PG Thesis

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    Evaluation of bacillus thuringiensis berliner for the management of rice leaf folders
    (Department of Agricultural Entomology, College of Horticulture,Vellanikara, 1998) Asha, R; Babu Philip, M
    The study was conducted with the objective of survey and identification of the natural enemies of leaffolder and other lepidopterous pests of rice and to evaluate the efficacy of B. t. formulations against the leaffolders of rice. The survey was conducted at the Agricultural Research Station, Mannuthy and the Kerala State Agricultural Department Seed Farm, Mannuthy. The field trials to evaluate the efficacy of rice leaffolders were conducted at the Agricultural Research Station, Mannuthy during Kharif 1995 and Kharif 1996 . .. The present study revealed the occurrence of five viroses, two bacterioses and a nematode infection in the various lepidopterous pests of rice. Four Braconids, three Ichneumonids one Eulophid, one Chalcid and a Bethylid parasite were also recorded from various lepidopterous pests of rice. The B.t. formulations tested were found to be effective against the leaf folders on rice. The percentage of leaf damage during Kharif 1995 showed the B.t. formulations Biotox, BTT, Biolep to be the best treatments. With respect ~to the grain yield, BTT was the best treatment followed by Dipel, Biolep and Biotox. During Kharif 1996, Dipel followed by Biotox and monocrotophos were found to be the best in terms of percentage of leaf damage. Based on the yield during 1996, BTT was found to be the superior one followed by monocrotophos. B. t formulations were found to be safe to predatory spiders, other predators and paras i toids of folders. the leaf The combination of BTT and C.m. GV was able t.o reduce the leaf damage and data on larval mortality showed the leaf folder larvae to be susceptible to the combination of BTT and C.m. GV. The GV of C. medinalis was found to be highly host specific.
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    Response of selected forestry and agroforestry tree seedling to water stress
    (Department of Tree Physiology and Breeding, College of Forestry, Vellanikkara, Thrissur, 1996) Rajesh, N; Ashokan, P K
    An experiment was conducted at the College of Forestry, Kerala Agricultural University, Vellanikkara, Thrissur during the period from 1994 to 1995 with seedlings of Acacia mangium Willd., Ailanthus triphysa (Dennst.) Alston., Pterocarpus marsupium Roxb., Swietenia macrophylla King and Tectona grandis L.F. to study the response of the species to water stress. The results showed that the growth characteristics and Physiological behaviour of all the five species were adversely affected due to water stress. Among the five species studied S. macrophylla was the most sensitive species and did not show much adaptations to tolerate water stress. Eventhough A. mangium showed adaptations like quick closure of stomata, thick cuticle and low chloroplast disintegration when exposed to water stress, growth characteristics were found to be adversely affected due to water stress. So the species has to be tested for its water stress tolerance in a long term experiment. Pterocarpus marsupium was also found to be sensitive to water stress and all the growth characters were adversely affected. However, it showed relatively high net photosynthesis and relative growth rate. Ailanthus triphysa was the least sensitive species to water stress. Considering the relative growth rate and net photosynthesis, A. triphysa and P. marsupium are rated to perform well under dry situations. Among the five species studied T. grandis seedlings showed symptoms of permanent wilting when the water stress was increased from moderate (~ 5 Bar SMT) to severe (~ 10 Bar SMT) levels. Other species did not show permanent wilting even when the plants were not watered for nine days condinuously (S3). Growth characteristics in T. grandis was not much affected due to mild (S1) levels of water stress eventhough the plants wilted and dried under severe water stress (S3).
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    Shade tolerance of guinea grass var. Mackuenii under different levels of potassium
    (Department of Agronomy, College of Agriculture, Vellayani, 1982) Mullakoya, P; Raghavan Pillai, G
    An investigation was carried out in the Instructional Farm attached to the College of Agriculture, Vellayani, during 1981-82 with the objective to assess the production potential of guinea grass var. Mackuenii under varying intensities of shade. It was also aimed to assess the potassium requirement was laid out in a 4 x 4 factorial randomised block design with 3 replications. The results of the study are summarised below: (1) Height of grass was positively influenced by both shade intensities and potash levels. (2) Leaf area of grass was increased with increase in shade intensities and potash levels. (3) Tiller production was adversely affected by shade, while potash application increased tiller number of grasses.
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    Calcium, magnesium and boron nutrition for grow bag cultivation of cabbage (brassica oleracea L. var. capitata)
    (Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2018) Parvathy, P J; Gladis, R
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    Carbon sequestration and crop weather relations in long term fertilizer experiments
    (Academy of Climete Change Education and Research, Vellanikkara, 2018) Sudhamani, P; Thulasi, V
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    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; Manju, R V
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    Modeling rice production in kole lands and its vulnerability to climate change
    (Academy of Climate Change Education and Research Vellanikkara, 2018) Surabhi, S R; Sandeep, S
    Rice is the most important staple food crop for more than 2/3rd of India’s population, and is the primary source of food for more than three billion people globally. Hence rice production plays a significant role in food security under a changing climate. The Kole lands is a multiple use wetland ecosystem covering an area of 13,632 ha spread over Thrissur and Malappuram districts, and form one of the rice granaries of Kerala. It is a part of the unique Vembanad-Kole wetland ecosystem. The objectives of the study were to develop crop weather relationship for the predominant rice varieties and assess possible changes in yield due to climate change and to study the impact of abiotic factors and farming practices on rice production using simulation model. Daily weather data for the period 1998-2016 were collected from the India Meteorological Department, Thiruvananthapuram. Information on area, production and productivity of rice in Kole lands was collected from Agriculture Statistics Report - Department of Economics and Statistics, Kerala. The weather data from General Circulation Models based on RCP 4.5 and 8.5 were used for the analysis and projections were made up to 2050. Weather cock v.1.5 was used for converting the daily weather data into standard week, month and seasonal formats. The rainfall parameters or indices like seasonal and monthly rainfall, rainy days and high rainfall events were calculated. It is also used to compute PET and Thornthwaite water balances. The crop simulation model DSSAT –developed by IBSNAT was used for studying the impact of climate change on these ecosystems. The monthly rainfall of Kole lands indicates that there was an increase in rainfall during the months of June, July and August as per RCP 4.5 and 8.5. According to RCP 4.5 and 8.5 an increasing trend in number of seasonal rainy days was observed during the monsoon seasons. The maximum amount of potential evapotranspiration was observed during the month of May, whereas the minimum in, November December, and January. The months of January, February, March, April, November and December were found to have no surplus. Whereas water deficit is projected to happen during the month of march. The maximum amount of surplus was found to occur in July and the yearly value shows an increase from the current condition. The area under rice production has shown a declining in Kole lands over a period of 2008 – 2017. Results indicates that the productivity of rice in Kole lands during the first cropping season was 2.08 t/ha. By 2030, the second cropping season was projected to have a yield of 3.124 t/ha. By 2050, the third cropping season would surpass the productivity of first two seasons with productivity of 3.424 t/ha.
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    Assessment of rice (oryza sativa L.) production under climate change scenarios
    (Department of Agricultural Meteorology Vellanikkara, 2017) Jasti Venkata Satish; Ajithkumar, B
    Agriculture is sensitive to short term changes in weather and to seasonal, annual and long term variations in climate. Climate change will have decisive impact on crop production and the prediction of this climate change emerged as a major research priority during the past decade. Numerous estimates for the impending decade projects that continuous rise of anthropogenic forcing leads to increase in greenhouse gas (GHG) atmospheric concentrations, is expected to alter regional temperature and precipitation patterns, also contributing to higher risk of extreme weather events and climate irregularity (IPCC, 2013), with obvious implications on crops (Porter and Semenov, 2005). Rice (Oryza sativa L.) is vulnerable to unfavourable weather events and climate conditions. Despite technological advances such as improved crop varieties and irrigation systems, weather and climate play significant roles in rice production. The present investigation “Assessment of rice (Oryza sativa L.) production under climate change scenarios” was carried out in the Department of Agricultural Meteorology, College of Horticulture, Vellanikkara during 2016-17, to determine the crop weather relationship, to validate the CERES (Crop Environment Resource Synthesis) -Rice model for the varieties Jyothi and Kanchana and to project the changes of rice yield and growth under climate change scenarios. The field experiment was conducted at Agricultural Research Station, Mannuthy during the kharif season of 2016. Split plot design was adopted with five dates of planting viz., 5th June, 20th June, 5th July, 20th July and 5th August as the main plot treatments and two varieties viz., Jyothi and Kanchana as the sub plot treatments. The number of replications for the experiment was four. Analysis of weather with crop duration and yield showed that maximum and minimum temperatures showed increasing trend towards late plantings, whereas the relative humidity, rainfall and rainy days were found to be low in late planting than during early plantings. To determine the critical weather elements affecting the crop duration, correlation analysis was performed. Number of days for panicle initiation to booting stage, decreased with increase in maximum and minimum temperature, whereas, the reverse was observed with afternoon relative humidity, afternoon vapour pressure deficit and rainfall in Jyothi. In case of Kanchana, days for transplanting to active tillering decreased with increase in maximum, minimum temperatures and bright sunshine hours, whereas relative humidity, afternoon vapour pressure deficit, rainfall and 159 number of rainy days showed a positive influence. The mean yield of Jyothi and Kanchana on June 5th planting found to be on par with June 20th planting. The correlation analysis showed that with increase in maximum and minimum temperature during transplanting to Active tillering will reduce the yield for both Jyothi and Kanchana The crop genetic coefficients that influence the occurrence of developmental stages in the CERES-Rice models were validated, to achieve the best possible agreement between the simulated and observed values. Predicted yield and phenology of both rice varieties, Jyothi and Kanchana under different planting dates were reasonably close to the observed values. Analysis of yield and growth phases of rice under different climate change scenarios ( Representative Concentration Pathways (RCP) 4.5 and 8.5) for the time periods 2050s and 2080s showed that, days taken to panicle initiation, anthesis and physiological maturity decreases for all the five different dates of planting. This may be due to increase in maximum and minimum temperatures during the future scenarios. The predicted values of rice yield for the climate change scenarios during first and second plantings for the time periods 2050s and 2080s showed a low yield whereas increase in yield was observed in third, fourth and fifth plantings compared with 2016. This increase in yield is may be due to combined effect of increase in CO2 (538 and 936ppm) and solar radiation during the panicle initiation, anthesis and physiological maturity for the delayed plantings. These findings suggests that, planting date need to be shifted to late July and early August in case of kharif crop in the central zone of Kerala in future.
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    Rhizosphere management for higher root production in ashwagandha (Withania somnifera L. Dunal)
    (Deparment of Agronomy, College of Agriculture, Padannakkad, 2017) Ashiba, A; Anilkumar, A S
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    Photosynthesis and enzyme activities regulating starch biosynthesis in different varieties of sweet potato (Ipomoea batatas Lam.)
    (Department of Plant Biotechnology, College of Agriculture, Vellayani, 2016) Aswini Krishnan, N K; Ravi, V
    The present study entitled “Photosynthesis and Enzyme activities regulating starch biosynthesis in different varieties of Sweet potato (Ipomoeabatatas Lam.)” was conducted at ICAR-CTCRI, Trivandrum during the period 2015-2016. The objective of the work was to the study the relation between photosynthesis, leaf area and enzyme activities involved in regulating starch biosynthesis in different genotypes of sweet potato and to identify the limiting factor(s) in low starch varieties of Sweet potato. The rate of photosynthesis, morphological and biochemical parameters and enzymes activities involved in the starch biosynthesis were recorded at monthly intervals in selected varieties. Morphological parameters such as total number of leaves per plant, leaf area and tuber yield per plant were recorded during 1 to 4 MAP. Rate of photosynthesis was measured using IRGA (infra-red gas analyzer). The leaf area and photosynthetic rate were directly increasing the productivity which was found to be higher in the Sree Arun and Kanhangad variety. Biochemical parameters such as sucrose and starch content were estimated in leaves and tubers of sweet potato varieties. The sucrose content was relatively higher in leaves of Kanhangad variety and in tubers of ST-13 variety. Starch content was higher in the variety Sree Arun which had a direct relation with the photosynthetic rate and tuber yield. Activities of enzymes such as AGPase, starch synthase (SS), sucrose phosphate synthase (SPS), sucrose synthase (SuSy) and invertase were measured in both the leaves and tubers of sweet potato. AGPase and SS were directly involved in the tuberization throughout the development which was observed in Sree Arun variety. SPS was highly active in leaves than tubers. SuSy and invertase are mainly involved in the sucrose metabolism in leaves and highly active during the day time. The increased activity of AGPase and SS in sweet potato tubers will open a new strategy for bioengineering the efficiency of enzymes to improve the starch content in low yielding sweet potato varieties. A detailed molecular study on enzymes involved in starch biosynthesis will be necessary for increasing or improving the starch content in tuber crops.