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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 Physiological aspects of ex vitro establishment of tissue cultured orchid plantlets(Department Of Plant physiology, College Of Agriculture, Vellayani, 2000) Samasya, K S; KAU; Viji, M MThe present investigation was undertaken to elicit information on the physiological, morphological, biochemical, biometric and anatomical changes during in vitro propagule multiplication and ex vitro establishment in tissue cultured plantlets of orchids. Dendrobium hybrid Sonia 17 was the variety used for the study. The rooting media was supplemented with different levels of sucrose. At the time of planting the plantlets were subjected to triazole treatment. During the process of hardening the plantlets were maintained in hardening chambers with different levels of light and humidity. Among growth parameters the crop growth rate (CGR), net assimilation rate (NAR) and relative growth rate (RGR) were found to be high at 40 gIl of sucrose concentration. The CGR of these plantlets were on par with normal green house grown plantlets. The photosynthetic rate was found to increase and the transpiration rate was found to decrease at 40 gIl of sucrose . concentration. The maximum survival percentage of the in vitro plantlets occur when 40 g11 of sucrose incorporated in the rooting medium. This may be attributed to the influence of the sucrose concentration on morphological characters studied viz. plant height, number of leaves per shoot and number of roots per shoot. With regard to photosynthetic pigments an increase in the content of total chlorophyll, chlorophyll a chlorophyll b and carotenoids occurred in plantlets treated with 40 g/1 of sucrose. Also the protein content and carbohydrate content was maximum at the above sucrose level. The leaf area, root length, total fresh weight and dry weight of the plantIets maintained at 40 gIl of sucrose level were higher than other treatments. These effects ultimately lead to better survival percentage. Triazole treatment of plantIets during planting out helped in better survival percentage. With regard to the growth parameters the effect was distinct towards the later stage of growth. CG~ NAR and RGR were maximum on the triazole treated (5 mgll) plantIets and was comparable to normal green house grown plants. There was marked increase in the photosynthetic rate and decrease in transpiration rate of plantIets treated with 5 mgll of triazole. However the photosynthetic rate of normal green house grown plants were much more than the tissue cultured plantIets. Regarding morphological characters, increasing concentration of triazole had negative influence on plant height. However plant height of normal green house grown plants were distinctively higher than tissue cultured plantIets. With regard to number of leaves per shoot, triazole treatment showed significant effect only after 30 days of planting out, whereas the number of roots per shoot was very much influenced by triazole. The maximum number of roots was produced at 5mgll of triazole treatment and these effects in turn influenced higher survival percentage of plantIets. ------....- ....- ~ - - - ----- Regarding the biochemical aspects total chlorophyll, chlorophyll a, chlorophyll b and carotenoids contents of plantlets treated with triazole (5 mg/l) were higher and found to be on par with that of green house grown normal plants towards the later stage. The protein content was also positively influenced by triazole treatment (5 mgll) and the value was comparable to that of normal plantlets. In the case of carbohydrate content the treatment becomes statistically significant and the normal green house grown plants exhibited distinctively higher value. The plantlets treated with 5 mgll of triazole were found to have higher leaf area, root length, root: shoot ratio, total fresh weight and dry weight than other treatments. However the root shoot ratio and total fresh weight of treated plantlets were on par with the normal green house grown plants towards the later stage viz, 45DAP. The physiological, morphological, biochemical and biometric characters of the plantlets were also found to be influenced by different levels of light intensity and humidity maintained in the hardening chamber. Among the different treatments, plantlets grown at 50 percent light intensity and 70 to 90 percent relative humidity exhibited higher CG~ NAR and RGR. Also these plantlets exhibited a marked increase in photosynthetic rate and decrease in transpiration rate. However CGR and NAR of green house grown normal plants were distinctively higher during the later period. However the normal plants had distinctively higher CG~ RGR and photosynthetic and very less transpiration rate than other treatments. The plantlets grown under 50 percent light intensity and 70 to 90 percent humidity produced maximum plant height, number of leaves and number of roots per shoot. The survival percent of the tissue cultured plantlets in the field condition (green house) was found to be superior under appropriate environment of light and humidity (50 percent light intensity and 70 to 90 percent relative humidity) There was not much significant difference among the treatments of light and humidity in the case of pigment content. However the plantlets grown in the hardening chamber maintained at 50 percent light intensity and 70 to 90 percent of relative humidity recorded maximum value of total chlorophyll, chlorophyll a, chlorophyll b and carotenoids among treatments and the normal green house grown plants exhibited distinctively higher pigment content. The normal plantlets recorded marked increase in protein content and carbohydrate content than the tissue cultured plantlets. In the present study, an environment of 50 percent light intensity and 70 to 90 percent relative humidity was found to be superior and could favour enhanced leaf area, total fresh weight, total dry weight and root length of plantlets which ultimately resulted in better survival percentage. The in vitro plantlets observed to have anatomical characters as compared to the normal green house grown plants and hardened plantlets. The stomata remained open and less number of stomata per unit area of leaf was observed as the in vitro leaves were concerned. Another peculiarity of the in vitro plantlets was the absence of cuticle layer. The mesophyll layers were also found to be less compared to normal plantlets. These anatomical characters were one of the severe limitations of the micropropagated orchid plantlets during ex vitro establishment which ultimately resulted in high rate of field mortality.ThesisItem Open Access Influence of host plants and soil moisture stress on the water relations in sandal(Department of Tree Physiology and Breeding, College of Forestry,Vell, 2006) Dhaniklal, G; KAU; Asokan, P KThe influence of host plants and soil moisture stress on water relations in sandal was investigated in a pot culture experiment at College of Forestry, Kerala Agricultural University, Vellanikkara. Five host plants, Divi divi (Caesalpinia coriaria Jacq.), Casurina (Casuarina equisetifolia J.R & H.G. Forst), Pongamia (Pongamia pinnata (L.) Pierre), Lantana (Lantana camara L.) and Erythrina (Erythrina indica Lamk.) were selected for this study. The results showed that Sandal seedlings with and without host showed similar height increment, except when erythrina was the host. The host plant had no influence on most of the growth parameters of sandal seedlings. The collar diameter of sandal seedlings with and without host was on par during the early seedling stage and by the end of the experimental period it showed a significant difference. There was no significant difference in the number of leaves, leaf area and root length of sandal with different hosts. Haustorial connections were not recorded even after the experimental period. Sandal seedlings with Erythrina indica as host decreased the pre dawn water potential. Water stress decreased the seedling height, collar diameter, number of leaves, leaf area, shoot dry weight and total dry weight of sandal seedlings. Fully irrigating the pots once in three days resulted in better growth of sandal seedlings as compared to irrigation once in six days. Water stress increased the root length and root dry weight. Root length was found to be more for sandal seedlings which were irrigated once in six days compared to that, irrigated once in three days. Water stress decreased leaf area of sandal seedlings. Transpiration rate at 14:00 hrs was found to be more than that of transpiration at 8:00 hrs. Transpiration rate decreased with increase in soil moisture stress. Pre dawn water potential was lower for sandal seedlings irrigated once in six days compared to that irrigated once in three days. As the haustorial connections were not observed even after 270 days after planting it can be concluded that the difference in the seedling growth parameters of sandal with some of the hosts is due to the above and below ground competition for sun light, water and nutrients.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 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, RThe 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.ThesisItem Open Access Interactive effect of UV radiation and elevated temperature on rice growth and physiology(Department of Plant Physiology, College of Horticulture, Vellanikkara, 2018) Amjath, T; KAU; Girija, TRice is a staple food for more than half the world’s population. The growth and productivity of the crop is intimately associated with climatic variants. Among different climatic factors, temperature and incidence of UV-B radiation are important. The incidence of stress (Temperature and UV) at different stages of growth determines the productivity of the crop. Hence the present study was undertaken with the prime objective of evaluating the interactive effect of UV-B radiation and elevated temperature at different phenophases of Uma rice variety and its effect on growth and productivity. The study was carried out at College of Horticulture, Vellanikkara during Jan to May- 2018. The UV-B radiation and atmospheric temperature were maximum during this season. 14 days old Uma seedlings were used as plantingmaterial. It was grown under four different conditions, namely T1(10C lesser than ambient+ low UV-B), T2 (10 C higher than ambient+ low UV-B), T3 (20 C higher than ambient+ low UV-B), T4 (Open condition). The plants were kept in the polyhouses for 30 days during three phenophases of the crop viz, seedling to active tillering (P1), active tillering to early reproductive (P2) and early reproductive to harvest (P2) and returned to ambient condition to complete their life cycle. Morphological, biochemical, physiological and yield parameters were analyzed during the growth period. Exposure of plants to T1 (10 C below ambient) had least negative influence on growth, physiology and yield of the crop across different developmental stages. A 10C increase in temperature above ambient (T2) in phase 1 improved the yield and yield parameter. However the impact was negative under same condition during phase 2 (P2) and phase 3 (P3). Maximum deleterious effects were observed in T3 during phase 2 and 3. Plants grown in open condition had lower plant height and higher number of tillers as compared to plants grown in polyhouse condition (T1, T2 and T3). Number of days to heading was less in plants grown under high temperature conditions (T2 and T3). The photosynthetic rate, stomatal conductance and transpiration rate were maximum in T2 condition in all the three phases of growth. Analysis of biochemical parameters showed that the IAA content was 67 percent lesser in plants grown under open condition as compared to ployhouses during P1. Similar decrease was also found in the case of gibberellic acid and chlorophyll. Amylose content of the grain were significantly reduced in the plants grown under T2 and T3 conditions during P2 and P3. Plants exposed to temperature above ambient level (T2 and T3) during P2 and P3 stages recorded a reduction in yield. Maximum yield reduction was observed in T3 condition which was 13 percent in P2 and 56 percent in P3. Reduction in spikelets number and pollen viability were the main reasons. The study indicates that plants were most sensitive to high temperature stress during the P2 and P3 stages, which can contribute to drastic yield decline while, the early stress can have a positive influence on yield.ThesisItem Open Access Physiological and molecular analysles of flowering responses in amaranthus (amaranthus spp.) and cowpea (vigna spp.) under elevated CO2 environment(Department of Plant Physiology, College of Agriculture, Vellayani, 2018) Ghade Rameshwar, Pandurang; KAU; Manju, R VThe study entitled “Physiological and molecular analyses of flowering responses in amaranthus (Amaranthus spp.) and cowpea (Vigna spp.) under elevated CO2 environment” was undertaken with the objective to study the physiological, molecular and biochemical basis of elevated CO2 mediated modifications in the flowering responses of amaranthus and cowpea. The experiments were conducted at the Department of Plant Physiology, College of Agriculture, and Vellayani dudring 2015-2017. Two pot culture experiments were conducted with two varieties of amaranthus – Arun and CO-1 and two varieties of cowpea-Anaswara and Vellayani Jyothika. The technology used for CO2 enrichment was Open Top Chamber system (OTC). CO2 was released from cylinders to OTC bringing the CO2 level to 600ppm. Amaranthus and cowpea plants were raised and maintained in pots as per POP (KAU) recommentdations under elevated CO2. The control sets were kept under open field condition. Growth analysis and analyses of physiological and biochemical parameters were done at the time of harvest. The varieties which showed modification in flowering time to a greater extent under exposure to elevated CO2 were chosen for molecular analyses. In the case of amaranthus, CO-1 variety recorded highest values of growth, physiological and biochemical parameters and was performing better when exposed to elevated CO2 condition. CO-1 recorded highest values for number of leaves (42.44), specific leaf area (219.13), root weight (1.45g), shoot weight (3.17g), total dry matter (4.93g), stomatal frequency (595.78cm -2), pigment composition (0.56mg g-1), total soluble protein (23.02mg g-1), starch (3.61mg g-1), reducing sugar (18.46mg g-1), GA (0.198 µg g-1) and nitrate reductase (0.65 µg g-1). Flowering time was modified in CO-1 in terms of days to first flowering and days to 50% flowering (2 days); but Arun did not show any significant response in flowering time and hence CO-1 was selected for molecular analyses. Regarding quality parameters. Arun showed a reduction in ascorbic acid and vitamin A content under CO2 enrichment with an increase in oxalate content. In the case of CO-1, though ascorbic acid and vitamin A contents were less under open condition, upon exposure to higher concentrations of CO2, there was tremendous increase in these quality parameters along with oxalate content. Both the varieties of cowpea recorded significant variations in growth, physiological and biochemical parameters when exposed to higher concentrations of CO2. But Anaswara recorded higher values for number of leaves (74.25), specific leaf area (454.53), root weight (15.04g), shoot weight (63.15g), total dry matter (78.76g), starch content (9.16mg g-1) reducing sugar (15.36mg g-1), GA (0.615 µg g-1) nitrate reductase (0.54 µ g g-1). Velllayani Jyothika recorded higher values for stomatal distribution (2893.8cm -1) and physiological and biochemical parameters like pigment composition (0.52 mg g-1)and total soluble protein (1.44 mg g-1). Flowering time was modified to a greater extent in Anaswara-2 days to first flowering and days to 50% flowering and so Anaswara was selected for molecular analyses. CO2 enrichment was found to influence the quality parameters in amaranthus. CO-1 showed a tremendous increase in ascorbic acid and vitamin A, but there was an increase in oxalate content also. During the period of study, environmental factors like temperature, humidity and sun shine hours were measured. There was an increase of 70C an average during the period and also an increase in leaf temperature. For gene expression studies flowering locust (FT) was selected. The DNA of Flowering locus T was amplified from Anaswara and CO-1. Differential expression was observed in both the crops under elevated CO2 condition. In the present study, both cowpea and amaranthus were found to be responding to elevated CO2 in terms of flowering time. This can be correlated with the higher photosynthate accumulation with a net positive effect on growth parameters. The increased gibberellic acid level displayed by both the crops upon CO2 enrichment can also play a role in signaling the crosstalk between reproduction and other developmental processes. Understanding the mechanisms involved in the regulatory network modulating floral initiation in response to elevated CO2 and elevated temperature will facilitate understanding and identifying options to develop plants better adapted to changing climate.ThesisItem Open Access Physiological and biochemical studies on growth, development and yield of ginger (Zingiber officinale rosc.)as influlenced by bioinoculants and phosphorus fertilization(Department of Plant Physiology, College of Agriculture, Vellayani, 2018) Amritha Lekshmi, M G; KAU; Viji, M MThe experiment entitled " Physiological and biochemical studies on growth,development and yield of ginger (Zingiber officinale Rosc.) as influenced by bionoculants and phosphorus fertilization," was undertaken at Department of Plant Physiology, College of Agriculture, Vellayani during 2016-18. The objective of the study was to elicit information on the physiological, biochemical attributes on plant growth, development and yield of ginger as influenced by bioinoculants such as mycorrhiza and Trichoderma viride combined with phosphorus fertilization. In this study ginger cultivar maran was grown in pots under completely randomized block design (CRD). Different levels of ‘P’ were applied to soil in pots viz. low (P2O5 -50% POP), medium (P2O5 as per POP) and high (P2O5 double dose of POP). The pots were inoculated with AMF or Trichoderma or both together in combination as per the treatments during the time of planting. Control plants were also maintained. The treatments were T1- control(P2O5 as per POP ),T2(P2O5 as per POP +AMF),T3 (P2O5 as per POP +Trichoderma), T4( P2O5 as per POP +AMF+ Trichoderma),T5 (P2O5-50% of POP),T6 ( P2O5-50% of POP +AMF),T7( P2O5-50% of POP +Trichoderma),T8 (P2O5-50% of POP +AMF+ Trichoderma ), T9 (P2O5-Double dose of POP), T10 (P2O5-Double dose of POP +AMF),T11 (P2O5-Double dose of POP +Trichoderma) and T12(P2O5-Double dose of +AMF+ Trichoderma). Effect of microbial inoculation and phosphorous fertilization on growth parameters such as shoot height, number of leaves , number of tillers and fresh ginger yield were observed at fourth ,sixth and eighth month. T6 recorded highest plant height up to sixth month but at eighth month, T8 recorded 42% increase in shoot height over control. T8 recorded maximum number of leaves and was found on par with T4 and T6. At maturity stage 64.2 % increases in number of tillers were observed in both treatments T4 and T6 than control. At final stage maximum fresh weight of ginger was recorded in T8 .At fourth month highest rhizome fresh weight was recorded in treatment T8 and was on par with T4. At sixth month maximum rhizome fresh weight was noticed for the treatment T8 and was on par with T6 .Plants which did not receive any microbial inoculation showed less values for all the above parameters at all stages. Physiological parameters such as photosynthetic rate, transpiration rate, stomatal conductance and leaf temperature did not show any significant difference at maturity stage. Treatment T8 recorded maximum value at fourth and sixth month for these parameters. A significant difference was observed among the treatments for chlorophyll and carotenoid content. Total chlorophyll content showed an increase in trend but at maturity chlorophyll content decreased in all treatments due to senescence. Throughout the growth stages, T8 recorded significantly higher value for chlorophyll a and total chlorophyll content. Chlorophyll stability index and cell membrane stability index of the plants under different treatments were found to be significantly different and treatment T8 recorded maximum value in all stage of analysis. Uptake of major nutrients such as N, P, K, Ca and Mg increased with microbial inoculation. Treatment T8 with combined inoculation of AMF and trichoderma and half dose of ‘P’ showed 49.2%, 58.4%, 120.6% and 20% increase in total protein, total sugar, phenol and reducing sugar content respectively at maturity stage. Significant difference existed for AMF colonisation percentage and AMF spore count between the treatments. Treatment T8 recorded maximum value for both the parameters along with T4 and T6.At sixth month AMF colonisation reached 100% for treatment T8. A decrease in trend was observed at final stage due to wilting of roots. Effect of microbial inoculants on yield parameters such as fresh weight, dry weight, rhizome thickness, rhizome spread and harvest index were studied. Treatment T8 recorded 35.5% and 39.2% increase in fresh and dry ginger yield over control. Highest rhizome spread was observed in treatment T8 and was found on par with T4 and T12 and the lowest value was obtained in control and T5. Rhizome thickness was recorded maximum in the treatment T8 and was found on par with T3, T4, T6 and T10. At maturity stage there was significant difference among the treatments for the harvest index. Volatile oil content at maturity stage ranged between 1.5% to 3% for different treatments. Treatment T8 recorded 65.7% increase in volatile oil content over control. Treatment T8 recorded highest oleoresin content (65.8%) and was on par with T6. Starch content also recorded highest value for treatment with half dose of phosphorus and combined application of microbes. This treatment recorded 28.8 % increase in starch content than control. Decrease in crude fibre content increase the quality of ginger. Microbial inoculation resulted in reduction of crude fibre content in ginger rhizomes. Maximum fibre content was recorded for the treatment T9 followed by control. Least value was recorded for treatment T8. Gingerol content was estimated by HPLC analysis. Gingerol is an important phytochemical which impart medicinal property to ginger. Microbial inoculation significantly changed gingerol content .Treatment T4 (0.96%) followed by T8 (0.85%) recorded highest value. Arbuscular mycorrhizal and trichoderma inoculation along with phosphorous fertilization has significantly improved growth ,yield and quality of ginger not only through increasing nutrient uptake, but also viz. stimulating photosynthetic parameters and biochemical properties of the ginger particularly under low phosphorous fertilization. Number of tillers, number of leaves and yield was recorded maximum for the treatments with microbial application. This was mainly due to increase in uptake of nutrients, especially in rhizome of ginger. Microbial inoculation increased total protein content, reducing sugar, total sugar content in ginger. However, these benefits in response to the microbial inoculation generally decreased when there was an increase in P fertilizer added to the soil, suggesting that phosphorous reduced AMF colonization and the corresponding effects. Microbial inoculation resulted in enhanced production of phenolic compounds such as gingerol (65.4 % increase over control) in rhizomes. Therefore the best treatment identified is half dose of phosphorous and combined inoculation of AMF and trichoderma. Hence it is concluded that microbial inoculation could replace fertilization application, especially the recommended dose of ‘P’ fertilization up to 50 %. It enhanced growth, development and yield of ginger. It is a feasible technique for the production of ginger plants with increased quantities of oleoresin and volatile oil and also to improve the medicinal value of ginger by increasing gingerol content.ThesisItem Open Access Physiology and management of submerged weeds in wetland rice ecosystem(Department of Plant Physiology,College of Horticulture, Vellanikkara, 2018) Athira, K A; KAU; Girija, TThe present investigation entitled “Physiology and management of submerged weeds in the wetland rice ecosystem” aimed to identify and characterize the different submerged weed species of wetland rice ecosystem, understand their growth pattern and evolve possible management practices. The study consisted of survey, identification and morphological characterization of submerged weeds of rice ecosystem of the central zone of Kerala. The effect of environmental conditions on growth and multiplication of the most common weed, Utricularia aurea and its control were also studied. Weed survey was conducted in ten locations each in Thrissur, Palakkad and Ernakulam districts of Kerala. Submerged weeds from the rice fields were collected along with soil and water samples from ten locations for further studies. The major submerged weeds in the rice ecosystem included hydrophytes and algal species. Seven hydrophytes and three species of algae were commonly seen in the region. The major hydrophytes were Utricularia aurea, Utricularia exoleta, Elodea canadensis, Hydrilla sp., Egeria densa, Cabomba sp. and Najas sp. while the common algal species were Spirogyra, Chara and Nitella. The water and soil samples collected were analyzed in the laboratory for different physico-chemical properties such as pH, electrical conductivity (EC), total suspended solids (TSS), dissolved oxygen (DO), E. coli content, soil enzymes and hormones which affect growth of the rice plant. pH had the larger influence on growth of submerged weed species. Highest weed growth was observed between pH range of. 7.2 to 8.01 (neutral to alkaline). The presence of submerged weeds reduced the dissolved oxygen content of water and increased the content of TSS and E. coli, adversely affecting water quality and supply of oxygen to rice root. The presence of dissolved nitrate in the water may be a major reason for high incidence of these weeds. Soil enzymes and hormones also positively influenced their growth. The physiological parameters such as chlorophyll content, nitrate reductase activity, indole acetic acid (IAA) and GA contents of the weeds were also studied. It was found that IAA, GA and chlorophyll promoted weed growth. High nitrate reductase was observed in Nitella. Elodea canadensis had the capacity to purify the water by reducing the TSS and improving the dissolved oxygen content. The most common submerged weed in the rice ecosystem was Utricularia aurea and hence this weed was selected to study the effect of light, UV radiation and chemicals on growth and multiplication. Effect of light on weed growth was studied by using different shade nets which allowed 50 per cent and 75 per cent light infiltration. Effect of UV radiation was studied by growing the plants under polyhouse cladded with mylar film which allowed zero UV and polyethylene sheet which allowed 80 per cent UV radiation. Growth and multiplication of Utricularia aurea in the open condition and different light and UV levels were compared. Zero UV and temperature in the range of 30-310C was found to be ideal for weed growth. Both high water temperature and high UV were detrimental. Growth of the weed was not altered with shading, indicating that moderate shade not affect the weed growth. Effect of CuSO4 (1ppm, 2ppm and 3ppm), 2, 4-D (1ppm, 2ppm and 3ppm) and lime (100 ppm, 200 ppm and 300 ppm) on growth of Utricularia aurea was measured by recording the rate of degradation of the weed one month after application in pot culture study. Good control was obtained with higher concentrations of all the three chemicals tried. Three ppm of CuSO4, 2, 4-D and 300 ppm lime gave better results. Lime was found to be more effective in the control of Utricularia aurea.
