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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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2014 - 201930
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Subject: Plant Physiology × Author: KAU × End date: 2019 × Start date: 2012 × Thesis Type: M.Sc ×
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Now showing 1 - 9 of 30
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    ThesisItemOpen 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, K
    Sun 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.
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    ThesisItemOpen Access
    Effect of foliar application of selected micronutrients and growth regulators on tuber development , yield and fortification status of sweet potato (Ipomoea batatas L.).
    (Department of Plant Physiology , College of Agriculture,Vellayani, 2019) Arya, S R; KAU; Viji, M M
    A field experiment entitled “ Effect of foliar application of selected micro nutrients and growth regulators on tuber development, yield and fortification status of sweet potato (Ipomoea batatas L.)” was conducted at the Instructional farm, College of Agriculture, Vellayani during the period 2017-2019 with an objective to enhance the qualitative and quantitative attributes in sweet potato (Ipomoea batatas L.). Foliar application of selected micronutrients and growth regulators were carried out to study their effect on growth, development and changes in fortification status of sweet potato tubers and leaves. The sweet potato variety used for the experiment was Bhu Krishna. The technical programme consisted of 17 treatments and 3 replications with the design simple RBD. The treatments were C1 : NPK (as per POP) , C2 : NPK (as per POP) with water spray, T1 : C1+ FN (MN mixture( * ) 0.01% each , T2 : C1+ FN (MN mixture( * ) 0.05% each , T3 : C1+ FN (MN mixture( * ) 0.1% each , T4 : T1+ Ethrel 250 ppm , T5 : T1+ Ethrel 500 ppm , T6 : T1+ CCC 250 ppm , T7 : T1+ CCC 500 ppm , T8 : T2+ Ethrel 250 ppm , T9 : T2+ Ethrel 500 ppm , T10: T2+ CCC 250 ppm , T11: T2+ CCC 500 ppm, T12: T3+ Ethrel 250 ppm , T13: T3+ Ethrel 500 ppm , T14: T3+ CCC 250 ppm and T15: T3+ CCC 500 ppm [*MN mixture (Zn+Fe+B+Mn)]. Except C1, for all other treatments foliar sprays were given 3 times ie. at 30 days interval(30 DI). All the biometric and physiological parameters were taken at 25th,50th,75th and 100th days after planting and the quality parameters were taken at harvest. The results revealed that the micronutrients and growth regulators had significant influence on most of the biometric parameters, physiological parameters as well as quality parameters. Tuber characters such as tuber length, tuber diameter, tuber weight and tuber yield were found to be best in plants under the treatment T15 (T3+ CCC 500 ppm at 30DI) and it was on par with T13(T3+Ethrel 500ppm). Branch length (155.50cm), shoot weight (612 g) and specific leaf area (389.44 cm2 g-1) were found to be best in plants under the treatment T3(C1+ FN (MN mixture( * ) 0.1% each at 30DI). Number of leaves also were found to be higher in T3 (91.33) and it was on par with T2, T13 and T15. Cycocel and ethrel are growth retardants and they were found to have dwarfing effect on plants and hence shoot length and shoot weight did not increase in the treatments, T15(T3+ CCC 500at 30DI) and T13(T3+ Ethrel 500 ppm at 30DI) and on the other hand the number of leaves got positively influenced in both these treatments T15 and T13. Except transpiration rate all physiological parameters viz., total chlorophyll content (2.25 mg g-1), caroteinoid content (0.87mg g-1), stomatal conductance (131.33 mmole H2O m-2 s-1), photosynthetic rate (4.49 µmole CO2 m-2 s-1) and water use efficiency (5.35 mmol CO2 mol-1 H2O) were found to be best in plants under the treatment T15 (T3+ CCC 500 ppm) and T13 was on par with T15 in all these physiological parameters studied. Mineral constituents; N (0.614 %), P (0.056%), K (0.489%),Fe (16.30 mg kg-1), Zn (15.07 mg kg-1), Mn (7.37 mg kg-1) and B (1.27 mg kg-1) as well as other quality parameters like total phenol (13.33mg g-1), total sugar (34.48 mg g-1) and protein content (38.40mg g-1) were found to be higher in tubers under the treatment T15 (T3+ CCC 500 ppm) followed by treatment T13 which is considered as the second best treatment with respect to mineral content in tubers. Overall, the combined treatments of micronutrients along with growth regulators were found most effective in influencing quality parameters. Treatment T15 (ie.,NPK as per POP along with foliar nutrition of micronutreint mixture (Fe+Zn+Mn+B @ 0.1% each ) + cycocel (500ppm) at 30 days interval ) was found to be the best in terms of improving both the quantitative and qualitative attributes in sweet potato. Hence it is concluded that the treatment T15 improved the growth and development of plants, physiological parameters of leaves, tuber yield as well as fortification status of sweet potato tubers. Thus this study helped in identifying the best treatment combination of micronutrients and growth regulators for improving growth, development, yield and fortification status in sweet potato.
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    ThesisItemOpen Access
    Developing high temperature tolerance in tomato (Solanum lycopersicum L.) through selective fertilization technique
    (Department of Plant Physiology, College of Agriculture, Vellayani, 2019) Ammu, Alphonsa John; KAU; Roy Stephen
    The study entitled “Developing high temperature tolerance in tomato (Solanum lycopersicum L) through selective fertilization technique”, was undertaken with the objectives to identify the critical temperature for pollen germination and to evaluate the selectively fertilized tomato hybrids for high temperature tolerance at the Department of Plant Physiology, College of Agriculture, Vellayani during 2017-2019. The first experiment was designed for the identification of critical temperature for pollen germination using five popular varieties of tomato namely Anagha, Vellayani Vijay, Manuprabha, Manulakshmi and Akshaya. Mature pollen grains from fully opened flowers were collected and incubated at different temperatures (340C to 440C) for two hours in the pollen germination medium. The design followed was CRD with 4 replications. The temperature of 36oC was identified as the critical temperature for pollen germination. Anagha and Manuprabha exhibited the highest (29.69 %) and the least (11.48 %) pollen germination percentage respectively at this critical temperature. Pollen viability decreased with increase in temperature in all the five varieties. For the second experiment, the variety Anagha with the highest pollen germination at critical temperature was selected as tolerant (male parent) and the variety Manuprabha with least pollen germination at critical temperature was selected as the susceptible (female parent). Selective fertilization (SF) was done between Anagha and Manuprabha by pollinating the emasculated female parent with 2hr incubated pollen from male parent at critical temperature. Another set of cross was also made with same parental combination without pollen selection. The six crosses were made are Tolerant X Susceptible, Tolerant X Susceptible (SF), Tolerant X Tolerant, Tolerant X Tolerant (SF), Susceptible X Susceptible and Susceptible X Susceptible (SF). The seeds were collected from crosses and sown. The seedings were maintained at ambient temperature for 30 days and then transplanted in pots and exposed to three different temperature conditions ie, at ambient temperature condition, Rainout shelter (ROS) and Open top chamber (OTC) to evaluate the growth performance of the crosses. The observations were taken at 30 and 60 days after transplanting. The experiment was laid out with 18 treatments in CRD with four replications. Plant height and floral characters (number of flower clusters and number of flowers per cluster) were increased significantly with increase in temperature. Among the crosses, T15 recorded taller plants (127.32 cm). Selectively fertilized plants produced significantly more number of flowers per cluster than the normal crosses and T12 recorded maximum (11.00). However, the number of cluster was significantly higher in normal crosses and T15 had maximum number of cluster (45.50). Percentage of flowers with exerted stigma and length of stigma exertion were increased significantly with increase in temperature but the selectively fertilized crosses recorded lower stigma exertion. T15 showed the highest percentage stigma exertion (87.50%) which was at par with T3, T6, T9, T12 and T18. The length of exerted stigma was highest in T15 (2.50mm). Physiological parameters like photosynthetic rate, chlorophyll content, total soluble protein and relative water content decreased significantly with increase in temperature and the selectively fertilized crosses showed higher value than the normal crosses under higher temperature. The photosynthetic rate (17.40 µmol CO2 m-2 s-1) and chlorophyll content (1.91 mg g-1) was recorded higher in T7 which was at par with T1, T4, T10 and T11. In case of total soluble protein there was no significant difference. The relative water content was highest in T4 (74.80%) but at par with T1, T7 and T10. Carbohydrate content decreased with increasing temperature and among the crosses selectively fertilized plants showed significantly higher content. The carbohydrate content was the highest in T8 (79.62 mg g-1) but at par with T5. Temperature tolerance characters like membrane integrity (% leakage), SOD activity and chlorophyll fluorescence were higher in selectively fertilized plants than the normal plants. The percentage leakage increased with increase in temperature and T10 had the least leakage (1.40 %). The SOD activity first decreased and then increased with temperature and T5 exhibited maximum SOD activity (337.50 activity mg-1 min-1) which was at par with T2 and T8. The chlorophyll fluorescence significantly decreased with increase in temperature, the maximum fluorescence recorded in T4 (0.65 fv/fm) which was at par with T1, T7, T10, T16 and T5. Ascorbic acid content of leaves increased significantly with increase in temperature but decreased under OTC. T5 (464.65 µg g-1) and T18 were on par with respect to ascorbic acid. The yield characters like number of fruits, fruit setting %, fruit weight and lycopene content were high in selectively fertilized crosses than the normal crosses. The yield characters decreased significantly with increase in temperature and there was no fruit set at OTC due to very high temperature. T10 recorded highest number of fruits per cluster (6) which was at par with T7 and T1. The fruit setting percentage was the highest in T7 (89.29%) which was at par with all treatments except T2 and T14. The fruit weight increased in ROS condition compared to ambient condition and the highest fruit weight was recorded in T17 (37.77g) which was at par with T16, T5 and T14. Highest lycopene content was recorded in T10 (24.86 µg g-1). The yield was decreased significantly with increase in temperature and the highest yield was obtained in T4 (402.15 g plant-1) which was at par with T4, T7 and T10. Critical temperature for pollen selection and selective fertilization was selected as 360 C. Anagha exhibited higher germination percentage and pollen viability at critical temperature among the five varieties of tomato tested and Manuprabha had the least pollen germination. Selective fertilization technique was found to have an advantageous influence on the physiological and yield attributes as it increased the photosynthetic efficiency and high temperature stress tolerance. Selective fertilization of cross of tolerant and susceptible parent TXS (SF) was found to be the best performing type under high temperature condition.
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    ThesisItemOpen Access
    Impact of foliar application of plant growth regulators and nutrients on high temperature stress mitigation in rice (oryza stavia L)
    (Department of Plant Physiology, College of Agriculture,Vellanikkara, 2019) Raghunath, M P; KAU; Beena, R
    The study entitled “Impact of foliar application of plant growth regulators and nutrients on high temperature stress mitigation in rice (Oryza sativa L.)” was conducted in the Department of Plant Physiology, College of Agriculture, Vellayani during August to December of 2018 with the objectives to study the effect of foliar application of plant growth regulators and nutrients on high temperature mitigation and to advance the flowering time by using methyl jasmonate (MeJA) in rice. The investigation comprised two experiments. The extent of variation for various physiological, biochemical, morphological and yield parameters were assessed as an indicator of high temperature stress mitigation by using plant growth regulators and nutrients. The rice variety (Uma) utilized in the experiment was collected from IFSRS, Karamana. Plants were maintained under high temperature condition in a temperature controlled polyhouse from seedling to maturity stage with three replications. Maximum and minimum temperatures were measured daily using a thermo-hygrometer. The first experiment was laid out in CRD with 10 treatments [Brassinosteroid (BR)-50 ppm, Boron (B)-100 ppm, Calcium chloride (CaCl2)-0.6 per cent, Salicylic acid (SA)-50 ppm, Glycine betaine (GB)-20 ppm, Pink- Pigmented Facultative Methylotrophs (PPFM)-1 per cent, 1-methyl cyclopropane (1-MCP)-50 ppm, Gibberllic acid (GA3)-50 ppm, water spray and control (no spray)] were sprayed at panicle initiation, heading and flowering stage. Physiological observations and yield parameters were recorded at 50 per cent flowering and harvesting stage respectively. The study revealed that physiological and biochemical parameters such as cell membrane stability index (%), photosynthetic rate (μmol CO2 m-2 s-1), stomatal conductance (mmol H2O m-2 s-1) and Fv/Fm ratio were found to increase significantly in most of the treatments under high temperature stress condition, whereas leaf temperature(°C) and transpiration rate (mmol H2O m-2 s-1) decreased. Among the treatments, BR spray significantly increased in the cell membrane stability index (141.57%), photosynthetic rate (17.50 μmol CO2 m-2 s-1), stomatal conductance (583.70 mmol H2O m-2 s-1), Fv/Fm ratio (0.74), chlorophyll stability index (109.32%), chlorophyll a/b ratio (1.28) and superoxide dismutase activity (0.33 activity g-1 min-1). Treatments had significant effect on morphological and yield parameters over control plants. Among the treatments, GA3 spray resulted in significant increase in plant height (142.75 cm) and panicle length (21.33 cm). BR spray significantly increased the productive tillers per plant (10.25), pollen viability (80.23%), spikelet fertility percentage (75.4%) and grain yield per plant (15.87 g). The second experiment was laid out in CRD with 10 treatments. Foliar spray of MeJA in varying concentrations was given on spikelet at different time [2mM L-1 MeJA at 7 am, 2mM L-1 MeJA at 8 am, 2mM L-1 MeJA at 9 am, 4mM L-1 MeJA at 7 am, 4mM L-1 MeJA at 8 am, 4mM L-1 MeJA at 9 am, water spray at 7 am, water spray at 8 am, water spray at 9 am and control (no spray)]. Physiological observations were taken at 50% flowering stage and yield parameters were taken at harvesting stage. The study revealed that among the treatments, 4mM L-1 MeJA at 7 am treatment showed early anthesis (08:11 am) and also significant increase in pollen viability (61.93%), spikelet fertility (56.07%), yield per plant (8.55 g) and 1000 grain weight (21.33 g). In the first experiment there was significant variation for physiological, biochemical, morphological and yield components among treatments. BR treatment recorded high pollen viability, spikelet fertility and grain yield per plant by improving the physiological and biochemical traits such as cell membrane stability index, photosynthetic rate, stomatal conductance, Fv/Fm ratio, chlorophyll stability index, chlorophyll a/b ratio and superoxide dismutase activity. Hence, BR treatment can mitigate the ill effects of high temperature stress in rice. In the second experiment there was significant variation for physiological and yield components among treatments. 4mM L-1 MeJA at 7 am showed better performance for all the parameters such as anthesis time, pollen viability, spikelet fertility, yield per plant and 1000 grain weight. Hence, MeJA can advance anthesis time thereby enabling plants to escape from the severe temperature experienced at normal flowering time.
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    ThesisItemOpen 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 Stephen
    Plant 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.
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    ThesisItemOpen Access
    Validation of temperature induction response (TIR) technique for inducing drought and heat stress tolerence in rice (Oryza sativa L.)
    (Department of Plant Physiology, College of Agriculture, Vellayani, 2018) Reshma Mohan; KAU; Beena, R
    The experiment entitled “Validation of Temperature Induction Response (TIR) technique for inducing drought and heat stress tolerance in rice (Oryza sativa L.)” was undertaken at the Department of Plant Physiology, College of Agriculture, Vellayani during 2016-18. The objective of the study was to standardize TIR protocol for rice and to study the effect of TIR technique for combined drought and heat stress tolerance in rice. The investigation comprised of two experiments. In the first experiment, two rice varieties namely Jyothi (Ptb-39) and Vaishak (Ptb-60) were used for the standardization of lethal and induction temperature and in the second experiment ten rice genotypes (N22, Apo, CR Dhan 305, CR Dhan 307, Ptb-7, Ptb-15, Ptb-30, Ptb-39, Ptb-43 and Ptb-60) were used to study the effect of TIR technique on combined drought and heat stress tolerance. In the first experiment 13 different treatments (T1-3: 49°C for 2, 2½ and 3 h, T4-6: 50°C for 2, 2½ and 3 h, T7-9: 51°C for 2, 2½ and 3 h, T10-12: 52°C for 2, 2½ and 3 h, T13: control) were used to identify lethal temperature and induction temperature was standardized from four treatments (T1- 28-40 ºC for 5 h & 40-52 ºC for 30 min, T2- 32-40 ºC for 5 hr & 40-52 ºC for 30 min, T3- 32-42 ºC for 5 h & 42-52 ºC for 30 min, T4- Control) with three replications. In the first experiment 100% mortality was observed for the treatment 52°C for 3 h and was selected as lethal temperature. Maximum recovery growth and least percent reduction in recovery growth were observed under T3 (32-42 ºC for 5 h & 42-52 ºC for 30 min) and this treatment was selected as induction temperature. The second experiment was laid out with 8 treatments [T1- TIR treated seeds + Drought + Heat, T2- TIR treated seeds + Drought, T3- TIR treated seeds + Heat, T4- TIR control,T5-Germinated seeds under ambient temperature + Drought + Heat, T6-Germinated seeds under ambient temperature + Drought, T7-Germinated seeds under ambient temperature + Heat, T8- Control (Ambient temperature + Normal irrigation)] and three replications. Among the genotypes, Ptb-15 recorded the highest plant height, shoot dry weight, root length and root volume. Leaf area was maximum for Ptb-43 and Apo recorded maximum root dry weight. Minimum canopy temperature was shown by N22 and Ptb-7. The genotype N22 showed the highest mean values for cell membrane stability index, chlorophyll stability index, stomatal conductance, photosynthetic rate, proline content, peroxidase activity, spikelet fertility and pollen viability. Early flowering and minimum days to 50% flowering also were recorded in N22. Productive tiller number was highest in Ptb-7 and 1000 grain weight was maximum for Ptb-43. The highest SOD activity was observed in Ptb-15. Ptb-39 (Jyothi) showed the minimum values for most of the stress related traits and yield components under various stress conditions and hence this genotype is selected as the most susceptible genotype towards both drought and heat stress conditions. Among the treatments, T4 (TIR Induced plants without stress) recorded maximum value and T5 (non-induced plants under combined drought and heat stress) recorded minimum value for all the above mentioned morphological characters except root length. Maximum root length was recorded in T2 (induced plants under drought) and minimum in T8 (control). Peroxidase and SOD activity were highest in T2 and minimum for T5. Maximum value for yield related traits were observed for T4. Plants under combined drought and heat stress without induction showed minimum value for all the physiological and yield parameters. The results of the present study showed that TIR technique influenced all the genotypes at various stress levels. TIR induced plants exhibited better performance on biochemical and physiological traits than non-induced plants in all the genotypes that give rise to better stress tolerance. N22 and Apo were selected as the best genotypes for stress related traits. Apart from these two, Ptb-15, Ptb-7 performed better under heat stress and drought respectively. For combined stress, Ptb-30 and Ptb-15 were showed better performance compared to other genotypes. Ptb39 was identified as the most susceptible genotype for both drought and heat stress. TIR induced and non-induced plants of Ptb-39 (most susceptible) and N22 (tolerant) were selected to study the changes in protein profiling and gene expression level using SDS PAGE and RT PCR. The results revealed that protein profiling showed variation between tolerant and susceptible genotypes under induced and non-induced condition for the expression of 20 kDa and 75 kDa protein. Expression level of PSTOL1 and DRO1 also showed variation between induced and non-induced plants of tolerant and susceptible genotypes. Protein synthesis was maintained significantly higher in the induced plants compared to non-induced plants on being exposed to severe stress. Tolerance of genotypes towards stress has been attributed to changing transcript levels of stress induced genes. In the present study, T3 (32-42°C for 5 hrs & 42-52°C for 30 minutes) and T12 (52°C for 3 hrs) were selected as the induction and lethal temperatures respectively. The study also revealed that TIR technique can be used as a potential tool for improving the performance of high yielding susceptible genotypes under stress conditions.
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    ThesisItemOpen Access
    Physiological studies on growth , yield and quality enhancement of chilli (Capsicum annuam L.) under different nutrient management
    (Department of Plant Physiology, College of Horticulture, Vellanikkara, 2019) Amrutha, E A; KAU; Sudarsana Rao, V
    Chilli is a very important vegetable crop and has a great demand in the processing industry and export market. Chilli crop is more responsive to fertilizer application. Application of fertilizers in excess not only causes environmental problems but also reduces nutrient use efficiency, increases the cost of production and reduces the benefit-cost ratio. Nanotechnology is a newly emerging tool for solving these problems. Nano fertilizer has a particle size less than 100 nm. Due to its small size and water soluble nature it is easily absorbed by plants. The present study was carried out to understand the influence of soil and foliar application of nano NPK fertilizer and to compare with conventional fertilizers on growth, yield and quality attributes of chilli. The investigation on “ Physiological studies on growth, yield and quality enhancement of chilli (Capsicum annum L.) under different nutrient management ” was conducted at Regional Agricultural Research Station, Pillicode from September, 2018 to February, 2019. The experiment consisted of nine treatments with three replications laid out in randomized block design. The treatments were T1 : Control (soil test based nutrient management); T2 : Nano NPK granules (4:4:4); T3 : T1 + Nano NPK foliar @ 0.5 %; T4 : T1 + NPK 19:19:19 foliar @ 0.5 %; T5 : T2 + Nano NPK foliar @ 0.5 %; T6 : T2 + NPK 19:19:19 foliar @ 0.5 %; T7 : Organic POP (KAU, 2009); T8 : Organic POP + Nano NPK foliar @ 0.5 % and T9 : Absolute control. Nano NPK granules were applied as a basal dose and also as top dressing at 30 and 60 days after transplanting @ 0.33 g/plant. Foliar spray of Nano NPK and NPK 19:19:19 were given at 35, 65, 80 and 95 days after transplanting. Morphological observations namely plant height, leaf area per plant, number of leaves per plant, number of branches per plant, number of fruits per plant and fruit length were recorded to be maximum in the treatment, nano NPK granule with NPK 19:19:19 foliar spray (T6) followed by nano NPK granule with nano NPK foliar spray (T5). Integrated use of nano NPK granules with nano NPK foliar spray application (T5) enhanced the duration of crop and increased the root volume followed by T6 . Higher values of growth indices such as RGR, LAI and total dry matter production was observed in T6 (nano NPK granule and NPK 19:19:19 foliar spray) followed by T5 (nano NPK granules with nano NPK foliar spray). Physiological parameters such as transpiration rate, stomatal conductance, chlorophyll content, leaf relative water content, specific leaf weight, quantum yield (Y(II)), Fv/Fm and electron transport rate (ETR) were statistically on par in all the treatments and was significantly higher than absolute control (T9). Differential application of NPK 19:19:19 foliar spray (T6) and nano NPK foliar spray (T5) along with nano NPK granules increased the fruit yield by 28.07 % and 26.54 % respectively over control (T1). Organic management (T7) alone and organic management with nano NPK foliar spray (T8) recorded 25.54 % and 16.04 % lesser fruit yield than control (T1). However fruit quality parameters like ascorbic acid and oleoresin contents were maximum in the treatment receiving an organic management with a foliar spray of Nano NPK (T8). Maximum benefit cost ratio (1.73) was recorded in treatment T6 (nano granule with 19:19:19 foliar spray) followed by treatment T5 (nano granule with nano NPK foliar spray (1.61) compared to other treatments. The results obtained from the experiments indicated that the application of nano NPK fertilizer both as soil and foliar treatments has a direct positive effect on morphological and yield parameters, which is on par with the treatment involving soil application of nano NPK granules and NPK 19:19:19 foliar spray.
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    ThesisItemOpen Access
    Influence of CO2 enrichment and associated high temperature on reproductive physiology of tomato (Solanum Lycopersicum L)
    (Department of Plant Physiology, College of Agriculture, Vellayani, 2019) Lakshmi G Ajay; KAU; Manju, R V
    The study entitled “Influence of CO2 enrichment and associated high temperature on reproductive physiology of tomato (Solanum lycopersicum L.)”, was undertaken with the objective to study the effect of CO2 enrichment and associated high temperature on flowering and fruiting in tomato and their improvement through growth regulators and nutrient applications and through temperature induction response technique. The experiments were conducted using the Open Top Chamber (OTC) facility at the Department of Plant Physiology, College of Agriculture, Vellayani during 2017-2019. The first part of Experiment I was designed for the standardization of Temperature Induction Response Technique (TIRT) for two popular varieties of tomato namely Vellayani Vijay and Anagha by identifying lethal and induction temperatures. Five day old tomato seedlings grown in petri plates were exposed to different temperatures (35-50 0C) for different durations (1h to 2h). The temperatures of 48oC for 2 h and 38oC (1h)- 43 oC (1h)- 48 oC (2h) proved to be the lethal and induction temperatures respectively for both the varieties based on the recovery responses. In the second part of Experiment I growth performance of temperature induced seedlings of variety Vellayani Vijay was evaluated under elevated CO2 (500 ppm) and ambient conditions. The experiment was laid out in CRD with four replications. Growth parameters like plant height, number of branches and number of leaves were not significantly affected by temperature induction but significantly higher value was recorded in the case of specific leaf area (283.50 cm2 g-1) compared to control (261.83 cm2 g-1). Among the physiological and biochemical parameters, temperature induction resulted in significantly higher values for total chlorophyll content (1.74 mg g-1), total carbohydrate (36.71 mg g-1), photosynthetic rate (22.13 µmol CO2 m-2 sec-1), water use efficiency (4.98 mmol CO2 mol-1 H2O), chlorophyll fluorescence (Fv/Fm) (0.82), relative water content (92.20 %), superoxide dismutase (0.21 activity g-1min-1), chlorophyll stability index (145.97 %) and proline content (1.32 µM g-1 tissue) compared to plants without induction. In the second experiment, flowering and fruiting in tomato under elevated CO2 environment, as influenced by growth regulators and nutrient applications, were evaluated. The experiment was laid out in CRD with eight treatments and three replications. The treatments comprised of 50 ppm NAA (T1), 50 ppm Salicylic acid (T2), 50 ppm Boron (B) (T3), 50 ppm Boron (B) + 50 ppm Zinc (Zn) (T4), as foliar spray (at 40,55 and 75 DAS), nutrient application of POP 125% N: 100% P: 100% K (T5), POP 125% N: 125% P: 125% K (T6), a control (water spray) (T7) and an absolute control (T8). Plant height, number of branches, number of leaves and specific leaf area were found to increase significantly under elevated CO2 condition. Among the treatments, T3 recorded taller plants (85.33 cm). However number of branches (5.50), number of leaves (46.67) were significantly higher in T5. T6 recorded significantly higher value (347.99 cm2 g-1) for specific leaf area. All the physiological and biochemical parameters except transpiration rate and total soluble protein content showed significantly higher values inside OTC. T3 significantly higher values for chlorophyll content (1.55 mg g-1) and chlorophyll stability index (124.88 %) among treatments. T5 recorded highest values for photosynthetic rate (21.62 µmol CO2 m-2 sec-1) and water use efficiency (4.67 mmol CO2 mol-2 H2O). T6 resulted in significantly higher values for chlorophyll fluorescence (0.75), relative water content (96.87 %), superoxide dismutase (0.23 activity g-1 min-1) and peroxidase (44.43 unit min-1 g-1) compared to control. Flowering was delayed under elevated CO2 condition. There was an increase in total number of flower clusters inside OTC. However a significant reduction in pollen viability (82.35 %) was noticed under elevated CO2 conditions. T3 resulted in a higher pollen viability (30.28 %) and fruit setting percentage (38.52 %) compared to control under elevated CO2 condition. Days to fruiting was found to be delayed inside OTC. T7 and T4 significantly increased the fruit weight. T5 resulted in less fruit drop leading to increased number of fruits. Yield per plant was significantly higher for T5 (190.85 g plant-1), T6 (155.21 g plant-1) and T3 (148.29 g plant-1) compared to control (61.83 g plant-1). Under elevated CO2 condition, T5, T4and T3 were found to increase the yield per plant. T3, T1 and T6 resulted in an increase in the lycopene content, thus improving quality of the fruit. In the present study, CO2 enrichment was found to have a deleterious influence on flowering and fruiting in tomato mainly due to reduced pollen viability and floral deformities. TIRT was proved to improve photosynthetic efficiency and stress tolerance mechanism. Foliar spray with 50 ppm B + 50 ppm Zn at 40, 55 and 75 DAS and addition of 25% extra nitrogen than recommended dose in equal splits were found to improve yield and quality to a great extent. This was achieved through improvement in pollen viability, fruit set and individual fruit weight and also through a reduction in fruit drop. These treatments can be exploited further, individually or in combination, in any crop management programme for tomato under increasing CO2 and associated high temperature conditions. The study also highlights a need for reassessment of critical nutrient requirements for individual crops in the changing global climatic scenario.
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    ThesisItemOpen Access
    Physiological approaches for enhancing the ex vitro establishment of tissue cultured orchid (Phalaenopsis sp.)
    (Department of Plant Physiology, College of Agriculture, Vellayani, 2019) Sayooj, S; KAU; Viji, M M
    The study entitled “Physiological approaches for enhancing the ex vitro establishment of tissue cultured orchid (Phalaenopsis sp.)” was undertaken during 2017-2019, at College of Agriculture, Vellayani, Thiruvananthapuram, with the objective to study the physiological changes that occur during ex vitro establishment of orchid Phalaenopsis sp. and to find out measures to overcome the field mortality rate and improve propagation efficiency. The experiment was laid out in completely randomized block design with three replications of ten treatments as well as a control. In vitro derived plantlets of Phalaenopsis sp. obtained from Biotechnology and Model Floriculture Centre, Kazhakuttam were used for the study. Ten treatments were T1 and T2 (plantlet dip with triazole @ 5ppm and 10 ppm respectively), T3 and T4 (plantlet dip with triazole @ 5 ppm + foliar application of triazole @ 5ppm after 15 days of planting and plantlet dip with triazole @ 10 ppm + foliar application of triazole @ 5ppm after 15 days of planting respectively) , T5 and T6 (plantlets providing with 40-50% light intensity & 60-70% humidity and 40-50% light intensity & 80-90% humidity respectively) T7 and T8 (plantlets providing with 70-80% light intensity & 60-70% humidity and plantlets providing with 70-80% light intensity and 80-90% humidity respectively) , T9 (plantlet dip of PGPR mix І -5%) , T10 (root zone application of arbuscular mycorrhizal fungi -5g/plantlet) and a control (C). The crop was maintained in the hardening chamber for 70 days and observations were taken at 15, 30,45 and 60 days of ex vitro transfer. Results revealed that growth regulators, growth stimulants, light and humidity had significant effect on physiological, morphological, biochemical, biometric and anatomical characters during the ex vitro establishment of tissue cultured orchid Phalaenopsis sp. During their ex vitro establishment, physiological parameters like specific leaf area and photosynthetic rate showed significantly higher response at all the four stages of observation, in the treatment provided with 40-50% light intensity and 80-90% humidity (T6) whereas transpiration rate was the lowest in T3 (plantlet dip with triazole @ 5 ppm + foliar application of triazole @ 5ppm after 15 days of planting and plantlet dip with triazole @ 10 ppm). Among the stomatal characters, stomatal index was not significantly affected by growth regulators, light intensity, humidity and growth stimulants. However, highest stomatal frequency was recorded in T3 (plantlet dip with triazole @ 5 ppm + foliar application of triazole @ 5ppm, after 15 days of planting). Plantlets treated with arbuscular mycorrhizal fungi (T10) recorded the highest plant height during 15 and 30 DAP. However at 45 and 60 DAP, plantlets which were provided with 40-50% light intensity and 80-90% humidity (T6) recorded the highest plant height. Number of leaves per plantlet and survival percentage were also found highest in T6. But in the treatment, T3 (plantlet dip with triazole @ 5 ppm + foliar application of triazole @ 5ppm) maximum number of roots was observed at all the four stages of observation. The results also showed that chlorophyll a and total chlorophyll content of the leaves were maximum in T3 whereas in T6, the highest chlorophyll b and carotenoid content were found at all the four stages of observation. Also T3 (plantlet dip with triazole @ 5 ppm + foliar application of triazole @ 5ppm) recorded the highest protein content and carbohydrate content. Leaf area and root length were also found to be significantly higher in T6 (plantlets provided with 40-50% light intensity and 80-90% humidity). Root shoot ratio was the highest in T9 at 15 and 30 DAP and T3 recorded the highest root shoot ratio at 45 and 60 DAP. Fresh weight and dry weight of the plantlets were recorded maximum in T10 (plantlets treated with arbuscular mycorrhizal fungi). There was no significant difference in the number of mesophyll layers of orchid leaves during the ex vitro establishment. However, cuticle thickness was found highest in T3 (plantlet dip with triazole @ 5 ppm + foliar application of triazole @ 5ppm, after 15 days). Survival percentage is considered to be the most important factor during the ex vitro establishment of tissue cultured orchids. Among the different treatments, T6 (plantlets provided with 40-50% light intensity and 80-90% humidity) recorded the highest survival percentage at all the four stages of observation (80, 76, 72, 66 percentage respectively) compared to control. Considering the physiological, morphological, biochemical, biometric and anatomical characters, treatment T6 (plantlets provided with 40-50% light intensity and 80-90% humidity) is adjudged as the best physiological approach to overcome field mortality and improve propagation efficiency of tissue cultured orchid Phalaenopsis sp. during ex vitro establishment.