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ThesisItem Open Access Evaluvation of China aster [Callistephus chinensis (L.) Nees.] for cultivation in tropical plains(Department of Floriculture and Landscaping, College of Horticulture, Vellanikkara, 2019) Alfin, Santhosh; KAU; Anupama, T VChina aster [Callistephus chinenesis (L.) Nees.] is one of the most important annual flower crops grown in India for cut flower as well as loose flower purposes. It ranks third next to chrysanthemum and marigold among the annual flowers and has gained popularity due to ease of cultivation, diversity of colours and good vase life. It is also used for bedding purpose in landscapes and as pot plants. In Kerala, the demand for annual flower crops is on the rise, however the cultivation is limited. China aster due to its hardy nature can be grown as a pure crop as well as intercrop in coconut gardens. The investigation entitled ‘Evaluation of China aster [Callistephus chinenesis (L.) Nees.] for cultivation in tropical plains’ was conducted at the Department of Floriculture and Landscaping during 2018-2019 with an objective to evaluate the performance of China aster for cultivation in tropical plains. Ten varieties of China aster viz. Arka Kamini, Arka Shashank, Arka Archana, Phule Ganesh White, Phule Ganesh Violet, Phule Ganesh Pink, Phule Ganesh Purple, AAC-1, Local Pink and Mat White were evaluated for vegetative, floral and post harvest characters. The varieties showed significant variation for vegetative characters. In all the varieties, leaf dentation was present and leaf shape was ovate for all varieties except Arka Shashank which had linear leaf shape. Stem colouration and leaf mid rib colouration were absent in varieties such as Arka Shashank, Arka Archana, Phule Ganesh White and Mat White and the rest of the six varieties showed the presence of purplish stem and mid rib colouration. The variety Phule Ganesh Pink was superior in plant height (68.86 cm) at 3 months after planting. The characters like plant spread (50.08 cm), number of leaves (56.48), number of primary branches (14.25) and stem girth (11.09 cm) were also highest in variety Phule Ganesh Pink. Leaf area was the highest in variety Phule Ganesh White (34.31 cm2). The variety Mat White was significantly inferior for all the vegetative characters observed. Floral characters showed significant variation among the varieties. Powderpuff flower type was observed in Arka Shashank and all the other varieties had semi-double type flower. Days to bud initiation was minimum in variety Arka Shashank (44.40 days) and maximum in Phule Ganesh White (73.67 days). The same trend was observed for days to complete flower opening and days to 50 per cent flowering. The variety Local Pink had the highest duration of flowering (62.40 days) and variety Mat White (45.20 days) had the lowest duration of flowering. The variety Arka Shashank produced highest number of flowers per plant (20.20). The flower stalk length (21.13 cm), flower weight (6.94 g) and flower diameter (7.07 cm) were the highest in the variety Phule Ganesh Pink. The variety Phule Ganesh White was superior in terms of number of disc florets per head (251.00) whereas Phule Ganesh Pink had the highest number of ray florets per head (201.20). The flower yield per plant was highest in variety Phule Ganesh Pink (55.99 g). The variety Phule Ganesh White recorded the highest seed yield per flower (1.27 g) and seed germination (65.27 %). Longest shelf life was observed in variety Phule Ganesh Pink (3.67 days) which was on par with Phule Ganesh White (3.33 days) and physiological loss of weight was recorded highest in Phule Ganesh White (35.70 %). The variety Phule Ganesh Pink had the longest vase life (13.93 days) and total water uptake was also maximum in variety Phule Ganesh Pink (20.27 ml). Anthocyanin content of flowers was recorded highest in the variety Phule Ganesh Violet (51.87 mg/g) followed by Arka Kamini (48.62 mg/g). Dendrogram based on D2 statistics considering qualitative and quantitative characters indicated that high amount of variability is present among the varieties. Correlation and path analysis revealed that the characters such as number of primary branches (0.978), plant spread (0.894), leaf area (0.796) and flower weight (0.933) were having significant positive correlation with flower yield per plant with a direct effect of 0.150, 0.199, 0.281 and 0.498 respectively. Ranking of varieties was done individually for loose flower and cut flower types. In ranking for loose flower types, variety Phule Ganesh Pink scored first position which was followed by Phule Ganesh White and Local Pink. When varieties were ranked for cut flower types, first position was scored by Phule Ganesh Pink while second position was shared by Phule Ganesh White, Phule Ganesh Purple and Local Pink. In overall ranking the variety Phule Ganesh Pink occupied first position followed by Phule Ganesh White and Local Pink and these can be recommended for commercial cultivation in tropical plains of Kerala during winter season.ThesisItem Open Access Standardization of growing media and growth regulators for rose (Rosa ssp.) under top ventilated rain shelter(Department of Floriculture and Landscaping, College of Horticulture, Vellanikkara, 2019) Sijo, John; KAU; Mini, SankarRose is acclaimed as ‘Queen of flowers’ because of its colour, fragrance and elegance. Cut roses are having very high demand in domestic as well as international market due to versatile uses. Roses can be successfully cultivated under top ventilated rain shelters in Kerala. Soilless media consist of vermiculite, perlite, and rockwool are popularly used for commercial production of rose under protected condition. These are costly and not easily available to farmers. Thus, there is a need to develop a cost effective growing media with locally available materials. Exogenous application of plant growth regulators improves the yield and quality of cut flowers by manipulating hormonal regulations in the plant system. Even though commercial formulations of different growth regulators are available in the market, the type and precise concentration of growth regulators are to be standardised. Hence the present study entitled “Standardization of growing media and growth regulators for rose (Rosa spp.) under top ventilated rain shelter” was carried out in the Department of Floriculture and Landscaping, College of Horticulture, Vellanikkara during 2018-2019. Objective of the study was to standardize growing media and growth regulators for commercial production of cut roses in agroclimatic conditions of Kerala. The experiment consisted of twelve treatments, which included different combinations of three growing media viz; soil + M-sand + cocopeat + FYM (M1), soil + M-sand + cocopeat + vermicompost (M2) and soil + M-sand + cocopeat + poultry manure (M3) in 2:1:1:1 ratio and two levels each of two growth regulators viz; Benzyl adenine (BA) and Gibberellic acid (GA) at 200 and 250 ppm. Six months old grafts of rose variety ‘Tajmahal’ was used for the study. Observations on growth characters, yield, post harvest aspects as well as nutrient status of the growing media were recorded. With regard to vegetative characters, growing media, growth regulators and interaction between growing media and growth regulators had significant influence during the period of observation. Growing media containing FYM (M1) recorded the greatest plant height and was on par with growing media containing vermicompost (M2). Among growth regulators, GA 250 ppm was found to be superior in terms of plant height. With respect to interaction effect, greatest plant height was observed under the media containing FYM (M1) and GA at 250 ppm. Plant spread was highest under medium containing FYM (M1). Growth regulators had significant influence on plant spread and BA at 200 and 250 ppm were superior and on par in terms of this parameter. Regarding interaction, growing media containing FYM (M1) along with 200 ppm BA was observed to have the highest plant spread during the growth period. Media containing FYM (M1) as well as vermicompost (M2) were found to produce more number of branches and among growth regulators, BA at 200 and 250 ppm were on par and superior with respect to this parameter. Regarding interaction effect, highest number of branches was observed under growing media containing FYM (M1) and BA at 200 ppm. Significant effects of growing media could be observed on floral characters and media containing FYM (M1) was found to be superior with respect to floral characters viz; length of flower bud (3.37 cm), diameter of flower bud (2.16 cm), number of flowers /plant (5.04), number of petals/ flower (51.92), stalk length (47.94 cm) and flower diameter at fully opened stage (8.44 cm). Growing media containing FYM (M1) and growing media containing vermicompost (M2) were on par in terms of other floral characters viz; length of flower shoot, neck girth and stalk girth of flower. With respect to the influence of growth regulators on floral characters, a greater number of flowers/plant (5.38 and 5.10) as well as largest flowers at fully opened stage (8.33 and 7.99 cm) were observed under BA at 200 and 250 ppm. Stalk length of the flower was found to be maximum under GA at 200 ppm (47.92 cm). Highest length of flower shoot was observed in GA at 200 ppm and BA at 200 ppm which were on par with each other (38.79 and 36.94 cm respectively). Growing media and growth regulator interaction had significant influence on floral parameters viz; stalk length and number of petals per flower. Media containing FYM (M1) with GA 200 as well as 250 ppm were found to have maximum stalk length (52.48 and 50.09 cm respectively). Highest number of petals were observed under media containing FYM (M1) along with BA 200 and 250 ppm, media containing FYM (M1) along with GA 200 and 250 ppm, media containing vermicompost (M2) along with BA 200 ppm and GA 200 ppm as well as media containing poultry manure (M3) along with BA 200 ppm. Early initiation of flower bud was observed under media containing FYM (M1) along with BA 250 ppm (119.22 days). Regarding post harvest characters, media containing FYM (M1) was superior in terms of fresh weight of flower (16.36 g), total water uptake (49.48 ml) and vase life (8.46 days). Among growth regulators BA 200 ppm had longest vase life which was on par with GA at 200 ppm. Maximum fresh weight was observed under BA 200 ppm (15.17g). With regard to interaction effect, treatment combination of FYM + BA at 200 was found to have maximum vase life and fresh weight of flower (9.38 days and 18.71g respectively). Considering overall performance, growing media combination of soil + M-sand + cocopeat + FYM (2:1:1:1) along with monthly application of BA at 200 ppm can be recommended for commercial cultivation of rose under protected condition in Kerala.ThesisItem Open Access Carbon sequestration potential of selected seaweeds of Thikkodi, Kerala(Academy of Climate Change Education and Research, Vellanikkara, 2019) Saranya, M S; KAU; Vinod, KThe coastal blue carbon is the carbon sequestered by mangrove, tidal marshes, seagrasses and macroalgae which account for less than 0.5% of the seabed. Unlike, other blue carbon sectors (mangroves, tidal marshes and seagrasses), the macroalgae do not have sedimentary substratum. The macroalgae are commonly known as seaweeds. The ‘seaweeds’ as the name suggest is not an unwanted plant or weed. It has an important role in the marine ecosystem by acting as a sink for carbon emissions. The present study is based on the carbon sequestration potential of selected seaweeds of Thikkodi coast, Kerala. The state of Kerala has a long coastline of about 580 km, ranking only third among all the maritime states of the country. Some of these coastline stretches are pegged with areas of seaweed resources. The Thikkodi coast (11º28’30.8” N, 75º37’04.5”E) in the Kozhikode district of Kerala is well known for its rocky intertidal coast with a luxuriant growth of seaweeds of diverse species. An extensive study of seaweeds and their species diversity was carried out for a period of one year from September 2018 to August 2019 along the Thikkodi coast of Kerala. A total of 40 species of seaweeds were recorded which belonged to 23 genera, 18 families and 14 orders. A total of 19 species belonged to Chlorophyta, while 12 species belonged to Rhodophyta and 9 species belonged to Phaeophyta. The distribution and seasonal abundance of different species along the Thikkodi coast was also studied. The biodiversity indices were studied using PRIMER (Plymouth Routines in Multivariate Ecological Research). The biodiversity indices such as Shannon-Wiener diversity (H’), Pielou’s evenness (J’), Margalef species richness (d) were calculated. The seaweeds collected from Thikkodi coast were used to carry out the carbon sequestration potential studies. While comparing the three zones, the highest value of species richness (S) was obtained in zone 1 (S=14.00), followed by zone 2 (S=8.75) and zone 3 (S=7.08). The Margalef’s index (d) which incorporates the number of individuals (N) and species (S) was the highest in zone 1 (2.10), while it was minimum in zone 3 (1.08). The equitability or individuals among the different species showed much variation between the zones and the values ranged from 0.67 (zone 2) to 0.77 (zone 1). In the present study, the Shannon Wiener Index (H’) showed wide variation between the zones ranging from the lowest value of 1.33 (zone 3) to the highest value of 1.99 (zone 1). The Simpson Index (1-Lambda’) showed variations in values ranging from 0.66 (zone 3) to 0.82 (zone 1). The experiments were conducted on selected seaweeds particularly Gracilaria corticata, Caulerpa scalpelliformis and Caulerpa peltata. Carbon dioxide was dissolved in seawater at different concentrations using a soda maker by adjusting the fizz. After determining the initial CO2, the seaweeds were incubated in 125ml light bottles under a water column of 50-60cm for 2 hours. The initial CO2 concentration (mg/l) and the CO2 utilization were examined by titrating the seawater against 0.5N Sodium hydroxide solution using Phenolphthalein indicator. The Gross Primary Production (GPP) and Net Primary Production (NPP) were also estimated. For Gracilaria corticata, the utilization efficiency increased from 33.33% to 83.33% in lower CO2 concentration of 26.4mg/l and 79.2mg/l respectively. For Caulerpa scalpelliformis, the utilization efficiency increased from 25% to 42.86% in a lower CO2 concentration of 17.6mg/l and 30.8mg/l respectively. For Caulerpa peltata, the utilization efficiency increased from 66.67% to 75% in a lower CO2 concentration of 13.2mg/l and 35.2 mg/l respectively. When the concentration of CO2was increased beyond a threshold level, the CO2 utilization efficiency decreases and cease down to zero .Same is the case for productivity. Therefore the study implies that the carbon sequestration potential of different species of seaweeds varies. The macroalgae have a greater potential to act as carbon sink and based on the sequestration potential of seaweeds, selection of different species of seaweeds can be made possible for developing Seaweed Aquaculture Beds (SABs). The SABs provide important structure in coastal ecosystem and play an incredible role in climate change mitigation aspects.ThesisItem Open Access In vitro studies on anti-infective properties of leaf and root extracts of selected medicinal plants against gastro intestinal bacterial pathogens.(Department of Plant Biotechnology, College of Agriculture, Vellayani, 2019) Anjana, Babu; KAU; Shiburaj, SugathanThe thesis entitled “in vitro studies on anti-infective properties of leaf and root extracts of selected medicinal plant against gastro intestinal bacterial pathogenes” was carried out in the Microbiology division of Jawaharlal Nehru Tropical Botanic Garden and Research Institute, Palode, during 2018-2019 academic years.The objective of the study was Screening of medicinal plant extracts for anti infective property against gastro intestinal bacterial pathogens and identification of lead compounds, targeted efficacy testing of selected compounds against FtsZ proteins through in vitro and in silico approaches, demonstrating the effect of the compounds identified on virulence factors and bio-film formation of enteropathogens. Diarrhoeal diseases remain a leading cause of preventable death, especially among children under five in developing countries. Acute watery diarrhoea mainly affecting children of developing countries that results in dramatic dehydration and it is most dangerous in the very young. Enterotoxigenic Escherichia coli or Vibrio cholerae are most common causative agent of acute watery diarrhoea. Diarrhoea also cause huge economic burden on people of impoverished countries. There is need for novel anti-infective agents that can prevent disease and economic burden of diarrhoea. Developing countries are rich source of traditional knowledge and natural resources. These resources can be channelized to develop novel anti-diarrhoeal agents that can prevent emergence and dissemination of gastrointestinal pathogen including drug-resistant strains. Many diarrhoeal diseases are known to be treated with herbal remedies throughout the history of humankind. Even today, plant materials continue to play a major role in primary health care as therapeutic remedies in many developing countries. For centuries, many secondary metabolites present in leaves are found to have an outstanding role in medical world. Most of these compounds belong to alkaloids, flavonoids, terpenoids, steroids, saponins, quinones, coumarin and tannins. Leafs and roots are been extensively used in folk and modern medicine for treating various diseases. 105 We have explored anti-infective activity of the leaf and roots ethanol extract of five medicinal plants Moringa oleifera, Bixa orellana, Persicaria glabra, Pimenta dioica and Homonia riparia against enteropathogens like E. coli, V. cholera, E. faecalis, S. Typhi and S. aureus. Among these extractes hot ethanol extracts of persicaria glabra exhibited antibacterial activity against gastrointestinal pathogens such as E. coli, V. cholera, E. faecalis, S. Typhi and S. aureus. It also induced filamentation of Bacillus subtilis 168 which is an indication of cell division inhibition. The active compound present in persicaria glabra extract was identified to be querecetin, this compound can be used to develop novel anti-diarrhoeal agents.ThesisItem Open Access Study the impact of abiotic stress on photosynthetic potential of tropical tuber crops under elevated CO2(Academy of Climate Change Education and Research, Vellanikkara, 2019) Ancy, P; KAU; Nameer, P OClimate change and agriculture are interconnected processes, both of which take place on a universal scale. Global warming is expected to have significant impacts on agriculture. Most of the studies reported a positive impact in photosynthetic rate of C3 plants due to eCO2. However other players of climate change such as drought and rising temperature can harmfully affect crops. Cassava and sweet potato are two major tropical root crops grown in India. The main objective of the present study was to figure out the impact of adverse conditions of climate change such as water deficit stress and high temperature stress on photosynthetic potential of tropical tuber crops under elevated CO2 and there by identify crop/varieties suitable for changing climate conditions. The study was conducted during the period of October 2018 to July 2019 on four contrasting cassava and four contrasting sweet potato varieties. Observations on photosynthetic parameters viz., the net photosynthetic rate (Pn), stomatal conductance (gs) transpiration and sub-stomatal/intercellular CO2 concentration (Ci) were recorded using a LI6400 portable photosynthesis system, LI-COR Inc, Lincoln, USA. Elevated CO2 have positive effects on photosynthetic parameters under WDS free as well as WDS conditions in cassava as well as sweet potato. Even though WDS reduces photosynthetic rate, eCO2 could sustain greater Pn rate than ambient CO2 under WDS. Under eCO2 rising temperature can benefit cassava and sweet potato only under WDS free conditions. For cassava Pn was not significantly affected by temperatures. For sweet potato Pn significantly increased with rise in temperature. It indicates that increasing temperature is not a limiting factor for cassava and sweet potato, but beneficial for them under WDS free conditions. Responses of cassava and sweet potato to WDS and rising temperature are also influenced by the variety. Cassava variety Sree Athulya responses well to eCO2 as well as to rising temperature under WDS free conditions. Cassava variety Sree Vijaya can perform well under WDS compared to other varieties. Sweet potato variety Sree Arun exhibits higher Pn under WDS free conditions. Bhu Krishna and Kanhangad had high Pn under WDS as well as at higher temperature. From this study it can be concluded that tropical root and tuber crops especially cassava and sweet potato have a great potential for better adaptation at elevated CO2 environment under adverse climate conditions such as water deficit stress and increasing temperature. They can become crops providing food security for future environment under climate change.ThesisItem Open Access Precision farming techniques for quality seed produciton in okra (abelmoschus esculentus (l.) moench)(Department of Seed Science and Technology, College of Horticulture, Vellanikkara, 2019) Rosna, S; KAU; Sreelatha, UQuality seeds of okra, a popular vegetable crop in Kerala, are in great demand. An experiment was conducted during the period from January to April 2019 at the Centre for High-tech Horticulture and Precision Farming, Vellanikkara, to study the effect of precision farming techniques on growth, fruit and seed yield of okra. The field experiment was laid out in a Randomized Block Design (RBD) with 7 treatments which included two levels of irrigation viz., I1- Drip irrigation at 75% evapo-transpiration (EP) and I2- Drip irrigation at 100% EP and three levels of Fertigation viz., F1: 75% RDF (recommended dose of fertilizer), F2:100% RDF and F3:125% RDF. Fertilizer doses as per POP recommendation for the crop i.e., 110:35:70 kg NPK/ ha was adjusted based on soil test data. Drip irrigation was given daily based on PAN evaporation data while fertigation was administered twice a week. All the drip fertigation plots were mulched with 30 μ silver polythene film. A plot that was administered flood irrigation along with soil application of fertilizer as per POP fixed, vide soil test data, served as the control. The growth parameters of the crop in all the drip fertigation treatments were significantly superior to control. I1F1 exhibited significant superiority over other treatments with respect to plant height (84.40 cm), height of the first bearing node (17.55 cm), LAI (1.19) and fruit set (73.00%). Early flowering (47.33days) was also observed in this treatment. Between the different levels of irrigation, I1 (irrigation at 75% EP) showed significant increase in plant height (79.23 cm), height of the first bearing node (14.40 cm), LAI (1.01) and fruit set (70.33%) when compared to I2 (100% EP). I1 also registered earlier flowering (48.89 days) when compared to I2 (53.33 days). However, LAI was not influenced by different levels of irrigation. No significant difference was exerted by different levels of fertigation on characters like plant height, LAI, days to 50% flowering and fruit set. However, in the case of first bearing node, F1 (15.21 cm) followed by F3 (13.90 cm) was superior to F2 (12.95 cm). Significant interaction effect of irrigation and fertigation levels was evident with respect to LAI and fruit set. Fruit characters like length, girth, weight, mature fruit yield per plant and number of mature fruits per plant were significantly superior in drip fertigation treatments compared to control. Except I2F3, all other fertigation treatment produced significantly thicker fruits than the control (1.90 cm). Mature fruit weight was significantly high in treatments 11F1 (9.10 g) and I1F2 (8.59 g), followed by I2F2 (7.60g). However, mature fruit yield (154.85 g) and number of mature fruits (30.91) were significantly high in I1F1. Fruit characters like fruit length and girth were not influenced by different levels of irrigation and fertigation as well as their interaction effect. However, I1 showed significant increase in fruit weight (8.09 g), mature fruit yield (116.49 g) and number of fruits (25.67g) when compared to I2. Mature fruit weight (8.20 g & 8.09 g) and number of fruits (24.19 & 22.98) were on par in F1 and F2. Among the interactions, I1F1 showed superior performance in fruit weight, mature fruit yield/plant and number of fruits/plant. With respect to seed characters like number of seeds per fruit, seed weight /fruit, seed yield per plant, 100 seed weight, seed germination and seedling vigour index, the drip fertigation treatments were significantly superior to control. Between the irrigation levels, I1 significantly increased number of seeds/fruit, seed yield/plant and seedling root length when compared to I2. But seedling vigour index was significantly higher in I2 (2504) compared to I1 (2424). However, characters like seed weight/fruit, 100 seed weight, 100 seed volume, germination, moisture content, hard seed content and seedling shoot length were not affected by irrigation levels. Among the fertigation levels, seed germination and seedling vigour index was highest in F1 (93.33 % and 2914) while F2 showed increased number of seeds/fruit (42.87) whereas F3 showed increased 100 seed weight (6.70g), seedling shoot length (22.68 cm) and low hard seed content (8.48%). Seed weight and seed yield were not influence by fertigation levels. Significant interaction effect of irrigation and fertigation levels were evident in number of seeds/fruit, 100 seed weight, seed germination and seedling root length. I1F1 was found to be significantly superior for most seed traits studied. But seedling vigour index was significantly higher in I2F1 (2947). Storage studies were conducted with seeds of okra variety, Arka Anamika procured from Centre for High-tech Horticulture and Precision Farming, Vellanikkara. The seeds were treated with polykote (synthetic polymer) @ 5 and 10 ml per kg of seed along with plant protection chemicals viz., carbendazim-mancozeb (Saaf- 2g/kg of seed) and bifenthrin (0.1%) or biocontrol agent- Trichoderma viridae (4g/kg of seed). Untreated seeds served as control. The seeds were packed in 700 gauge polyethylene bags and stored under both cold (refrigerated) and ambient conditions and seed quality parameters assessed at bimonthly intervals. With the advancement of storage period, germination declined irrespective of the treatments in both the storage conditions. Throughout the storage period, performance of treated seeds was found to be significantly superior over control. At the end of twelve months of storage, higher seed germination was recorded in seeds treated with polykote (10ml) + carbendazim- mancozeb (2g) + bifenthrin (0.1%) both under cold (75.33%) and ambient (71.33%) conditions. Lower values were recorded in untreated control (60.33 per cent under cold storage and 56.33 under ambient storage). Both seedling shoot length and root length were significantly higher in treatment with polykote (10ml) + carbendazim- mancozeb (2g) + bifenthrin (0.1%) both under cold and ambient conditions. Seedling dry weight was also significantly higher in the same treatment in the cold storage while in the ambient condition, there was no significant difference among the treatments. The EC of seed leachate and seed microflora also showed the same trend with very low value for polykote (10ml) +carbendazim- mancozeb (2g) + bifenthrin (0.1%) in both cold and ambient conditions. From the study it can be concluded that drip irrigation at 75% EP and 75% of RDF along with mulch, is best for seed production in okra. Storage of seeds treated with polykote (10ml) + carbendazim- mancozeb (2g) + bifenthrin (0.1%) in cold is recommended to ensure minimum seed certification standards.ThesisItem Open Access Alginate based consortial formulation of native microbial fertilizers(Department of Agricultural Microbiology, College of Horticulture, Vellanikkara, 2019) Alfiya Beegum, A; KAU; Surendra Gopal, KAt present, the available biofertilizers are bulky and have short shelf life due to contamination problem. Hence, a suitable formulation needs to be developed which is less bulky and has increased shelf life. Alginate is one of the most commonly used polymers for microbial encapsulation. It is commercially extracted from seaweeds like Macrocystis pyrifera, Ascophyllum nodosum, Laminaria etc. The present study was undertaken in the Department of Agricultural Microbiology, College of Horticulture, Vellanikkara to develop an alginate based formulation of nitrogen, phosphorus, and potash biofertilizers consortia and evaluate for growth enhancement using tomato as the test crop. Five isolates each of nitrogen fixers, phosphorus and potassium solubilizers from Wayanad district were obtained from the repository maintained in the Department of Agricultural Microbiology, COH, Vellanikkara. The bacterial isolates were screened for nitrogen fixation, phosphorus and potash solubilization along with indole acetic acid production. Amount of nitrogen fixed (22.63 mg of N g -1 sucrose utilized) and indole acetic acid production (6 μg ml-1) were highest for Microbacterium arborescence. Similarly, Burkholderia cepacia recorded the highest amount of phosphorus solubilization (64.83 μg ml-1) and indole acetic acid production (8.67 μg ml-1). Among the potassium solubilizers, Acinetobacter calcoaceticus solubilized the highest amount of potassium (41.63 μg ml-1) under in vitro conditions. Microbacterium arborescence, Microbacterium testaceum and Nguyenibacter vanlangensis were selected as the three most promising nitrogen fixers. Similarly, the phosphorus solubilizers selected were Burkholderia cepacia, Bacillus subtilis (KASB5) and Bacillus subtilis (H4). The potassium solubilizers selected were Acinetobacter calcoaceticus, Burkholderia sp. and Brevibacterium sp. Compatibility studies were conducted among the selected bacterial isolates using cross streak method which showed no inhibition at the intersection of two bacterial isolates. The compatible isolate was further confirmed by dual culture method. The efficient isolates selected for consortia preparation were Microbacterium arborescence + Burkholderia cepacia + Acinetobacter calcoaceticus (N1P1K1), Microbacterium arborescence + Bacillus subtilis (KASB5) + Acinetobacter calcoaceticus (N2P2K2) and Microbacterium testaceum + Burkholderia cepacia + Burkholderia sp. (N3P3K3). In order to prepare a sterile and uniform sized alginate beads, a protocol was standardized for temperature, time and concentration of sodium alginate solution with calcium chloride solution. The optimum concentration of sodium alginate solution and temperature required for alginate beads preparation was 3% and 95 oC for 15 minutes. The diameter of alginate beads ranged between 2 mm – 2.7 mm. The rate of release of nitrogen fixers from alginate based consortia-1 during the initial 24 hours was high (41.67 x 106 cfu -1 g of beads) which reached to a population of 21 x 106 cfu -1 g of beads at 90th day. Population of nitrogen fixers, phosphorus solubilizers and potassium solubilizers decreased towards the 90th day when compared with the initial count of bacteria released from the alginate beads. A pot culture experiment using tomato as a test crop was conducted under sterile and unsterile potting mixture separately to evaluate Alginate based consortia (T1, T2 and T3), combination (T1 + T2 + T3), Talc based consortia (T5, T6 and T7) and POP (T8), Organic POP (T9) and Absolute control (T10). In sterile soil, the population of nitrogen fixers were higher for all the treatments receiving bacterial consortia. The population of P-solubilizers were higher in alginate based consortium-1 (13.0 x 106 cfu g-1) while the population of K-solubilizers were higher in treatments with combined application of alginate based consortia. Under unsterile soil, the population of nitrogen fixers were found to be higher in treatments with alginate and talc based consortia. The population of potassium solubilizers was higher in treatment with combined application of alginate based consortia. Treatments with alginate based consortium showed a higher population of phosphorus solubilizers compared with talc based consortia in unsterile soil. However, the population of N fixers, P and K solubilizers decreased with time in all treatments. Compared to initial soil status, application of alginate based bacterial consortium-1 resulted in a significant increase in available nutrient content among treatments receiving bacterial consortia in sterile soil conditions. Yield and yield attributes were higher in the alginate based bacterial consortia-1(897.0 g/plant) under sterile condition. However, yield was higher in treatment based on POP under unsterile soil conditions (845.0 g/plant). Among alginate based treatments, alginate based consortium-1 recorded a higher yield (707.33g/plant) under unsterile condition also. The present studies indicated that the alginate based consortium could be a potential microbial inoculant formulation which is less bulky, free from contamination, biodegradable and non-toxic. Encapsulation enables slow and controlled release of cells and thus, maintains a uniform bacterial population. However, further studies are required to study its shelf life, its performance under field condition before commercialization and develop a suitable protocol for large scale production.ThesisItem Open Access Utilization of soil health card by the farmers of Thrissur district(Department of Agricultural extension, College of Horticulture, Vellanikkara, 2019) Reshmi, S; KAU; Binoo Bonny, P.Injudicious and hazardous use of chemical fertilizer in agriculture is a matter of concern in recent times. In order to avoid deterioration of soil in the long run and visualizing the importance of balanced nutrition in crop production, Government of India launched the soil health (SHC) programme in 2015. The Soil Health Card provides appropriate guidance to the farmers for the efficient use of fertilizer for crops based on soil health analysis. The SHC is a printed document, which contains data on soil test based chemical analysis to describe soil health in terms of its nutrient availability and its physical and chemical properties. The study was carried out in Thrissur district as it had the maximum number of SHC scheme beneficiaries in the State. A total of 180 respondents from the district formed the sample which constituted 150 farmers and 30 scheme implementing officers. Status of SHC use among farmers revealed the presence of four categories of SHC users viz. participant SHC scheme users, participant SHC scheme non-users, paid SHC users and non-participant non-users. Analysis of the socio-economic variables between the different categories of users and non-users of farmers revealed that the variables, farming experience, exposure to training and irrigation facility showed significant difference among the respondents at 0.05 and 0.01 levels with p values 0.040, 0.016 and 0.001 respectively. With regard to awareness on SHC, Paid SHC users had an overall awareness score of 461.52. On all selected awareness domains they had uniformly high scores except on general information on SHC scheme wherein the score was only 78.00 per cent. Regarding the spread of SHC in Thrisssur district, Chavakkad was the only block that covered more than 50 per cent of farmers. Extent of adoption measured using adoption index, and the results indicated that 50 per cent of the participant SHC scheme users were of medium adoption category, followed by 34 per cent of low adopters and only 16 per cent belonged to the high adoption category. However, in XXXII the case of paid soil test users, it could be inferred that majority of the farmers (60 per cent), came under high adoption category, followed by 33 per cent under medium level of adoption and only 7 per cent belonged to low adoption category. Correlation between the independent variables and adoption of SHC recommendations by participant SHC scheme users and paid SHC users revealed that, irrigation facility and farming experience showed positively significant correlation with adoption at 0.05 level for both the categories. It is also important to find that when scientific orientation recorded positive and significant relation with adoption at 0.01 level for both participant SHC scheme users and paid SHC users, training and education showed significant relation only for the paid SHC users at 0.01 and 0.05 levels of significance respectively. When 90 per cent of the paid SHC users showed favourable perception regarding the reliability of SHCs, only 40 per cent of the participant SHC scheme users displayed a favourable utility perception on the domain. With regard to the quantity of fertilizers (Urea, SSP, MOP) applied, and micronutrient use, there is significant difference between users and non-users with p values 0.44 and 0.017 respectively. Results of binary logistic regression of SHC users and non-users with socioeconomic variables and yield taken as independent variables revealed that a change in the level of education, farming experience, irrigation or yield could bring a corresponding chance of 64, 30, 31 and 67 per cent respectively for a non-user to become a user of SHC results. Majority of farmers (68 per cent) stated that the time gap between soil collection and distribution of cards was too long. The major constraint stated by officers was unavailability of field staffs for taking samples (68.23 per cent). Though the services were free under the scheme, farmers face a lot of impediments in getting full benefits of the scheme. It is suggested that the policy makers should conduct suitable awareness programs and trainings to promote the usage of soil health cards. Follow-up by extension agency, timely reporting of soil test results to farmers is crucial in whole programme. Effective utilization of the scheme also needs the presence of field level experts to clear doubts of farmers at the time of their need in a scientific way.ThesisItem Open Access Somatic embryogenesis from immature inflorescence of coconut (Cocos nucifera L.)(Department of Plant Biotechnology, College of Horticulture, Vellanikkara, 2019) Radhika, R; KAU; Sujatha, RCoconut palm (Cocos nucifera L.), the only species of genus Cocos, is a major crop plant which is propagated exclusively by seeds presently. Coconut is highly heterozygous, generally cross-pollinated and long lived. So the offspring differ greatly due to segregation, which can be assessed only after a very long juvenile phase. Breeding for crop improvement is thus a difficult and long-term process. So within a short period, in- vitro propagation, employing tissue culture techniques, offers a means of cloning improved planting material. So the objective of the study was to assess the in vitro response of immature inflorescence of coconut explants for induction and germination of somatic embryos by supplementing the medium with by-product of neera processing and neera. The media for culture initiation, subculturing and embryo germination were standardised in earlier experiments (Siny, 2006; Sujatha, unpublished data, 2011). In the present experiments, standardised sub-culturing medium with addition of different supplements were tested. Embryogenic calloids and somatic embryos were induced in standardized CM2 media (Y3 basal media containing a combination of 0.5 mgL-1 picloram, 1 mgL-1 NAA and 0.1 mgL-1 TDZ and 300-600 μM 2,4-D) from the immature inflorescence explant. Among the different stage and region of immature inflorescence tested in standardised CM2 medium, tip region of inflorescence (85.71%) with length 1-5 cm was found to be the best for calloid induction with low browning (4.76%). The adverse effect of exudation of polyphenols was reduced by inoculating youngest inflorescence with reduced thickness. Embryogenic calloids were sub- cultured into 10 media combinations. With four stages of explant (based on length), each stage with two types (tip or base) there were eighty combinations. The suitability of the by-product from neera processing as well as neera (CIS- Coconut Inflorescence Sap) as supplements for CM2 medium to culture the immature inflorescence of coconut was assessed and found that CM2 medium with 0.3 per cent activated charcoal, 4 per cent sucrose and 2 per cent supplement and also CM2 medium with 0.3 per cent activated charcoal, 4 per cent sucrose and 10 mlL-1 CIS was the best medium for obtaining cultures with calloid proliferation (92.75 % & 90.17 %) with minimal phenolic interference (11.58 % & 22.7%). Calloid proliferation was successfully achieved from all the media combinations. Chemical properties of neera supplement used in the culture medium
