing period and the maximum value was recorded during the month of March, 2014. The highest crop yield was recorded in UV-B excluded condition (T2). This was due to more No. of spikelet per panicle, filled grain per panicle and 1000 grain weight. High photosynthetic rate, stomatal conductance and more canopy cooling at both vegetative and reproductive phases, along with more IAA content, total chlorophyll and chlorophyll ‘a’ have contributed the high yield in T2 condition. The increase in physiological parameters like photosynthetic rate, stomatal conductance and canopy cooling; morphological traits like flag leaf angle and panicle length and biochemical constituents like Chlorophyll ‘a’, total chlorophyll and IAA content observed under UV-B excluded condition (T2) positively favoured the high yield and harvest index in the present study. Though the crop grown under natural solar radiation expressed more No. of productive tillers per hill, it could not produce more No. of spikelet and filled grain per panicle. Instead it produced more amount of flavanoid and phenol content by channelizing the photo assimilates at flowering stage. The phenophases of the crop like days to heading, 50% flowering and days to harvestable maturity were delayed by 4-5 days under open condition (T1).The varieties Jyothi and Uma could not produce significant difference in yield. In the present study decrease in yield and yield attributes were observed due to the current level of natural solar UV-B radiation. The UV-B radiation under open condition restricted filling of grain and further grain development leading to lesser number of filled grains per panicle and thousand grain weight.
