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ThesisItem Open Access Novel strains of Metarhizium anisopliae sorokin.(Ascomycota:sordariomycetes) with enhanced abiotic stress tolerance(Department of agricultural entomology, college of agriculture, Vellanikkara, 2023-08-02) Sreelakshmi, U K.; KAU; Deepthy, K BNovel strains of Metarhizium anisopliae Sorokin. (Ascomycota: Sordariomycetes) with enhanced abiotic stress tolerance Abstract The green muscardine fungus, Metarhizium anisopliae Sorokin is widely used in the management of various crop pests. However the efficacy of M. anisopliae in the field is often inconsistent, mainly due to the environmental stresses such as temperature extremes, drought, UV radiation, etc. To circumvent these hurdles, the present study was undertaken to develop novel strains of M. anisopliae with enhanced environmental stress tolerance. The Metarhizium isolates, EKM2, CKD, and M4 were collected from the repository maintained at the Department of Agricultural Entomology and were screened for their temperature and drought tolerance. The isolate EKM2 recorded the highest mycelial weight (6.221g), while the isolate M4 recorded the least mycelial weight (0.328 g) and the least sporulation at the highest temperature of 380C. The screening for drought tolerance was conducted at various levels of Polyethylene glycol (PEG) concentrations in which the isolate CKD has shown higher biomass (2.172 g) with higher sporulation, while isolate M4 recorded the lowest mycelial weight (1.336 g) at the maximum PEG concentration of 39 per cent. The three selected isolates of M. anisopliae (CKD, EKM2 and M4) were subjected to further experiments. The Metarhizium isolates (CKD, EKM2 and M4) selected from the preliminary screening were continuously subjected to temperature stress treatments starting from 35oC to 42oC. At the highest temperature of 41oC, the isolate, EKM2 recorded the highest mycelial weight (1.336 g), number of colonies (18.667103 cfu/ml), number of spores (0.783 X 10 7 /ml), spore size (3.470 µm) and mycelial thickness (3.07 µm). At the same temperature, the isolate, M4 recorded the lowest mycelial weight (0.63g), number of colonies (3 cfu/ml), number of spores (0.217 X 10 7 /ml), spore size (1.637 µm), and mycelial thickness (2.65 µm). Hence EKM2 has been identified as the thermo-tolerant isolate and M4 as the susceptible one. The thermo-tolerant isolate EKM2 was grown continuously for 6 successive generations at the same temperature level of 41oC in order to stabilize the stress tolerance. The Metarhizium isolates (CKD, EKM2, and M4) selected from the preliminary drought screening experiment were also continuously subjected to drought-inducing treatments at PEG concentrations starting from 25 to 40 per cent. At the highest level of PEG concentration (40 %), the isolate CKD showed higher mycelial weight (3.365 g), spore count (0.323X 107 /ml)), number of colonies (4 X 103 colonies/ ml), spore size (3.15 µm), and mycelial thickness (2.723µm). The isolate, M4 recorded the lowest mycelial weight (0.808g), number of colonies (2 cfu/ml), spore count (0.243 spores/ml), spore size (4.493 µm), and mycelial thickness (2.543 µm) at the same PEG concentration. Hence isolate CKD is identified as drought tolerant and M4 as susceptible. The drought-tolerant isolate, CKD was grown continuously for 6 successive generations at the same PEG concentration level of 40 per cent in order to stabilize the stress tolerance. The selected tolerant isolates were evaluated against wax moth larva (Galleria mellonella) to identify their biocontrol efficacy. Isolate EKM2 has shown cent per cent mortality at the dosage of 108 and 109 spores/ml on the 9th day after treatment. At the highest dosage of 1x 109 spores/ ml, the isolate CKD recorded a lower LT50 (5.099 days) value, and isolate M4 recorded the highest LT50 (6.124 days) value. The isolates EKM2 and CKD were found to be more virulent while M4 was less virulent. The thermo-tolerant isolate, EKM2 recorded a total protein content of 0.354 mg/ml, and the drought-tolerant isolate (CKD) recorded a total protein content of 0.373 mg/ml. The thermo-tolerant isolate EKM2 has shown a trehalose content of 1.954 mg/min/g tissue weight which was significantly higher compared to the control (1.074 mg/min/g tissue weight). The trehalose content in the drought-tolerant isolate CKD (1.970 mg/min/g) was also higher when compared to the control (1.224 mg/min/g). The catalase activity ranged between 0.237 EU/min/mg proteins in the control to 0.386 EU/min/mg protein in the thermo-tolerant isolate EKM2, while the catalase activity of the drought-tolerant isolate, CKD was 0.384 c protein which was higher when compared to its control (0.240 EU/min/mg protein). The thermo-tolerant isolate recorded a peroxidase activity of 0.0230 EU/min/g tissue and that of droughttolerant isolate CKD was 0.0236 EU/min/g tissue weight. The protease activity of thermo-tolerant isolate CKD was 0.490 EU/min/mg protein and that of the droughttolerant isolate was 0.621 EU/min/mg protein. At 25 minutes of reaction, the thermo-tolerant and drought-tolerant isolates have shown higher lipase activity (10.000 µmol fatty acid/ml and 11.00 µmol fatty acid/ml respectively) when compared to their respective controls. On the 5th day, both the thermo-tolerant and drought- tolerant isolates recorded significantly higher chitinase activity (1.140 µg of N- acetyl glucose amine/min/ml of broth and 3.062 µg of N- acetyl glucose amine/min/ml of broth respectively) than their controls. The temperature induction had up-regulated heat shock proteins of 25 kDa and 35 kDa in heat-induced isolate EKM2. The isolate also expressed heat shock proteins in the range of 100 kDa molecular weight. Drought tolerant isolate (CKD) on the other hand did not show the presence of any heat shock protein when compared to the control. The study could develop isolates of M. anisopliae which are tolerant to temperature and drought stress, with high virulence as well as higher biochemical activityThesisItem Open Access Genetic diversity analysis of rambutan (Nephelium lappaceum L.) accessions using molecular markers(Department of fruit science, College of agriculture ,Vellayani, 2023-09-12) Gazel, M Gaddafi; KAU; Anu, G KrishnanRambutan (Nephelium lappaceum L.) holds great potential in Kerala being a tropical region. It belongs to the Sapindaceae family, which consists of numerous trees and shrubs, comprising over 125 genera and more than 1000 species that are found across the tropics and warm regions. These plants are adaptable to various soil types, ranging from heavy soils in low-lying areas to hilly soils in upland regions. The origin of rambutan can be traced back to Southeast Asia, specifically Indonesia and Malaysia. Rambutan cultivation is rapidly expanding along India's western coast, particularly in the districts of Pathanamthitta, Kottayam, and Thrissur of Kerala. Even though morphological characterization and diversity studies of the collections from various localities in Kerala have been carried out, the genetic diversity analysis using molecular markers has not yet been conducted. Hence, the current research titled "Genetic diversity analysis of rambutan (Nephelium lappaceum L.) accessions using molecular markers" was conducted at the Regional Agricultural Research Station Kumarakom and at the Department of Fruit Science, College of Vellayani between 2020 and 2022. The main objective of this study was to assess the diversity of twenty rambutan accessions using SSR and ISSR molecular markers collected from the districts of Kottayam, Pathanamthitta, and Thrissur. DNA isolation was performed using the CTAB method (Doyle and Doyle,1987) with minor modifications. A pre-washing with sorbitol buffer was done to improve the DNA quality. The DNA samples showed UV absorbance ratios (A260/A280) between 1.80 and 1.95 indicating their purity. The initial primer screening was conducted with thirty ISSR and sixteen SSR primers. Based on their ability to yield reproducible and distinct banding patterns, eleven ISSR and five SSR primers were selected for subsequent analysis. The ISSR primers used in the study exhibited a polymorphism percentage ranging from 55.56% (ISSR 10 ) to 100% (ISSR-1 and UBC 828), with an average value of 79.44%. On the other hand, the selected SSR primers displayed a 100% polymorphism percentage. The Polymorphic Information Content (PIC) values ranged from 0.12 (UBC-819) to 0.41 (ISSR-23) for ISSR markers and from 0.60 (NlaSSR 7) to 0.72 (NlaSSR 23) for SSR markers. PIC is an indication of the informativeness of the primers. The Marker index (MI) which measures the utility of the primers ranged between 0.36 (UBC 819) to 2.88 (UBC 825) for ISSR markers and it varied between 1.80(NlaSSR 7) to 2.88 (NlaSSR 23) for SSR markers. The diversity analysis of rambutan accessions was performed using the NTSYS-Pc software. In the UPGMA (Unweighted Pair Group Method with Arithmetic Mean) cluster analysis based on ISSR data, the rambutan accessions were divided into two distinct clusters at a similarity coefficient of 0.61 with 10 accessions in each cluster. The Col.03 and Col.53 were found to be closely related with a similarity of 71%. In the SSR data-based cluster analysis, the rambutan accessions were divided into two major clusters at a similarity coefficient of 0.70. Cluster I comprised a total of eight rambutan accessions and Cluster II included the remaining twelve genotypes. The highest similarity of 67% was observed between Col.87 and Col.97, Col. 81 and Col.86, Col.04 and Col.52, and Col.48 and Col.15. In the combined SSR-ISSR cluster analysis, at a similarity coefficient of 0.62, the rambutan accessions were divided into two clusters, showing a similar dendrogram pattern as observed in the ISSR data-based dendrogram. The Principal Coordinate Analysis (PCoA) also revealed a similar pattern of distribution of the accessions as recorded in cluster analysis.The results of the present study revealed that the accessions studied had genetic diversity ranging from 61% to 70% under different marker systems. The accessions from the same area have shown a closer genetic distance, suggesting that dispersal from related parents may have occurred. In future crop improvement programmes for this exotic crop, existing germplasm from different locations of the state and molecular analysis employing more markers can be exploited. Identification of markers associated with economically important trails will be useful for marker assisted breeding programmes. The current study on genetic diversity using molecular markers is the first of its type in Kerala and hence can be considered as a basic information for future related works.ThesisItem Open Access Irrigation water: assessing the economic efficiency and its pricing in banana(Department of agricultural economics, college of agriculture, Vellanikkara, 2023-07-24) Midhuna,Sivanandan; KAU; Hema, MWater has distinct properties that influence both its allocation and use as a valuable resource in agriculture. Irrigation is a critical component of agricultural production. According to the UNESCO World Water Development Report (2022), India is the world's top groundwater extractor. About 80 per cent of all withdrawals are made in the agricultural sector, and India has a low irrigation efficiency of 38 per cent when compared to developed nations (GoI, 2018). When water, the elixir of life, is becoming scarce due to over exploitation, increasing or at least maintaining its efficient use is imperative. In order to achieve effective and equitable use, the Fourth Principle of the Dublin Declarations of 1992 defines water as an economic good. It encourages the conservation and protection of water resources. With the adoption of the Fourth Dublin Principle, there was a historic shift in the focus on the economic aspects of water use in general and irrigation development in particular. Numerous researchers have looked into water valuation as a tool for managing irrigation systems, reducing water consumption, and improving water allocation. Hence, evaluating irrigation water's economic effectiveness and value becomes relevant in the current scenario. It is in this context, the study was carried out with specific objectives viz., identifying the sources of irrigation, private investments for irrigation and irrigation pattern, estimating the economic efficiency of irrigation water and making an assessment of its pricing. The study was based on primary data collected from Kodakara and Chalakkudy blocks of Thrissur district owing to their maximum share of cropped area under banana and groundwater extraction in the respective blocks. 60 farmers from each blocks using pump irrigation as a source of irrigation in banana cultivation are randomly sampled to make a total of 120 sample respondents. The sources of irrigation in the study area were found to be wells, tube wells, ponds, canals, and rivers, wherein most of the farmers relied on wells for their irrigation. I The irrigation pattern of the study area included surface irrigation, drip irrigation, and sprinkler irrigation. Most farmers use surface irrigation method due to its easy management. Drip and other micro-irrigation techniques were less adopted due to their high initial investment costs and maintenance problems. The Private investment for banana farmers cultivating banana on owned and leased land was calculated by considering depreciation and miscellaneous costs. It accounted for Rs. 19,479 per hectare for owned land and Rs. 8,183 per hectare for leased farmers. The cost of cultivation for banana cultivation was worked out separately for owned and leased farmers using ABC cost concepts. The total cost of banana cultivation was found to be Rs. 4,80,877 per hectare (owned land) and Rs. 5,04,066 per hectare (leased land) with net returns of Rs. 2,61,981 and Rs. 3,22,089 per hectare, respectively. The benefit- cost ratios were found to be stable, with 1.5 (owned land) and 1.6 (leased land), respectively. The determinants of yield in banana cultivation were analyzed using the Cobb- Douglas production function. The yield of banana was regressed with different variables like the quantity of irrigation water applied, manures and fertilizers, human labour and plant protection. It was found that the quantity of irrigation water, manures and fertilizers and human labor as the major determinants of banana cultivation. The economic efficiency of irrigation water in the study area was assessed using Data Envelopment Analysis Program. The analysis showed that the technical, allocative and economic efficiencies had a mean values of 60.9, 87.1, and 53 per cent. Analysis revealed that there exists scope for increasing the efficiency of irrigation water in the study area. The average quantity of irrigation water currently used in the study area was 2.4x103 per hectare for 1373 plants per hectare, which was compared with the study results carried out in Agricultural Research Station, Chalakudy, to determine whether irrigation water is being overused or underused. The study was conducted during 2009- II 2014 on system intensification for better water productivity in banana (Nendran) (ARS Chalakudy, 2021). The study results showed that irrigating crops at 100 per cent irrigation (10 mm CPE- Cumulative Potential Evaporation), i.e., 20 liters of water per plant per day, is required for the banana to increase the bunch yield per plant significantly. The study found that the water required was 1.3 x 103 m3 per hectare (1373 plants/ha). On comparing it with the results of the present study, an overuse of 1.1 x 103 m3 per hectare was found in the study area. It is mainly attributed to the surface irrigation method followed in the study area. The marginal pricing of irrigation water under the study area was analyzed using the Cobb-Douglas production function, and the marginal value was found to be Rs. 22.31 per m3. The ratio of MVP to MFC for the quantity of water applied was also found to be 0.8, which indicated the overutilization of the irrigation water applied. Thus, the farmers in the study area are currently overutilizing the irrigation water, and the mean economic efficiency of the farm was only 53 per cent, wherein improvement can be made by promoting the use of micro-irrigation technologies such as drip instead of surface irrigation. Also, promotion of extension and awareness activities relating to water harvesting, irrigation scheduling, water management, and crop alignment for farmers and grass root level field functionaries has to be carried out to enhance the irrigation efficiency of the farms in the study area.ThesisItem Open Access Preservation of coconut wood using inorganic nanoparticles(Department of forest products and utilization , college of forestry,Vellanikkara, 2023-12-22) Sidhartha, T N; KAU; Vishnu, RCoconut is a vital crop of Kerala, potential substitute for conventional timber. However, it is susceptible to termites, red palm weevils, bark weevils, shot hole or bark borers, and other pathogens. Traditional wood preservatives like Chromated Copper Arsenate and Chromated Copper Borate pose environmental risks. To address these challenges, researchers are exploring the concept of nanotechnology as a potential solution for wood protection. Nanoparticle has high efficiency to maintain wood natural color, and controlled release of active ingredients at a low concentration, making them a priority for future wood protection applications. As there is limited research on coconut's durability, degradability, and biocide properties of nanoparticles study has been conducted to understand the same. The copper and zinc nanoparticle was prepared by chemical reduction and precipitation method respectively. Medium and high density coconut wood was impregnated with this nanoparticles at 1%, 2.5% and 5% concentration. Two method of impregnation was carried out i.e., coating with fixative and pressure without fixative. Later, these samples were undergone chemical retention test, leaching test, subterranean termite test, weatherability test and water absorption test according to various standards of ASTM and AWPA. Nested anova was carried out to know the significant difference among various factors and their levels. Chemical reduction and precipitation method of copper and zinc nanoparticle preparation yielded 65.06% and 70.15% respectively. The SEM image of copper and zinc nanoparticles confirmed to have irregular cuboidal and flake shape with average size of 173.66 nm and 105.44 nm respectively. The presence of copper and zinc in the nanoparticles was verified by EDX analysis. The presence of the corresponding nanoparticles' metal-hydroxyl and metal-oxide groups was verified by the FTIR spectrum. XRD analysis shows that most of the copper in copper nanoparticles is present as copper oxide and cuprous oxide whereas, zinc nanoparticles as zinc oxide. The chemical retention of both pressure and coating treatment had significantly varied among various density, and nanoparticle concentrations. Among density, medium density had shown higher retention than high density. Concentration of 5% zinc and 5% xxix copper treated to medium density had shown greater retention among various nanoparticle concentration. The chemical leaching test showed that high leaching of nanoparticles occurred during initial stage. Pressure treated coconut wood with nanoparticles statistically varied between various density, nanoparticle and its concentration. High density had shown low leaching compared to medium density. Among nanoparticle and its concentration, zinc has shown the least leachability when compared to control. Same trend was seen in coating method. The subterranean termite test (no-choice) shown significant variation for mass loss and visual appearance among various density, and nanoparticles. While there was no significant difference seen with respect to different nanoparticle concentrations. Among density class medium was susceptible to termite attacks. Copper treated sample shown significant resistant to termite damage when compared to zinc treated sample. Statistically significant variation among density, nanoparticle and its concentration was seen in a weatherability test. High density sample was least susceptible to mass loss and greying. Zinc and copper treated sample shown excellent resistant to mass loss and greying as compared to control. Water absorption test shows a remarkable variation among density, nanoparticle and its concentration in the coconut wood treated by pressure and coating. Medium density shown greater water absorption and volume swelling percentage. Among nanoparticles, control shown more water absorption and volume swelling percentage. Hence, nanoparticles in wood preservation offer improved durability and performance due to their small size and unique properties. They offer enhanced resistance to leaching, termites, and other environmental factors, leading increased lifespan for wood-based products. However, further research is needed to ensure the safe and responsible application of nanoparticle-based wood preservation technologies, while considering cost and scalability.ThesisItem Open Access Expression profiling of E2F and CDKA during embryo culture in coconut(Cocos nucifera L.)(Department of plant biotechnology, college of agriculture, Vellanikkara, 2023-08-05) Mounika Sai, K.; KAU; Smita, NairThe study entitled “Expression profiling of E2F and CDKA genes during embryo culture in coconut (Cocos nucifera L.)” was undertaken at the Department of Plant Biotechnology, College of Agriculture, Kerala Agriculture University, Vellanikkara, Thrissur. The objective of the study was, expression profiling of the genes governing organogenic regeneration pathway at different morphogenic response stages in coconut embryo culture. This chapter provides the key insights of the study.ThesisItem Open Access Bioefficacy of Tagetes minuta L. against Teranychus truncatus ehara (Prostigmata: Tetranychidae) and Aphis craccivora koch (Hemiptera: Aphididae)(Department of Agricultural Entomology, College of Agriculture, Vellanikkara, 2023-03-25) Ashish V V.; KAU; Haseena, BhaskarThe spider mite, Tetranychus truncatus Ehara and the black cowpea aphid, Aphis craccivora Koch are two predominant sucking pests infesting several vegetable crops in Kerala. Farmers depend heavily on chemical pesticides for the management of these pests. However, due to the adverse effects of synthetic pesticides on environment and non-target organisms, there is a growing need for environmentally benign alternatives. This has generated interest in the development of biopesticides, based on botanicals. Tagetes minuta L., commonly known as Mexican marigold or wild marigold or southern cone marigold is a plant whose pesticidal properties have been well documented. The study was carried out in the Department of Agricultural Entomology, College of Agriculture, KAU, Vellanikkara during 2020-2022. The objectives of the study were to identify the bioactive fractions of T. minuta and to evaluate the bioefficacy of the solvent fractions against T. truncatus and A. craccivora. Tagetes minuta plants cultivated in the Department of Floriculture and Landscaping, were harvested at the flowering stage followed by shade drying and grinding. The powdered botanical was extracted sequentially using hexane (non-polar), chloroform (medium polar) and water (highly polar) as solvents. The hexane, chloroform and aqueous fractions of T. minuta were evaluated for their efficacy against T. truncatus and A. craccivora in the laboratory at five different concentrations viz., 0.025, 0.05, 0.1, 0.15 and 0.2 %. The ovicidal and adulticidal effects of the solvent fractions were evaluated against T. truncatus by topical application method. Considerable ovicidal action was exhibited only by hexane fraction at higher concentrations (0.1, 0.15 and 0.2 %), with cent per cent egg mortality at 0.2 %, after 120 h of treatment. However, all the three solvent fractions caused appreciable mortality of adult mites, in a concentration dependent manner. The hexane fraction at 0.2 % and 0.15 % were significantly superior, causing 91.67 and 90.00 per cent mortality, respectively, followed by 0.2 % chloroform (66.67), 0.15 and 0.10% (56.67), and 0.2 % aqueous fraction (53.33), after 120 h of treatment. The efficacy of the solvent fractions (0.025, 0.05, 0.1, 0.15 and 0.2 %) against A. craccivora was evaluated in the laboratory on cowpea seedlings grown in paper cups. Though the highest reduction in aphid count after 120 h of treatment was recorded in hexane fraction at 0.2 % (90.00 per cent), chloroform (86.67) and aqueous fraction (85.00) also recorded reduction in aphid count on par with it, at the same concentration. Qualitative phytochemical analysis of the hexane and chloroform fractions was carried out by GC-MS/MS to identify the major bio- active constituents. The two compounds, 4-o-methylphorbol 12, 13- didecanoate and milbemycin b were found in both the fractions, while 4α-phorbol 12,13-didecanoate was found in hexane fraction only. The best concentrations of the three botanical fractions of T. minuta were tested for efficacy against T. truncatus on potted plants of amaranthus along with neem oil emulsion (2%) and horticultural mineral oil (2.5%). After 14 days of treatment, the hexane fraction recorded the highest reduction in mite population (88.78 %) followed by chloroform and aqueous fractions which were on par with each other (77.97 and 76.96 %, respectively). Hexane fraction was superior to neem oil emulsion, while chloroform and aqueous fractions were found to be on par with neem oil emulsion (76.44), which is a widely recommended botanical preparation for mite pest management in different crops. The best concentrations of the three solvent fractions of T. minuta identified in the laboratory study were evaluated against A. craccivora on cowpea, in a pot culture experiment. By 10th day of treatment, the field efficacy of hexane fraction (78.95 % reduction) was comparable with that of neem oil emulsion (87.59 %), while chloroform (72.43 %) and aqueous fractions (68.20 %) were comparable with azadirachtin 1 EC (67.97 %). The results of the study indicate that Mexican marigold possess excellent acaricidal and insecticidal properties and that the plant can be explored further, for utilization in the management of spider mites as well as aphids.ThesisItem Open Access Biomineral enriched composts (BOKASHI) - a tool for enhancing nutrient availability and enzyme activity in Rhizosphere(Department of soil science and agricultural chemistry, college of agriculture, Vellayani, 2023-08-05) Shilpa, S.; KAU; Aprna, BBiomineral enriched composts (Bokashi) – A tool for enhancing nutrient availability and enzyme activity in rhizosphere The study entitled “Biomineral enriched composts (Bokashi) – A tool for enhancing nutrient availability and enzyme activity in rhizosphere” was carried out during 2020-22 in the Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani. The objective of the study was the production and evaluation of biomineral enriched composts for enhanced nutrient availability, yield of test crop (Bhindi) and enzyme activity in the rhizosphere. The study comprised of three parts viz., production and characterization of biomineral (Bokashi) composts from different organic sources, soil incubation study for evaluating the nutrient release pattern and field experiment for evaluating the performance of the biomineral enriched (Bokashi) compost. Bokashi composts were prepared from two substrates S1 (Aquatic weed Limnocharis flava) and S2 (Aquatic weed Limnocharis flava and banana pseudostem in 1:1 ratio). The substrates were allowed to ferment anaerobically using EM solution and the matured composts were enriched with three minerals like M1 (Calcium apatite), M2 (Epsom salt) and M3 (Sylvinite) at 2% rate in different combinations. The design followed was Completely Randomized Design with 14 treatments replicated thrice. The treatment combinations were T1 – Bokashi compost prepared from L.flava enriched with calcium apatite, T2 - Bokashi compost prepared from L.flava enriched with epsom salt, T3- Bokashi compost prepared from L.flava enriched with sylvinite, T4 –Bokashi compost prepared from 1:1 mixture of L.flava and banana pseudostem enriched with calcium apatite, T5 - Bokashi compost prepared from 1:1 mixture of L.flava and banana pseudostem enriched with epsom salt, T6 - Bokashi compost prepared from 1:1 mixture of L.flava and banana pseudostem enriched with sylvinite, T7- Bokashi compost prepared from L.flava enriched with calcium apatite and epsom salt, T8 - Bokashi compost prepared from L.flava enriched with epsom salt and sylvinite, T9 - Bokashi compost prepared from L.flava enriched with calcium apatite and sylvinite, T10 - Bokashi compost prepared from 1:1 mixture of L.flava and banana pseudostem enriched with calcium apatite and epsom salt, T11 - Bokashi compost prepared from 1:1 mixture of L.flava and banana pseudostem enriched with epsom salt and sylvinite, T12 - Bokashi compost prepared from 1:1 mixture of L.flava and banana pseudostem enriched with calcium apatite and sylvinite , T13 – Bokashi compost prepared from L.flava enriched with calcium apatite, epsom salt and sylvinite and T14 - Bokashi compost prepared from 1:1 mixture of L.flava and banana pseudostem enriched with calcium apatite, epsom salt and sylvinite. To all the treatments (T1 – T4) zeolite was added at a rate of 0.5%. The physico-chemical and biological properties of the produced composts were subjected to analysis. Based on the analysed parameters like major and minor nutrient, enzyme activity, C:N ratio, fertilizing index the best seven composts selected for incubation study and field experiment were T2, T7 , T10, T11, T12, T13 and T14. Among these T13 (Bokashi compost prepared from L.flava enriched with calcium apatite, epsom salt and sylvinite) was selected as the best compost with the highest values of nitrogen, phosphorous, micro nutrients and enzyme activity while the lowest value of C:N ratio was also reported by T13. In part 2 of the study a soil incubation was carried out to investigate the nutrient release pattern of selected composts. The design followed is CRD with 8 treatments which was replicated thrice. One kg soil was incubated at field capacity for four months. The treatments were T1 - Absolute control, T2 to T8 - selected best seven composts. The treatments were imposed at surface of the soil at 20 g kg-1 and thoroughly mixed. Soil sample was drawn at 1st, 4th, 8th, 12th and 16th week of incubation and analysed for organic carbon, P, K, Ca, Mg, S, Fe, Mn, Zn, Cu, dehydrogenase and cellulase activity. From the study, it was observed that nitrogen, phosphorous, potassium, calcium, sulphur, iron, copper, organic carbon and enzyme activity were found to be maximum at the 4th week of incubation. Zinc content was observed to be maximum during 12th week of incubation while magnesium content was highest during 16th week of incubation. Manganese availability was maximum during 8th week of incubation. In part 3 of the study a field experiment was conducted from February – May 2022 with Bhindi (var. Anjitha) as the main crop and Amaranthus (var. Arun) as the residual crop. In the field experiment 9 treatments were imposed viz. T1 - Absolute control, T2 to T8 – selected best seven composts and T9¬ - KAU POP recommendation. Analysis of postharvest soil for chemical properties revealed that the highest value of organic carbon (1.14 %) and nitrogen (319.86 kg ha-1) was recorded for T7. The highest value for available phosphorous (91.65 kg ha-1) was recorded for T8 which was on par with T6 (89.67 kg ha-1) and T7 (88.59 kg ha-1). The potassium content was found to be the highest for T6 (273.91 kg ha-1) which was on par with T8 (270.60 kg ha-1). T7 recorded the highest values of iron (48.54 mg kg-1), zinc (4.79 mg kg-1), copper (1.88 mg kg-1) and boron (0.832 mg kg-1). While manganese (25.62 mg kg-1) was reported to be the highest with regard to T8. The highest value of cellulase activity was recorded by T7 (45.53 µg glucose hydrolysed g-1 soil h-1) while T8 recorded the highest value of dehydrogenase activity (302.68 µg of TPF hydrolysed g-1 of soil 24 h-1). Analysis of rhizosphere soil showed the highest value of microbial biomass carbon (91.14 mg kg-1 soil), glomalin (14.27 mg g-1), humic acid (9.21 %), fulvic acid (9.98), fungi (5.52 log cfu g-1), actinomycetes (5.16 log cfu g-1) and soil respiration (4.17 mg CO2 g-1) for T7 while T8 recorded highest value for bacteria (7.90 log cfu g-1). T7 recorded the highest value for number of fruits per plant (30.67) which was on par with T5, T6, and T8. Fruit girth was found to be the highest for T7 (5.06 cm) which was on par with T6, T8 and T9. T7 also recorded the highest value for fruit length (23.81 cm), yield per plant (570.42 g) and total yield (21.05 t ha-1). The highest B: C ratio (2.26) was reported by T7. The highest yield of amaranthus (130.23 kg ha-1) was recorded for T7. From the study, T13 (Bokashi compost prepared from L.flava enriched with calcium apatite, epsom salt and sylvinite) was concluded as the best compost. T7 (Bokashi compost prepared from L. flava enriched with calcium apatite, epsom salt and sylvinite) and T8 (Bokashi compost prepared from the 1:1 mixture of L.flava and banana pseudostem enriched with calcium apatite, epsom salt and sylvinite) recorded the highest values for the available nutrient status during incubation period like nitrogen, phosphorous, magnesium, sulphur, iron, manganese, zinc, copper, organic carbon and enzyme activity. Considering both the soil parameters and yield parameters T7 (Bokashi compost prepared from L. flava enriched with calcium apatite, epsom salt and sylvinite) was recorded as the best treatment.ThesisItem Open Access Carrier based slow release fertilizer formulations for sustained nutrient release and enhanced crop production(Department of soil science and agricultural chemistry, Vellayani, 2023-08-10) Farha, M K.; KAU; Gladis, RThe study entitled “Carrier based slow release fertilizer formulations for sustained nutrient release and enhanced crop production” was conducted at the Department of Soil Science, College of Agriculture, Vellayani during the year 2022. In this study slow release fertilizer formulations were prepared, characterized and investigated for its nutrient release characteristics through leaching experiment with soil column and incubation study. Based on the stability and sustained release of nutrients throughout the leaching and incubation study, best formulations were selected and evaluated. A pot culture experiment was conducted in a completely randomized design replicated thrice using chilli variety Vellayani Athulya as test crop and evaluated the effect of slow release fertilizer formulations on nutrient availability, uptake, use efficiency, yield and quality of chilli. Carrier based slow release fertilizer formulations containing major, secondary and micro nutrients were prepared using compatible fertilizer sources (urea, rajphos, muriate of potash, phosphogypsum, magnesium sulphate, zinc sulphate and borax), carrier materials (zeolite, humic acid, charcoal, chitosan and nano zeolite) and binding/stabilizing agent carboxy methyl cellulose (CMC). The slow release fertilizer pellets prepared were, T1 - Fertilizer mix: Zeolite+ CMC (1:1), T2 - Fertilizer mix: Zeolite+ CMC (1:0.5), T3 - Fertilizer mix: humic acid+ CMC (1:1), T4 - Fertilizer mix: humic acid+ CMC (1:0.5), T5 - Fertilizer mix: charcoal+ CMC (1:1), T6 - Fertilizer mix: charcoal+ CMC (1:0.5), T7 - Fertilizer mix: chitosan+ CMC (1:1), T8 - Fertilizer mix: chitosan+ CMC (1:0.5), T9 - Fertilizer mix: nano zeolite+ CMC (1:1), T10- Fertilizer mix: nano zeolite+ CMC (1:0.5). The pellets prepared were found to be stable, disintegration time 9-13 hours, moisture 5.75- 8.68 %, pH 6.37- 6.90, EC 17.25- 23.17 dSm-1 , bulk density 0.5-0.58 Mg m-3 and weight 4.0- 4.5 g. They contained 8.21 to 9.02 % nitrogen, 5.36 to 5.76 % phosphorus, 3.0 to 3.50% potassium, 5.40 to 5.68 % calcium, 2.01 to 2.86 % magnesium, 4.10 to 5.30 % sulphur , 1.2 to 1.6 % zinc and 0.17 to 0.23 % boron. A soil column experiment was conducted for two weeks to study the nutrient leaching and to confirm the slow release tendency of formulations. The results showed a gradual increase in the release of nutrients from 2 to 14 days of leachate collected from slow release formulations while, fertilizer mix alone showed increasing trend initially and later decreased. A laboratory incubation study was carried out to investigate the nutrient release patterns of the formulations after addition to soil. The results revealed that the pH of soil remained acidic (5.30- 6.17) throughout the incubation period and the EC was found to be increasing from 0.11- 1.45 dSm-1 . The release of nutrients in soil was found to be increasing gradually from 0 to 90 days of incubation with maximum concentration was observed on 90th day for all the nutrients. Based on the stability of pellets and the release of nutrients throughout the leaching and incubation experiment three promising formulations were selected for the pot culture experiment. They were, T2 (FM: Z+CMC 1:0.5), T4 (FM:HA+CMC 1:0.5) and T5 (FM: CC+CMC 1:1) . The treatments of pot culture experiment were T1 -100% RDF as SRF 1 (FM: Z+ CMC -1:0.5) applied as basal,T2 -100% RDF as SRF 1 (FM: Z+ CMC -1:0.5) applied in two splits (basal & 1 MAP), T3 -75% RDF as SRF 1 (FM: Z+ CMC -1:0.5) applied as basal, T4 -75% RDF as SRF 1 (FM: Z+ CMC -1:0.5) applied in two splits (basal & 1 MAP), T5 -100% RDF as SRF 2 (FM: HA+ CMC -1:0.5) appliedas basal, T6 -100% RDF as SRF 2 (FM: HA+ CMC -1:0.5) applied in two splits (basal & 1 MAP), T7-75% RDF as SRF 2 (FM: HA+ CMC -1:0.5) applied as basal, T8 -75% RDF as SRF 2 (FM: HA+ CMC -1:0.5) applied in two splits (basal & 1 MAP), T9-100% RDF as SRF 3 (FM: CHAR+ CMC -1:1) applied as basal, T10-100% RDF as SRF 3 (FM: CHAR+ CMC -1:1) applied in two splits (basal & 1 MAP), T11-75% RDF as SRF 3 (FM: CHAR+ CMC -1:1) applied as basal, T12-75% RDF as SRF 3 (FM: CHAR+ CMC -1:1) applied in two splits (basal & 1 MAP), T13-Soil test based POP recommendation, T14- Control (No fertilizers). The analysis of post harvest soil showed the highest content of available N (320.8 kgha-1 ), P (87.15 kgha-1 ), K (214.3 kgha-1 ), Ca (351.1 mg kg-1 ), Mg (106.5 mg kg-1 ), S (9.32 mg kg-1 ), Zn (4.25 mg kg-1 ) and B (0.46 mg kg-1 ) in T8 receiving 75% RDF as SRF 2 (FM: HA+ CMC -1:0.5) applied in two splits (basal & 1 MAP). With regard to nutrient content and uptake, the treatment T8 registered the highest value. The growth and yield parameters like plant height (56.52 cm), number of branches per plant (9.5), number of fruits per plant (56.70), fruit length (13.44 cm), fruit girth (6.89 cm), fruit weight (11.03), fruit yield (581.2g plant -1 ) and total dry matter production (89.07 g) were found to be the highest in T8. Quality parameters of chilli such as ascorbic acid and capsaicin content were also found to be the highest in T8.The fertilizer use efficiency, agronomic efficiency, apparent recovery of major nutrients and partial factor productivity were found to be the highest recorded in treatment T8.The highest B:C ratio of 2.41 was recorded by treatment T8. Slow release fertilizer formulations containing macro and micro nutrients can be prepared using compatible fertilizer materials (urea, rajphos, MOP, phosphogypsum, magnesium sulphate, zinc sulphate and borax), carrier agents(zeolite, humic acid, charcoal, chitosan and nanozeolite) and binding agent (CMC). The slow release fertilizer pellets were found to be superior with respect to stability, disintegration time, nutrient content and release of nutrients. From the results it can be concluded that the slow release fertilizer formulations containing fertilizer mix: humic acid+ CMC in the ratio of 1:0.5 applied at 75% RDF in two splits as basal & 1 MAP was able to significantly increase the yield, uptake of nutrients, NUE, B:C ratio and quality of chilliThesisItem Open Access Molecular characterization of promising isolates of trichoderma spp. and their field evaluation against fusarium wilt of vegetable cowpea(Department of plant pathology, college of agriculture,Vellayani, 2023-08-07) Jeevidha, M; KAU; Sible, George VargheseThe present study entitled “Molecular characterization of promising isolates of Trichoderma spp. and their field evaluation against Fusarium wilt of vegetable cowpea” was conducted at the Department of Plant Pathology, College of Agriculture, Vellayani during 2020-2022. The study aimed at molecular characterization of potential Trichoderma isolates and their evaluation against Fusarium wilt of vegetable cowpea under field conditions. Five potent isolates of Trichoderma viz., TRMW-2, TRKR-2, TRPN-3, TRPN-11 and TRPN-17 were obtained from the previous study. The analysis of Trichoderma isolates for cell wall degrading enzymes like chitinase, protease and lipase revealed that TRPN-17 recorded the highest chitinase activity of 88.38 U ml-1 . Protease activity was found to be higher in TRPN-11 (165.86 U ml-1 ) whereas highest lipase activity was exhibited by TRPN-3 (4.86 U ml-1 ). The compatibility test among the five isolates showed that all the combinations exhibited antibiosis, lysis and overgrowth except the isolates TRPN-3 and TRPN-11 which displayed only overgrowth. A mild level of antibiosis and overgrowth was observed in the combination of the isolates TRKR-2 and TRPN-17. Assessment of competitive saprophytic ability of the Trichoderma isolates showed that per cent colonization of TRKR-2 was found to be higher (67.50 %) than other isolates and was followed by TRPN-3 and TRPN-17 (56.25 %) with no significant difference among all five isolates. In vitro screening of Trichoderma isolates by dual culture technique revealed that the per cent inhibition of TRPN-17 (63.71 %) was found to be higher, followed by TRKR-2 (58.76 %) and TRPN-3 (58.21 %). Based on the in vitro studies the effective isolates TRKR-2, TRPN-17, TRPN-3, consortia of isolates TRKR-2 and TRPN-17 and consortia of isolates TRPN-3 and TRPN-17 were selected for the in vivo evaluation against Fusarium wilt of vegetable cowpea. Molecular characterization of the isolates were done using the primers for Internal Transcribed Spacer (ITS) regions 1 and 4. All the five isolates produced a single, intact amplicon of size 600 bp approximately. The nucleotide sequences of all the ITS PCR products obtained from the five isolates were confirmed through bidirectional sequencing using the Sangers DNA sequencing. The best match of the amplified sequences was obtained from the GenBank database using NCBI-BLAST and their phylogenetic positions were explored along with the referral sequences from BLAST analysis. The oligonucleotide set of genus-specific primer TvP was used for genus-specific PCR analysis and an amplicon of approximately 245 bp was obtained. The DNA barcoding of the amplicon confirmed the genus identity of all the isolates as Trichoderma. The species-specific identification tried with translational elongation factor- 1 (tef1) and RNA polymerase II (rpb2) gene specific primers did not yield any amplicon indicating that the isolates did not belong to the species T. virens, T. longibrachiatum, T. harzianum and T. asperellum. Application of talc-based formulations of the isolates TRKR-2, TRPN-3, KAU strain and consortium of TRPN-3 and TRPN-17 as seed treatment @ of 20 g kg-1 of seed followed by soil drenching @ 2 per cent at 20, 40 and 60 DAS effectively reduced the incidence of Fusarium wilt of vegetable cowpea in pot culture study. The application of isolate TRPN-3 produced highest pod number (19) in pot culture experiment and also yield per plant (369.57 g) on par with the yield per plant produced by consortia application of TRPN-3 and TRPN-17 (344.52 g). Under field conditions, the disease was most effectively reduced by isolates TRKR-2, TRPN-3, KAU strain and consortia of TRKR-2 and TRPN-17. Lengthy pods (48.16 cm) and highest number of seeds per pod (21.73) were recorded by the application of consortium of TRPN-3 and TRPN-17 whereas application of TRPN-3 resulted in highest yield (1172.63 g/plant), number of pods per plant (19) and reduced days of flowering. Enumeration of population of Trichoderma spp. from soil in different treatments at 90 DAS revealed that, highest population was in treatment with isolate TRPN 3 under pot culture (7 ×104 cfu g-1 ) and field conditions (4 ×104 cfu g-1 ) . In the present study, Trichoderma isolates TRKR-2, TRPN-3, and consortium of TRPN-3 and TRPN-17 were found effective against Fusarium wilt of vegetable cowpea under field conditions. The genus of the isolates under study was identified as Trichoderma. The efficacy of the isolates against other soil-borne diseases of vegetable cowpea and species level identification need to be explored
