PhD Thesis
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Item Bio-fertilizer adoption behaviour of farmers in Pananchery panchayath(College of Co-operation, Banking & Management, Vellanikkara, 2022-06-16) Reshma, K R; Arularasan, G SItem Consumer behaviour towards feminine hygiene products with reference to eco-friendly menstrual cups(College of Co-operation, Banking & Management, Vellanikkara, 2022-06-17) Anjali Das, E S; Sreedev KesavanItem Strain improvement of Trichoderma spp.for management of foot rot of black pepper caused by phytophthora capsici(Department of plant pathology, College of Agriculture, Vellanikkara, 2025-09-22) Alby John; Susha S TharaThe research work entitled ‘Strain improvement of Trichoderma spp. for management of foot rot of black pepper caused by Phytophthora capsici’ was conducted at Department of Plant Pathology, College of Agriculture, Vellayani during 2022-2025 with an objective of enhancing the antagonistic potential and growth promotion of Trichoderma strains by protoplast fusion and mutagenesis; studying the biochemical and molecular mechanisms underlying antagonism and evaluation of its efficacy for managing P. capsici. Five promising isolates of Trichoderma spp.: TRMW-2, TRKR-2, TRPN-3, TRPN-11 and TRPN-17, previously collected from different agroclimatic zones of Kerala, along with Trichoderma asperellum, the reference culture from KAU were used as the parental isolates. Molecular characterization using species-specific primers (TEF1 and RPB2) and multi-gene phylogenetic analysis identified TRMW-2, TRKR-2, TRPN 3, TRPN-11 and TRPN-17 as Trichoderma brevicompactum [Tb], Trichoderma koningiopsis [Tk], Trichoderma pholiotae (PN3) [Tp (PN3)], T. pholiotae (PN11) [Tp(PN11)] and Trichoderma guizhouense [Tg], respectively. A total of 15 protoplast fusion combinations were performed using the six parental isolates and 30 fusants with a colony diameter exceeding 8.5 cm at 48 h were screened. Among these, the 10 most effective fusants, exhibiting a growth inhibition rate of 85.73% to 92.13% against P. capsici were selected based on their mycelial growth suppression. Simple sequence repeat (SSR) marker analysis was performed using 15 primers to determine whether the selected fusants were interspecific. Similar amplification patterns were observed between the fusants Ta × Tk-1, Tk × Tp (PN3)-1, Ta × Tp (PN3)-1 and Ta × Tp (PN3)-5 and their respective parental strains for the markers PRB ATC, TV1, KON 700, TA4, TA9 and TH5, confirming them as interspecific fusants. Strain improvement through UV irradiation (5, 10 and 15 min) exhibited an inverse correlation between exposure time and the number of regenerated colonies. Among 140 mutants screened, 30 with a colony diameter greater than 7.5 cm at 48 h were selected, which were further narrowed down to 10 with the highest inhibition rates of 80.87% - 84.47% against P. capsici. Similarly, gamma irradiation (150, 200, 250 and 300 Gy) showed a negative correlation between colony regeneration and radiation dose. Among 180 mutants screened, 10 superior mutants with a growth inhibition of 81.67% - 90.40% were selected. From the 30 improved Trichoderma spp. strains obtained through three distinct strain improvement techniques, the 10 most effective strains exhibiting significant pathogen inhibition (83.73% to 93.60%) were identified and subjected to genetic stability assessment via ten successive subculturing rounds, followed by dual culture assay against P. capsici. The five most promising Trichoderma strains: T. asperellum × T. koningiopsis-1 [Ta × Tk-1], T. koningiopsis ×T. pholiotae (PN3)-1 [Tk × Tp(PN3)-1], T. pholiotae (PN11) fifth UV mutant colony irradiated for 5 min [Tp(PN11).5m5], T. pholiotae sixth gamma mutant colony irradiated at 200 Gy [Tp(PN3).200m6] and T. asperellum first gamma mutant colony irradiated at 250 Gy [Ta.250m1] with superior mycelial growth suppression (83% to 91.27%) were selected. Culture filtrate assay at 50% concentration revealed maximum mycelial inhibition of P. capsici by Tk × Tp(PN3)-1 (98.33%) and Tp(PN11).5m5 (97.92%). Additionally, Ta × Tk-1 (76.13%) and Tp(PN3).200m6 (72.25%) exhibited significant volatile metabolite activity against P. capsici, outperforming T. asperellum (59.88%). The potential of the selected Trichoderma spp. strains to produce lytic enzymes, including β-1,3 glucanase, protease, chitinase and lipase was evaluated. Ta × Tk-1, Tk × Tp(PN3)-1, Tp(PN11).5m5 and Ta.250m1 exhibited higher enzymatic activity than T. asperellum, signifying enhanced antagonistic potential. Growth promoting attributes, including IAA (174.41 μg ml-1) and siderophore production (77.09%) were highest in the interspecific fusant Ta × Tk-1, while phosphate solubilization was most pronounced in the gamma mutant Ta.250m1(1326.90 μg ml-1). Cultural and morphological characterization of the improved strains revealed distinct variations in conidiation, pigmentation, hyphal width and conidial and phialide size compared to their parental isolates. Notably, Tp(PN3).200m6 exhibited deep yellow pigmentation, while Ta × Tk-1 and Ta.250m1 showed dense sporulation. Pot culture experiments were conducted to evaluate the biocontrol efficacy and plant growth promoting potential of five promising Trichoderma spp. along with T. asperellum in black pepper var. Panniyur - 1. Biometric characters (plant height, number of leaves, nodes and internodal length) were highest in plants treated with Ta × Tk-1, followed by Ta.250m1. Upon challenge inoculation with P. capsici, lesion size was smallest in plants treated with Tk × Tp(PN3)-1 and Tp(PN11).5m5, corresponding to a percent disease index of 20.19% and 35.44% respectively, compared to 83.57% in control plants. Elevated activity of defense related enzymes (peroxidase, polyphenol oxidase, phenylalanine ammonia-lyase, catalase and superoxide dismutase) was recorded in plants treated with Tk × Tp(PN3)-1, Tp(PN11).5m5 and Ta × Tk-1. The relative expression of antagonism associated genes from different functional groups; chitinase, β-1,3-endoglucanase, subtilisin-like protease and terpene synthase were analyzed in both improved Trichoderma strains and their respective parental isolates using semi-quantitative RT-PCR. Expression levels were significantly upregulated in Tk × Tp(PN3)-1 and Tp(PN11).5m5 across all four genes compared to the parental isolates. This study identified three improved Trichoderma strains; Ta × Tk-1, Tk × Tp(PN3)-1 and Tp(PN11).5m5 that exhibited enhanced antagonistic potential, biochemical characteristics, plant growth promoting traits and defense enzyme activities, surpassing the reference strain T. asperellum. Therefore, following multi-locational field trials across different crops and comprehensive toxicological studies, these strains could be released as efficient biocontrol agents in the future.Item Process optimization and utilization of resistant starch from banana.(Department of Community Science ,College of Agriculture,Vellanikkara, 2025-09-11) Sruthy,P M; Sharon, C LBanana (Musa spp.), often hailed as the common man’s fruit, holds a special place in the scenario of agriculture and nutrition, besides having immense economic significance in India and across the globe. Banana, known for its year round availability, affordability, and rich nutrient profile, has transitioned from a commonly consumed fruit to a functional ingredient of growing interest in modern health and food industry. Resistant starch (RS) found in unripe green banana is a promising bioactive compound with potential health benefits. India is leading the global banana production, hence there lies untapped potential in harnessing banana starch, especially its resistant form, for the development of value added food products. However, native banana starch faces limitations in its functional properties, which can be effectively addressed through modification techniques such as Heat Moisture Treatment (HMT). This approach not only enhances the nutritional and functional quality of banana starch but also paves the way for its incorporation into a wide range of health oriented food formulations. Hence, the current study “Process optimisation and utilisation of resistant starch from banana”, was carried out with the objective of optimising the conditions for resistant starch formation in banana and its quality evaluation. The study also aimed to develop value added products incorporating various proportions of banana resistant starch. The popular GI (Geographical indication) granted Kerala banana variety Chengalikodannendran banana and the worldwide popular Cavendish variety Grand Nainebanana were selected for this study. Starch extracted from their flours yielded 26.89% (Chengalikodan) and 27.40% (Grand Naine), with purity of 88.62% and 89.73%, respectively. Resistant starch content was 20.02% in Chengalikodan and 20.62% in Grand Naine. Starch samples of Chengalikodan and Grand Naine banana were modified by autoclaving at 110℃ and 121℃ with different moisture content (10, 20, and 30 %) at three different time periods (15, 30 and 60 minutes). Resistant starch (RS) content in Chengalikodan banana starch was significantly affected by autoclaving conditions. Maximum RS (25.84%) was observed at 121°C for 30 minutes with 10% moisture. In Grand Naine starch, autoclaving enhanced RS from a control value of 20.62% to a peak of 30.52% (at 121°C for 30 minutes with 10% moisture). Repeated autoclaving and cooling cycles further increased RS in Chengalikodan, which reached 54.56% after four cycles, while Grand Naine peaked to 59.63%. Repeated autoclaving and cooling cycles were applied to the isolated banana starch. As a result of this treatment, RS3 was formed. The presence of RS3 confirms that the modification process was effective. The samples with maximum RS content from Chengalikodan and Grand Naine were selected for further analysis and product development. Two treated banana starch (RS3) samples (Chengalikodan and Grand Naine), along with corresponding flour and isolated starch, were initially analysed for colour index and granular morphology. Morphological analysis showed that flour and isolated starch granules varied in shape, size, and surface texture based on processing. Chengalikodan and Grand Naine flours had irregular, oval, and elongated particles with smooth to rough surfaces, while isolated starch granules were smooth and more uniform. Autoclaving altered native starch structure, forming compact, aggregated granules due to retrogradation, with resistant starch showing larger, fused clusters and rougher surfaces. Chengalikodan flour had higher lightness and whiteness, which decreased isolated starch and treated starch. In contrast, Grand Naine showed consistently lower lightness across all forms, reflecting the impact of processing and variety on visual traits. The physicochemical properties of flour, isolated starch, and autoclaved starch samples from Chengalikodan and Grand Naine banana were evaluated over three months. Autoclaved starch samples of both Chengalikodan and Grand Naine showed higher pH (5.36 and 5.34), moisture (7.08 and 7.02%), water holding capacity (4.91 and 5.00%), and gelatinisation temperature (77.02 and 75.67℃), but lower bulk density (0.48 and 0.51g/ml), swelling power (8.86 and 8.88%), solubility (3.65 and 3.58%), syneresis (27.41 and 28.22%), dispersibility(75.14 and 76.31%), and peak viscosity (487cp and 571cp), which are important properties for the formulation of functional, shelf stable and healthy food products. This study assessed the nutritional, functional, and glycemic characteristics of flour, isolated starch, and treated starch (RS) samples of Chengalikodan and Grand Naine banana. Treated starch had the lowest total soluble solids (2.56 and 2.41ºBrix), with lower total and reducing sugars. Treated starch showed the highest carbohydrate content (87.72 g and 87.33 g/100 g), highest slowly digestible starch (18.88% and 18.59%) and lowest rapidly digestible starch (24.56% and 22.53%) for Chengalikodan and Grand Naine, respectively. It also contained high amylose of 35.42% (Chengalikodan) and 38.92% (Grand Naine) and lower amylopectin. Treated starch showed the lowest in vitro starch digestibility of 44.56% and 40.65% and the lowest glycemic index of 37.56 and 36.65, slightly increasing after three months, for Chengalikodan and Grand Naine, respectively. Instant custard mixes were developed using 10-35% banana resistant starch, 5-35% corn flour, and other ingredients. Both Chengalikodan (T4) and Grand Naine (T10) banana based custard mix with 20% RS had the highest overall acceptability of 8.55 and 8.22 respectively. Control custard mix (T0) had the highest brightness (L* = 83.93) and whiteness (WI = 79.66), while T4 and T10 showed reduced lightness (81.90 and 77.74) and whiteness (77.32 and 74.12). Banana resistant starch mixes had lower initial swelling power, solubility, water absorption capacity, and dispersibility, which declined further during storage. Bulk density and moisture were higher and increased over time. Carbohydrate, protein, and fat contents were initially lower and gradually decreased. Starch content was lower in T4 and T10 (56.21% and 54.95%) than in the control (62.91%). Rapidly and slowly digestible starch were also lower in T4 (57.62% and 10.23%) and T10 (58.23% and 10.25%), while resistant starch was higher (32.15% in T4 and 31.52% in T10) compared to the control. In vitro starch digestibility was lower in T4 and T10 (41.28% and 42.40%) than in the control (62.70%). Vermicelli was formulated using 25-45% resistant starch from Chengalikodan and Grand Naine banana, combined with banana flour and whole wheat flour (30-70%). Vermicelli with 100% refined wheat flour served as control. Sensory evaluation showed that T3 (35% Chengalikodan resistant starch + 15% banana flour + 50% whole wheat flour) scored highest overall acceptability (8.28). Correspondingly, uppuma made from T3 vermicelli also received superior sensory scores, with overall acceptability of 8.42. Products with Grand Naine resistant starch (35% Grand Naine resistant starch + 15% banana flour + 50% whole wheat flour) had slightly lower scores (8.24 for vermicelli and 8.15 for uppuma than Chengalikodan based products, though both were well accepted. The study compared physicochemical, nutritional, and starch digestibility properties of vermicelli made with RS from Chengalikodan and Grand Naine banana to a refined wheat flour control. Banana RS vermicelli had lower lightness and whiteness, with higher moisture content (6.89% in Chengalikodan, 6.95% in Grand Naine) than the control (6.33%). It also had higher carbohydrate and energy content, while protein and fat decreased over storage. Rapidly digestible starch was lower in banana RS vermicelli (41.45% and 43.09%) than the control (84.42%), while slowly digestible starch and RS were higher. Glycemic index was also lower (46.23 in Chengalikodan, 45.55 in Grand Naine) compared to the control (76.23). Instant uppuma mixes were made using Chengalikodan and Grand Naine banana resistant starch vermicelli (35% RS + 15% banana flour + 50% whole wheat flour). Among treatments with varying water volumes, T3 (100g vermicelli with 300 ml water) received the highest sensory scores for both banana varieties. The mixes showed better stability over three months of storage. The production cost of banana flour was ₹ 33/100g (Chengalikodan) and ₹ 19/100g (Grand Naine), while isolated banana starch cost ₹ 34/100g and ₹ 20/100g, respectively. Treated starch production cost was ₹ 23/100g (Grand Naine) and ₹ 37/100g (Chengalikodan). Custard mixes made with banana RS cost ₹ 40/100g (Chengalikodan) and ₹ 36/100g (Grand Naine), while vermicelli and instant uppumamixes with Chengalikodan RS cost ₹ 42/100g and ₹ 54/100g, compared to ₹ 33/100g and ₹ 45/100g for Grand Naine. Banana starch is a promising functional ingredient that can contribute to the development of health enhancing food products. Heat moisture treatment enhances its functional and physicochemical properties, opening new opportunities for health focused applications. This research highlights banana starch as a sustainable, cost effective ingredient with transformative benefits, poised to meet the growing demand for nutritious, innovative food solutions and shape the future of the food industry.Item Valuing the Complementarity in Rice-Fish Integrated Farming: The Case of Pokkali Ecosystem(Department of Agricultural Economics, college of agriculture, Vellanikkara, 2025-08-26) SUMITHRA,S; Indiradevi,PIntegrated Farming Systems (IFS) are known for their mutually complementary relations. The coastal saline ecosystem along the Ernakulam, Alappuzha and Thrissur districts of Kerala, referred to as Pokkali lands, follow the traditional practice of integrating paddy and fish/prawn farming. Despite the ecological resilience and economic viability, IFS in Pokkali ecosystem has experienced a significant decline in recent decades, shifting to monoculture practices of aquaculture. In this background, the study was conducted with the main objectives of understanding the dynamics of rice-fish rotational system and assessing the relative economics, estimating the economic value of complementarity between the systems based on empirical analysis, estimating the value based on stakeholder knowledge, and effecting the comparison between the two estimates. The study was conducted in Ernakulam district, which holds the largest share (64%) of Pokkali lands focussing on five prevalent farming systems: Rice–Prawn IFS, Rice–Fish IFS, Prawn monoculture, Fish monoculture, and fallowing. Multistage sampling method, was adopted with district, block panchayat (BP) and grama panchayat (GP) as the respective stages of selection. The BP and GP with highest area under respective farming practice were purposively selected, while the sample respondents were chosen on random basis. The total sample size was 250 farmers (random sample of 50 from each system) and 120 other stakeholders, which include officers of agriculture department as well as fisheries department, farm labourers, and general public, working/residing in the locality. Data was gathered from the respondents through personal interview method employing structured pre-tested interview schedule. Soil samples were also collected from the selected farms following IFS system, before and after the rice crop and were analysed in soil testing laboratory under KAU. Analytical tools employed include partial budgeting to assess the relative economics of various systems, productivity change method for capturing the positive externality due to complementarity in IFS, and contingent valuation method. The Pokkali ecosystem in Kerala, a unique agro-ecological unit, has witnessed significant decline over the past two decades. Though official data is not published, informal reports show Pokkali paddy cultivation area shrinking from about 25,000 hectares in the 1980s to merely 5,707 hectares by 2021, driven by low rice profitability, rising wages, labour scarcity, and large-scale land conversion for non-agricultural use. Remote sensing studies further underscore the impact of urbanization and infrastructure growth in altering land use patterns, along with a significant shift toward monoculture aquaculture, threatening the sustainability of this ecologically sensitive system. The Rice–Aquaculture IFS in Pokkali operates in a seasonal rotation: rice is cultivated from June to October, followed by prawn or fish farming from November to April. Despite receiving policy and legal support for rice component, subsidies and mandatory rice cultivation certificates for aquaculture licensing, the system faces declining trend. Rice cultivation yields 1,326 kg/ha, with negative net returns of ₹40,383/ha, it remains financially unviable without support. Conversely, prawn farming is capital intensive (₹2,01,889/ha) but highly profitable, yielding returns of ₹4,88,373/ha and net profit of ₹2,86,484/ha. Together, the rice–prawn IFS yields a total return of ₹5,57,325/ha with a net return of ₹2,46,101/ha and a favourable benefit-cost ratio (BCR) of 1.79. On the other hand, the rice–fish IFS, offers limited economic benefits with relatively low fish yield and losses from rice cultivation, this system yields only ₹10,028/ha in net returns and a marginal BCR of 1.03. Comparative analysis indicates prawn monoculture which is resource-intensive and environmentally less sustainable, generates lower net returns (₹1,68,338/ha) and a reduced BCR (1.60) compared to integrated systems, primarily due to higher operational expenses especially feed costs. Monoculture practice, particularly fish farming, delivers higher net returns (₹3,97,311/ha) and a BCR of 2.32 outperforming the rice–fish IFS, incentivizing farmers to abandon traditional IFS practices. The higher profitability in monoculture is primarily due to the ability to rear more number of fish species, including long-duration and high-value species. Such practices are not feasible in the rice-fish IFS, where aquaculture is typically restricted to six-months. However, partial budgeting reveals that shifting from monoculture to integrated farming results in net economic gains, particularly in the rice–prawn system, which offers an additional gain of ₹69,837/ha, despite higher cultivation costs. This gain stems from reduced input expenses in aquaculture (artificial feed, eradicants, electricity) and dual income sources. In monoculture systems, only aquatic species typically high-value prawns like Tiger prawns or commercially viable fishes are cultivated by skipping Pokkali rice cultivation. The relatively poor economic gains along with cultivation challenges act as major drivers for shifting from IFS to monoculture practices, which are very fast and visible in certain pockets like Kumbalam, Kumbalanghi, Chellanam panchayats. At the same time, the ecological complementarity in IFS, particularly the effect of improved soil quality, is also significant. Statistical analysis shows that a 1% increase in Soil Quality Index (SQI) leads to a 0.25% rise in rice yield, which is equivalent to 3.23 kg/ha or ₹167.96/ha. When scaled across 5,000 ha, the realized value of this yield benefit is ₹8.40 lakh. Empirical studies (Sreelatha and Joseph, 2019) confirm that IFS improves SQI by 41.6% over monoculture, equating to a benefit of ₹3.49 crore ecosystem-wide. The study underscores that IFS is both economically viable and ecologically beneficial, especially when complemented with improved management and varietal selection. High-yielding Pokkali varieties provide 29.14% higher yields than traditional types. Yet, current subsidy policies fail to incentivize full-cycle crop management, often resulting in low yield realization and misuse of support mechanisms. Additionally, perceived rice yield gains, though lower than realized, still affirm this ecological value, estimated at ₹97.76/ha. The undervaluation of soil quality benefits among stakeholders reveals a critical perception gap, particularly among aquaculture farmers and fisheries officials, who tend to favour short-term economic returns from monoculture over long-term ecological gains. Stakeholder perceptions reveal wide variation. While agricultural officers’ express optimism about IFS yield potential, fisheries officials lean toward aquaculture. Farm labourers report higher perceived yields, reflecting their hands-on experience. Farmers practicing monoculture acknowledge the ecological benefits of IFS but cited labour shortages, profitability concerns, and climatic risks as key barriers. The study recommends scientific mapping of Pokkali areas using remote sensing, developing a database of Pokkali landholders, linking subsidy to yield or performance metrics to ensure proper crop management, applying externality gains in extension methods, strengthen compliance mechanisms to ensure rice cultivation precedes aquaculture licensing, reinforcing the Pokkali Land Development Authority and establishing targeted support programs to address region-specific socio-economic barriers, and considering the scope of introducing a targeted Green Granary Support Scheme for Pokkali farmers that provides financial incentives, technical support, and market linkages to promote eco-friendly farming practices. Further research focus is to be on assessing the role of water quality in influencing prawn/fish yield across IFS and monoculture systems, examining the efficacy of current subsidy schemes, conducting longitudinal studies on soil health, salinity, and system resilience. IFS being an effective system that ensures food security, profitability and sustainability, is considered as a powerful tool for enhancing the economic status of small and marginal farmers. There should be programme to conserve and support the traditional rice-fish IFS models, especially in view of the climate change challenges.Item Baseline susceptibility of rice leaf folder Cnaphalocrocis medinalis (Guenee) (Lepidoptera: Crambidae) to selected insecticides(Department of Agricultural Entomology, College of Agriculture, Vellanikkara, 2025-08-29) Seena R Subhagan; Berin PathroseWith the rising food production demands, pesticides remain essential for achieving high yields, particularly in staple crops like rice. Despite the known environmental hazards of chemical pesticides, their repeated use has become common practice, often leading to selection pressure and the development of insecticide resistance. This issue is exacerbated when insect pests like the rice leaffolder, Cnaphalocrocis medinalis, which undergoes several generations a year, are exposed to the same insecticide across consecutive generations. Recent failures in controlling rice leaffolder outbreaks in Kerala have raised concerns, though no formal studies have documented insecticide resistance in these populations. This study aimed to address this gap by assessing the susceptibility of rice leaffolder populations to selected insecticides and investigating potential resistance mechanisms. Field populations from five agroecological units (AEUs) in Kerala were assessed for insecticide resistance through laboratory bioassays, with WYD (AEU 20) as a susceptible reference. The PKD (AEU 23), KUD (AEU 4), and TCR (AEU 6) populations experienced significant selection pressure, leading to moderate to high resistance to the tested insecticides, surpassing the resistance observed in the ONT (AEU 3) population. Resistance to acephate (5.07- to 172.53-fold) was identified for the first time in India. High resistance to quinalphos (133.24- to 611.37-fold) and carbosulfan (25.40- to 347.96-fold) were also noted. The observed carbosulfan resistance, despite no prior use, likely stems from cross-resistance due to previous organophosphate exposure, as both target acetylcholinesterase. Continuous exposure intensified resistance to lambda-cyhalothrin (up to 763.66-fold) and fipronil (up to 154.83-fold). Diamide resistance was significant, with chlorantraniliprole (1089.63 fold) and flubendiamide (1572.64-fold), marking the first reported flubendiamide resistance in C. medinalis in India. Cross-resistance to cartap (14.85- to 23.90-fold) and emamectin benzoate (24.97- to 81.09-fold) suggested resistance mechanisms driven by non-specific detoxification pathways. Further, the study aimed to elucidate the biochemical mechanisms of resistance by assessing the activities of detoxification enzymes. Resistant populations exhibited significantly elevated activities of carboxylesterase (CarE) (1.1–1.6-fold), cytochrome P450-dependent monooxygenase CytP450) (1.5–2.5-fold), and glutathione S transferase (GST) (2.3–3.0-fold). These findings underscore the increased activity of detoxifying enzymes as a contributing factor to the resistance observed in C. medinalis further confirmed through synergism bioassays. Bioassays with synergists revealed diverse resistance mechanisms across populations, driven by variations in detoxification enzyme activity. Metabolic resistance to acephate, quinalphos, carbosulfan, and lambda-cyhalothrin was primarily associated with CarE, CytP450, and GST, either individually or in combination. Multiple enzyme involvement was evident in PKD, KUD, and TCR, while CytP450 had a dominant role in ONT, highlighting enzyme-specific contributions to insecticide resistance. However, metabolic detoxification was not the primary driver of chlorantraniliprole and flubendiamide resistance in most populations, suggesting the involvement of alternative mechanisms. Minor contributions from CarE and CytP450 were detected in PKD, while slight synergistic effects in KUD may be linked to endosymbiont mediated resistance. In the case of fipronil, resistance was mediated by CytP450 in PKD, KUD, and ONT, whereas non-metabolic mechanisms likely contributed to the high fipronil resistance observed in TCR. These findings underscore the complexity of resistance mechanisms and highlight the need for further investigation into alternative pathways for diamide and fipronil resistance. This study investigated target site insensitivity as a potential resistance mechanism to diamides and fipronil in C. medinalis by analyzing mutations in the ryanodine receptor (RyR) and resistance to dieldrin (Rdl) genes. Gene duplication and a novel I4712N mutation in transmembrane (TM) domain 3 of RyR were detected in ONT and KUD populations, while PKD and TCR populations had a nonsynonymous mutation (F4691L) and a nonsense mutation (Y4692*) in the TM2-TM3 linker of the RyR gene, which may impact diamide binding. Additionally, a K4885K synonymous mutation was identified in TCR in the TM4-5 linker. As these mutations are newly reported, functional validation is required to confirm their role in resistance. Molecular analysis of the Rdl gene identified an A282S mutation in TM 2 of all populations, including the susceptible WYD, suggesting a limited role in fipronil resistance. Notably, this study reports a novel V457F mutation in TM 4 of the Rdl gene in the resistant TCR population, which may have contributed to high fipronil resistance (154.83-fold) by altering GABA receptor function. The absence of target-site mutations for isoxazoline and meta-diamides suggests their continued efficacy against C. medinalis. Metagenome analysis identified Pantoea sp. and Wolbachia sp. as potential endosymbiont contributors to microbial detoxification of chlorantraniliprole and flubendiamide resistance in KUD. These findings provide new insights into resistance mechanisms and highlight the need for further functional confirmation. Rice leaffolder populations in Kerala have developed diverse resistance mechanisms in response to sustained insecticide pressure, exhibiting metabolic and target-site adaptations. This study presents the first detailed evaluation of insecticide resistance in C. medinalis from Kerala, uncovering alarming resistance levels to multiple insecticides, including newly documented cases for acephate, carbosulfan, lambda-cyhalothrin, and flubendiamide. Metabolic detoxification, primarily through CarE, CytP450, and GST, played a key role in resistance against organophosphates, carbamates, and synthetic pyrethroids, with multiple detoxification pathways raising concerns about cross-resistance. Mutations in the RyR and Rdl genes suggest target site insensitivity for diamides and fipronil (TCR), while the potential involvement of endosymbionts in microbial detoxification (KUD) adds another layer of complexity. These findings highlight the urgent need for proactive resistance management strategies, integrating insecticide rotation, biological control, and molecular monitoring to sustain effective pest management in Kerala’s rice ecosystems.Item Structural and functional dynamics of NICRA villages in Kerala and Karnataka:stakeholder analysis(Department of Agricultural Extension,College of Agriculture,Vellayani, 2025-07-16) Manju Prem,S; Jayalekshmi,GThe present research, titled "Structural and Functional Dynamics of NICRA Villages in Kerala and Karnataka: Stakeholder Analysis," explores how socio economic characteristics, agro-ecological conditions, and stakeholder roles contribute to climate resilience in agriculture. The study was conducted across four NICRA villages, representing distinct climatic challenges: two drought-affected villages in Karnataka (Hanumaigarahalli in Chikkaballapur and Durgadanagenahalli in Tumkur), one drought-affected village (Pattithara in Palakkad), and one flood-affected village (Edathua in Alappuzha) in Kerala. A total of 300 respondents participated, including 160 farmers, 40 KVK (Krishi Vigyan Kendra) officials, and 100 other stakeholders, including researchers, line department officials, local government representatives, and NGOs. The study employed a mixed-method approach, combining quantitative and qualitative tools to collect and analyse data on stakeholders' perceptions of climate change, vulnerability, capacity needs, and training preferences. The dependent variable of the study is the perception of capacity needs under NICRA. Perception scales were developed and validated for both farmers and KVK officials to assess their capacity needs under the NICRA program. Thirteen independent variables for farmers and six for KVK officials were selected. Statistical tools used included frequency and percentage analysis, mean, standard deviation, Z-test, one way ANOVA, correlation analysis and multiple regression analysis. The majority of farmers (45%) perceived their capacity needs as upper medium, followed by 23.75 per cent perceiving them as lower medium, and 16.25 per cent as low. KVK officials, on the other hand, predominantly perceived their capacity needs as lower medium (57.5%), with only a small proportion perceiving them as high (12.5%). These scales were correlated with objective measures such as operational landholding and service experience, further validating the perception results. Key findings revealed that farmers, especially smallholders, were identified as the most important stakeholders in the NICRA project, followed by women farmers and KVK officials. Local self-government bodies, such as Panchayats and Gram Sabhas, also played a critical role, while NGOs and community-based organizations (CBOs) were found to be less influential in project execution. This shows there is a need to prioritize engagement with the most important stakeholders for effective implementation of climate resilience initiatives. The study also examined the socio-economic characteristics of the farmer respondents. The majority (81.25%) of respondents were male, with education levels ranging from illiterate to high school, and most managed marginal to small landholdings. The majority of respondents were relatively inexperienced in farming, with a significant portion of farmers falling into the novice or advanced beginner categories. Income levels were predominantly low to middle, indicating significant economic challenges. The frequency of contact with extension agencies, especially KVK, was found to be high, and participation in capacity-building activities varied, with crop management and integrated farming systems being the most popular topics. Farmers' preferences and adoption of climate-resilient practices were also examined. High Yielding Varieties, Soil Conservation, and Custom Hiring Centres were the most preferred practices, with High Yielding Varieties ranking highest in adoption. Farmers reported significant benefits from these practices, including increased income, reduced climate risks, and enhanced crop production. However, farmers emphasized the need for continued government support, lower initial investment costs, and sustained assistance from the NICRA project to enhance the uptake of these practices. The study found that farmers in both Kerala and Karnataka perceived significant climate changes, particularly rising temperatures. In Kerala, 93.75 per cent of farmers and in Karnataka, 90 per cent of farmers noted an increase in temperature. Precipitation patterns also varied significantly between the two states, with 45 per cent of farmers in Kerala observing a decrease in rainfall and 93.75 per cent of farmers in Karnataka reporting reduced rainfall, indicating more severe drought conditions in the latter state. Both states reported concerns about delayed monsoon onset, with 98.75 per cent of Karnataka farmers and 56.25 per cent of Kerala farmers noting this shift, which disrupts planting schedules. Also, a significant reduction in the frequency and intensity of rainfall was reported across both regions, emphasizing the growing climate challenges farmers are facing. The study also examined the farming practices most vulnerable to climate stresses. In Kerala, crop production was found to be the most vulnerable due to dependence on monsoon rains, followed by pisciculture and horticulture, which are affected by water scarcity and temperature fluctuations. In Karnataka, horticulture was identified as the most vulnerable practice, followed by pisciculture and crop production. Poultry and livestock farming showed moderate vulnerability, while floriculture and beekeeping were less impacted by climate stress. These findings highlight the need for targeted interventions in these sectors to reduce vulnerability. Farmers' preferences regarding NICRA training were also analysed. The most preferred training agency was KVK, followed by universities and private seed/fertilizer companies. Demonstration was the preferred training method, emphasizing the importance of practical, hands-on learning. Farmers preferred training durations of 3-6 days, ideally conducted before the cropping season to ensure preparedness. Monthly training was also favoured, with pest and disease management being the top priority for both knowledge and skill development. The study also highlighted the strengths and gaps in the capacity development of farmers. Teamwork, norms, and network building were identified as strong social capacities, while gaps were observed in group process skills, shared vision, and strategic planning. Among individual capacities, leadership and entrepreneurship showed promise, but weaknesses were evident in technology adoption and financial literacy. Targeted training in these areas is needed to equip farmers to navigate challenges and adopt climate-resilient agricultural practices effectively. Key constraints faced by farmers in relation to NICRA training were also identified. The most significant constraint was the inadequate assessment of training needs, which led to a mismatch between training content and farmers' practical requirements. Other constraints included lack of storage facilities for perishable produce, absence of follow-up actions for clarification, and lack of participatory planning. Addressing these gaps in training delivery and logistical support could significantly enhance the effectiveness of the NICRA program. The study further examined the profiles of KVK officials, revealing diverse characteristics in terms of age, education, and service experience. Most officials had postgraduate or PhD qualifications, with a mix of experienced and novice respondents. NICRA-specific experience was limited, with most officials being novices or moderately experienced in the program. Training participation was varied, with some officials having attended advanced or intensive training. These findings emphasize the need for further capacity-building efforts to strengthen the expertise of officials, especially in NICRA-specific activities. The study's relational analysis revealed that service experience and NICRA-specific experience significantly influenced officials' perceptions of the program. Age, education, and training participation showed weaker correlations. These findings underlines the importance of experience in shaping officials' perceptions and highlight the potential for targeted training to improve the implementation of the NICRA program. A framework named “NICRA Capacity Development and Implementation Framework” (NCDIF) was developed for the study, designed to enhance climate resilience among stakeholders. Phase 1 involves needs assessment, stakeholder analysis, baseline data collection, and resource mapping. Phase 2 focuses on capacity building through customized training programs, workshops on financial literacy, and access to resilient crop varieties. Phase 3 emphasizes implementation, improving resource accessibility, networking, and forming farmer cooperatives. Phase 4 includes monitoring, evaluation, and feedback to assess success and adjust strategies. The framework covers short-term (0-6 months), medium-term (6-12 months), and long-term (18-36 months) goals. To address constraints in the NICRA program, strategies for farmers include participatory training needs assessments, cold storage units, structured follow-ups, participatory planning, crop insurance awareness, pre-training surveys, monitoring frameworks, vocational training, improved credit access, and gender-sensitive programs for women. For officials, strategies focus on mechanization subsidies, participatory planning, enhanced communication skills, transparent trainee selection, timely input availability, and hands-on training. Also, real-time service monitoring and performance-based incentives for extension staff are recommended. These strategies aim to enhance farmer engagement, training relevance, and program delivery. This research emphasizes the vital role of stakeholders in boosting climate resilience in agriculture. The findings stress the importance of a targeted, inclusive approach to engaging farmers, KVK officials, and other stakeholders in capacity building initiatives. Addressing constraints, refining training assessments, and enhancing both individual and social capacities are essential for the success of climate resilient agricultural practices within the NICRA program. By focusing on these areas, stakeholders can collaborate to mitigate climate change impacts and strengthen the resilience of farming communities in Kerala and Karnataka.Item Nucleopolyhedrovirus mediated biointensive management of polyphagous pest Spodoptera litura F.(Department of Agricultural Entomology,College of Agriculture,Vellayani, 2025-09-12) Binseena,S R; Faizal,M HThe study entitled ‘Nucleopolyhedrovirus mediated biointensive management of polyphagous pest Spodoptera litura F. was carried out at the Department of Entomology, College of Agriculture, Vellayani, during 2019-2024 with the objective of development and evaluation of liquid and bait formulations of Spodoptera litura nucleopolyhedrovirus (SlNPV) incorporating botanicals and identification of viral gene sequences (iap and egt) of pesticidal relevance in SlNPV genome. Bioassay of botanical oils such as neem, pongam, and cashew nut shell liquid (CNSL) was done against S. litura under laboratory conditions. Cent percentage mortality of larvae was observed for neem oil 4 % and pongam oil 10 % treatments at 144 HAT and CNSL 5 % at 168 HAT. The LT50 values of the botanical oils were computed to 142.45, 146.37, and 176.54 hours for neem oil 4 %, pongam oil 10 %, and CNSL 3 % respectively with corresponding LT90 values of 329.04, 625.90, and 357.84 hours. In the bioassay of SlNPV, 100 % mortality was caused by the treatments with 1010 and 109 POB mL-1 which was at par with the mortality caused by lower concentrations of 108 and 107 POB mL-1 at 192 HAT. The effective doses (ED) of neem oil, pongam oil and CNSL were arrived at as 3.4 %, 4 %, and 2.5 % respectively by critically assessing the three important parameters of mortality, LC50 value and leaf area damage. A combination treatment of SlNPV (107 POB mL-1) and different doses (ED, ¾ ED, ½ ED, and ¼ ED) of botanical oils was attempted with the aim of reducing the lethal time of SlNPV. Significantly high mortality of S. litura (53.33 %) could be achieved in the combination treatments of SlNPV + neem oil 2.5 % as early as 48 HAT. However, at 144 HAT both SlNPV + neem oil 2.5 % and SlNPV + pongam oil 3 % treatments could result in 93.33 % mortality as against 60 % for treatment with SlNPV alone. The development of emulsifiable suspension (ES) formulations of SlNPV was attempted employing different oils as base. Isopropanol was identified as the solvent since it could solubilize all the oils tried at 5 % concentration, with low turbidity and viscosity. Emulsifier combinations of Span 20 + Triton X -100 (29:71) at 5 % for neem oil, sunflower oil, coconut oil, mustard oil, as well as Span 20 + Tween 80 (47:53) at 12 % for pongam oil, all yielding HLB value of 12 produced excellent bloom of Score 5 upon emulsification. SlNPV was dispensed into the oil-solvent-emulsifier combination so as to yield a final concentration of 1010 POBs mL-1. Among the five ES formulations evaluated, neem oil based (ES1) and pongam oil based (ES2) formulations were found to be superior producing significantly high mortality of 100 % and 93.33 % respectively even after 7 months of storage. Boric acid 1 % was selected and added to the formulation since it yielded superior protection of SlNPV with OAR (original activity remaining) value of 65.72 % upon exposure to sunlight. Development of storable ready to use bait formulations containing SlNPV and botanical oils were attempted, utilizing selected combination base matrices containing any two of wheat bran (WB), wheat flour (WF), rice bran (RB), and chickpea flour (CF) along with additives (A) (jaggery, cornstarch, CMC) as well as artificial diet alone. Based on the feeding preference and bait consumption by S. litura in free-choice and no-choice situations respectively three base matrices viz., artificial diet, WF (75 %) + CF (25 %) and WB (65 %) + WF (35 %) + A were selected, into which SlNPV (107 POB g-1) and either neem oil (2.5 %) or pongam oil (3 %) were infused. All three baits thus developed exhibited satisfactory structural integrity upon dehydration and rehydration. WB + WF based two bait formulations B3 and B2 of SlNPV containing pongam oil and neem oil respectively, were found to produce significantly high mortality of S. litura (100 % and 93.33 % respectively). Superior emulsifiable suspension and bait formulations alone and in combinations of the ones having the same botanical oil were evaluated for the management of S. litura in okra under polyhouse conditions. Combined application of an emulsion of ES2 and bait formulation B3 containing both SlNPV and pongam oil produced 96.67 % mortality of S. litura at 7 DAT, an effect on par with the chemical insecticide Flubendiamide 39.35 % SC. Identification of viral genes iap and egt, of pesticidal relevance was attempted in SlNPV for which specific primers with oligonucleotide sequences forward 5' GATTCGATCGCTGTCAACCT-3' reverse 5'-TTTCACTTTGGATGCTGCCT-3' and forward 5'-ATGGACTCGAACATGTTGGAC-3' reverse 5' AAGTCGAACATTGCGTATTTGG-3' respectively were constructed. Amplicons of size 500 bp and 600 bp could be detected in PCR with these primers, indicating the presence of both iap and egt sequences in SlNPV. The combined application of emulsifiable formulation ES2 [containing SlNPV (1010 POB mL-1), pongam oil (82 %), isopropyl alcohol (5 %), Span 20 + Tween 80 in the ratio 47:53 (12 %) and boric acid (1 %)] and bait formulation B3 [containing SlNPV (107 POB g-1 ), pongam oil (3 %), base matrix of WB + WF in the ratio 65:35 (77 %), jaggery (19 %), corn starch (0.3 %) and CMC (0.7 %)], developed in the present study each delivering SlNPV and pongam oil @ 107 POB mL-1/g-1 and 3 % respectively upon application was found effective in managing S. litura and have the potential to be developed as the predominant eco-friendly tactic in its IPM.Item Acaricide resistance in spider mites (Acari: Tetranychidae) Infesting major crops of Central Kerala(Agricultural Entomology, College of Agriculture, Vellanikkara,, 2025-08-18) Penuballi Swathi; Haseena BhaskarSpider mites (Acari) inhabit a wide array of environments and pose significant threat to a variety of commercially grown vegetable crops and ornamental plants. Chemical management measures using synthetic acaricides remains the primary means of mite management, globally. However, the repeated use of chemical pesticides has led to the development of resistance in mite populations, including resistance to acaricides with novel modes of action, resulting in control failures. TetranychustruncatusEhara and Tetranychusgloveri Banks are the predominant spider mite pests on vegetable crops and ornamental plants in Kerala. Mite management in vegetable fields and horticultural nurseries of Kerala primarily relies on synthetic acaricides like spiromesifen, fenazaquin and diafenthiuron. Increased instances of control failures, despite the application of recommended doses of these acaricides, have recently been reported by the farmers and nursery owners. Sole dependence on acaricides for a prolonged period might have resulted in the reduced susceptibility of mite populations to commonly used acaricides. Hence, a study was carried out to investigate the susceptibility of the field populations of T. truncatus and T. gloveri to commonly used acaricides, the possible development of cross /multiple resistance and to elucidate the underlying mechanisms of resistance. Purposive sampling surveys were conducted across commercial horticultural nurseries, vegetable fields and tissue culture (TC) hardening units in central Kerala (Thrissur, Ernakulam, Palakkad and Malappuram) to collect spider mite populations. Isoline cultures of eight T. truncatus populations collected on marigold (Mg1Tr) and vegetable crops (Cp1Pt, Cu1Pt, Ok1Pt, Am2Pt, Am3Vt, Cp2Tv and Am4Tv), and nine T. gloveri populations collected on adenium (Ad1Rg and Ad2Sd), gerbera (Gr1Pt), dahlia (Da1Vt), anthurium (An1Bv) and tissue culture banana (Bn3Tr, Bn2Kn, Bn1Gn and Bn4Ak) were maintained in the laboratory with unique accession numbers. The laboratory maintained populations of T. truncatus (SST) for more than 10 years (>300 generations) and T. gloveri (SSO) for more than six years (>180 generations), without exposure to acaricides were designated as susceptible reference populations. The laboratory bioassay of T. truncatus with fenazaquin showed moderate levels of resistance in the populations on amaranthus (Am2Tr- 39.70 folds) and marigold (Mg1Tr- 25.60 folds) populations from Thrissur, cucumber from Pattambi (Cu1Pt- 12.90 folds) and amaranthus from Vyttila (Am3Vt- 10.50 folds). The other populations collected on amaranthus from Tavanur (Am4Tv) and on okra (Ok1Pt), and cowpea (Cp1Pt) from Pattambi, recorded low levels of resistance (RR 3.70- 7.90 folds). Among the T. gloveri populations, adenium population from National Rose Garden, Thrissur (Ad1Rg- 57.20 folds) and TC banana population from Kannara (Bn2Kn- 41.04 folds) recorded high levels of resistance to fenazaquin, while the mite populations collected on TC banana plants from Vyttila (Bn1Gn- 15.72 folds) and Thrissur (Bn3Tr- 15.80 folds), and on dahlia from Vyttila (Da1Vt- 13.31 folds) recorded moderate level of resistance. Other T. gloveri populations collected on gerbera, anthurium and adenium showed only low levels of resistance. Tetranychustruncatus collected on marigold (81.90 folds) and amaranthus (79.75 folds) from Thrissur recorded very high levels of spiromesifen resistance. The amaranthus population from Vyttila (Am3Vt- 33.41 folds); cowpea (Cp1Pt-25.16 folds) and okra (Ok1Pt- 25.83 folds) populations from Pattambi, showed moderate levels of resistance, while populations on cowpea (RR 07.08) and amaranthus (RR 05.90) collected from Tavanur recorded low levels of resistance. Susceptibility studies of T. gloveri with spiromesifen showed that the population on adenium from National Rose Garden (76.33 folds) and on TC banana from Kannara (71.33 folds) exhibited high levels of resistance. Populations collected on TC banana from Vyttila (30.33 folds), Thrissur (28.17 folds) and Anakkayam (13.79 folds) recorded moderate levels of resistance. The populations collected on the ornamental plants viz., dahlia (24.33 folds), anthurium (19.08 folds) and adenium (17.25 folds) also recorded moderate levels of resistance to spiromesifen. Low to moderate levels of resistance to diafenthiuron were recorded in T. truncatus (1.94- 17.56 folds) and T. gloveri (1.95- 15.57 folds), where marigold population from Thrissur (17.56 folds) and adenium population from National Rose Garden (15.57 folds) recorded significantly higher levels of resistance, respectively. Tetranychustruncatus and T. gloveri populations with resistance to fenpyroximate showed moderate levels of cross-resistance to fenazaquin and the propargite resistant populations showed cross resistance to diafenthiuron. However, the field populations recorded only low levels of multiple resistance to chlorfenapyr and hexythiazox (acaricides with different modes of action) in T. truncatus (1.20- 5.40 folds; 1.00- 1.50 folds) and T. gloveri (1.10- 2.35 folds; 2.08- 12.00 folds). Assay of detoxification enzymes in T. truncatus and T. gloveri showed significantly elevated activities of carboxylesterase (CarE) (1.27-2.27fold; 1.59-2.10 folds), cytochrome P450 monooxygenase (CytP450) (1.36- 4.98 folds; 1.08-3.10 folds), and glutathione S-transferase (GST) (1.00- 2.12 folds; 1.09- 1.98 folds) in resistant populations. The highest activity of detoxifying enzyme was recorded in T. truncatus population on marigold for CytP450. The study on differential gene expression and sequence variation of the CYP392E10 gene (encodes CytP450 enzyme) in the spiromesifen and fenazaquin resistant marigold population of T. truncatus showed a lower CT value with 7.61 folds higher gene expression than the susceptible population. Sequence analysis of CYP392E10 gene in the resistant population showed four single nucleotide polymorphisms (SNPs), where T is substituted by A (256th, 676th and 1356th) and A is replaced with G (708th position). The alignment of amino acid sequences of the susceptible and resistant T. truncatus populations showed substitution of Lleucine with methionine at 86th position and phenylalanine with isoleucine and lysine at 226th and 452nd positions, respectively. This study reports alarming levels of acaricide resistance in the spider mites, T. truncatus and T. gloveri in central Kerala, to commonly used acaricides. The mite species were also found to have developed significant levels of cross resistance to many unexposed acaricides. However, significantly low level of multiple resistance to the acaricides, chlorfenapyr and hexythiazox suggests their suitability as alternatives to commonly used acaricides in mite management. The study highlights the role of detoxifying enzymes and the overexpression of the related gene, particularly CytP450 in the development of resistance against commonly used acaricides (fenazaquin, spiromesifen and diafenthiuron). The study also provides new insights into the resistance mechanisms in the mite species in response to sustained acaricide pressure, exhibiting metabolic and target-site insensitivity, which further needs functional validation.Item Production technology for augmenting yield and quality of mangosteen (Garcinia mangostana L.)(Department of Fruit Science, College of Agriculture, Vellanikkara, 2025-07-17) Rajendra, B N.; Jyothi BhaskarMangosteen (Garcinia mangostana L.), known as the ‘Queen of Tropical Fruits’ is a parthenocarpic, evergreen fruit tree which is native to the Malay Archipelago. Fruits are valued for its exquisite luscious and delicious snow-white arils. It has numerous health benefits due to its rich content of glucose, vitamins (A, B, and B2), minerals (Ca, P, and Fe), fibre, tannins, xanthones, and antioxidants. The major cultivated countries are Indonesia, Thailand, Philippines, Malaysia, Cambodia, Vietnam, Myanmar, Sri Lanka, India and China. In India, commercial cultivation is restricted to southern states particularly Kerala with warm, humid climate, followed by Tamil Nadu and some parts of Karnataka. The fruits are highly priced domestically and globally. Farmers engaged in mangosteen cultivation are facing a lot of problems, mainly, low availability of seeds, poor seed viability, low germination percentage, and sluggish growth of seedlings. Additionally, they are also facing constraints such as lack of quality planting materials, protocol for microbial inoculation, proper nutrient management practices, usage of bio-stimulants and so on. To address these issues, this research project on “Production technology for augmenting yield and quality of mangosteen (Garcinia mangostana L.)” was undertaken with the objective of fostering seedling growth and enhancing the quality yield of mangosteen by adopting balanced nutrition practice. The study was conducted at Department of Fruit Science, College of Agriculture, Vellanikkara, Kerala Agricultural University, Thrissur, and at a farmer’s field in Pariyaram village near Chalakudy town in Thrissur district, Kerala, during September 2022 to August 2024. In the first experiment on ‘Microbial consortium seed treatment for improving germination attributes of mangosteen’ the results were found to be non-significant, however, the seeds treated with microbial consortium (100 g/kg of seeds) took only minimum number of days for germination with increase in germination percentage compared to the control. Microbial consortium seed treatments showed its effect at later stages of growth at 30 and 45 days, as compared to 15 days after germination. Among the treatments, the treatments T3 (PGPR Mix-1 + Piriformospora indica) and T4 {Arka Microbial Consortia (AMC)} were comparable. At 45 days after germination, treatments T3 and T4 recorded notable results regarding seedling height (6.34 & 5.80 cm), number of leaves (3.71 & 3.49), length of leaves (5.62 & 5.16 cm), breadth of leaves (2.79 & 2.56 cm), total leaf area (42.21 & 32.54 cm2), chlorophyll-a (0.749 & 0.715 mg/g), chlorophyll-b (0.712 & 0.706 mg/g), total chlorophyll (1.460 & 1.421 mg/g), in addition to length of roots (6.19 & 5.76 cm), girth of roots (1.90 & 1.81 mm), number of secondary roots (12.00 & 10.50), seedling fresh weight (3.33 & 2.74 g), and seedling dry weight (644.75 & 546.00 mg). This result might be due the better nutrient availability facilitated by the microbial consortium through atmospheric nitrogen fixation, mineral nutrient solubilization, mobilization, and presence of phytohormones, which in turn enhanced the efficiency of photosynthesis and seedling development and their characteristics. The study thus recommends the incorporation of PGPR Mix-1 + Piriformospora indica (T3) or Arka Microbial Consortia (AMC) (T4) into the seed treatment protocol to improve germination and to accelerate growth performance of mangosteen seedlings. The impact of microbial consortiums in combination with foliar application of NPK @ 3:1:1 ratio, on the growth and development of mangosteen seedlings were assessed over an eight-month period in the second experiment ‘Triggering seedling growth in mangosteen using microbial consortium and by foliar nutrition’ wherein the observations were recorded at two-months interval. After eighth month, two treatments, namely treatment T5 (PGPR MIX-1 (10 g/plant) + AMF-Glomus fasciculatum (5 g/plant) + foliar spray NPK (3:1:1) at 0.5 %) and T6 {Arka Microbial Consortia (20 g/plant)} recorded significant values regarding growth metrics such as stem diameter (3.60 & 3.34mm), number of leaves (13.13 & 12.03) and breadth of leaves (2.87 & 2.75 cm); biochemical traits including total chlorophyll (1.330 & 1.293 mg/g) and carotenoid (0.301 and 0.283 mg/g); biomass accumulation such as seedling fresh weight (11.02 & 9.43 g) and seedling dry weight (3.30 & 2.81 g); root characters including root length (20.70 & 19.70 cm) and number of secondary roots (19.33 & 17.33). The highest seedling survival rate and lowest mortality were also observed in T5 and T6. The enhanced overall growth of mangosteen seedlings in T5 and T6 can be attributed to the inoculation of microbial consortium, which assisted in biological nitrogen fixation, phosphate solubilization, micronutrient mobilization, production of growth promoters (IAA, Cytokinin, & Gibberellin). Additionally, they enhanced root surface area, thereby improving nutrient and moisture absorption and highest seedling survival rate by imparting physical blockage to entry by pathogens, inducing systemic resistance, and producing antimicrobial compounds (peptides and polypeptides), besides producing exopolysaccharides which improved soil aggregation, leading to better water retention and aeration. Furthermore, the foliar application of NPK (3:1:1) promoted vegetative growth by involving in the photosynthesis process. In the third experiment, ‘Impact of balanced nutrition on the development of mangosteen’, the application of balanced nutrition in the treatments T4 (460:180:600 g NPK + 50 kg FYM + 600 g calcium nitrate + 80 g borax/tree/year) and T5 (460:180:600 g NPK + 3 kg neem oil cake + 2 kg bone meal + 600 g calcium nitrate + 80 g borax/tree/year) remarkably improved vegetative growth characters {mean canopy diameter (6.72 & 6.58 m), new flush leaf breadth (11.33 & 10.63 cm)}, biochemical contents {total chlorophyll (1.707 and 1.667 mg/g) and carotenoids (0.268 and 0.259 mg/g)}, yield attributes {yield per tree (15.68 & 13.60 kg) and yield per hectare (2.445 & 2.122 t)}, fruit quality traits {vitamin-C (18.67 & 17.34 mg/100mg) and overall acceptability (7.80 & 7.70)}. Besides, it also improved the availability of key nutrients {N (389.19 & 352.56 kg/ha) and B (0.70 & 0.68 ppm)} in soil and in plant {N (2.68 & 2.57%) and B (15.50 & 14.75 mg/kg)}. Additionally, from the economic point of view, the highest gross (6,12,500 & 5,30,000 Rs/ha) and net returns (5,08,237 & 4,13,881 Rs/ha) along with excellent benefit-cost (B:C) ratio (4.87 & 3.56 respectively) were documented in the treatments T4 and T5. The superior results obtained could be due to the availability of all essential nutrients in sufficient quantities in the leaves, achieved through the integrated application of organic and inorganic nutrient sources. This nutrient availability might have supported the synthesis of chlorophyll and carotenoids, subsequently, favouring the overall growth of trees, indicating the use of balanced nutrition for profitable commercial mangosteen cultivation. Both in T4 and T5, the whole quantity of P, FYM, neem oil cake, bone meal and 25% of N and K were applied as basal dose (October). The remaining N and K were applied in 3 splits (December, flowering, and fruit development stage). Additionally, calcium nitrate and borax were applied in the soil one week later after the 3rd (flowering stage) and 4th (fruit development stage) split application of N and K. In the fourth experiment ‘Role of bio-stimulants on the performance of mangosteen’, foliar application of biostimulants in treatments T6 (seaweed extract spray at 2%), T5 (seaweed extract spray at 1.5%), and T8 (humic acid spray at 1% + seaweed extract spray at 1%) were found to significantly enhance majority of the growth metrics {mean canopy diameter (6.28, 6.08 & 5.83 m) and new flush leaf breadth (11.70, 11.20 & 10.90 cm)}, biochemical contents {total chlorophyll (1.794, 1.742 & 1.706 mg/g) and carotenoids (0.282, 0.272 & 0.267)}, yield attributes {yield per tree (21.72, 18.76 & 18.24 kg) and yield per hectare (3.39, 2.93 & 2.85 t)} and fruit quality traits {total sugar (15.44, 14.68 & 14.75 %)} respectively. In addition, it also enhanced nutrient status in plant tissues {N (3.08, 2.94 & 2.80%), P (0.22, 0.20 & 0.19%), K (3.37, 3.12 & 2.85%), and Ca (0.89, 072 & 0.68%)}. Further, from the economic point of view, the highest gross (8,47,500, 7,32,500 & 7,12,500 Rs/ha) and net returns (6,12,091, 5,06,447 & 6,00,359 Rs/ha) along with high benefit-cost (B:C) ratio (5.90, 5.08 & 5.35) were also observed in treatments T6, T5, and T8 respectively. The superior outcome could be attributed to foliar spray with seaweed extract, which contained proteins, carbohydrates, macro- and micronutrients, phytohormones, amino acids and polysaccharides in addition to the presence of antioxidants (which protects oxidative stress), and vitamins (further support overall plant health). The role of humic acid was also significant, as it aided in nutrient chelation, improved nutrient availability and cation exchange capacity, and provided amino acids, peptides, and essential trace elements. These components collectively contributed to numerous biochemical processes, primarily enhancing photosynthesis and overall plant growth which substantiates the economic advantage of using biostimulants for enhancing the productivity and profitability of mangosteen cultivation. To conclude the results, seed treatment with microbial consortium (100 g/kg of seeds){PGPR Mix-1 + Piriformospora indica or Arka Microbial Consortia (AMC)} led to better germination and superior initial growth characteristics of seedling. When three-month-old seedlings were inoculated using microbial consortium sprayed with NPK {PGPR MIX-1 (10 g/plant) + AMF-Glomus fasciculatum (5 g/plant) + foliar spray NPK (3:1:1) at 0.5 %) or Arka Microbial Consortia (20 g/plant)} resulted in significant seedling growth and development. Further, higher yield, good quality of fruits, and high B:C ratio could be achieved through the application of 460:180:600 g NPK + 50 kg FYM + 600 g calcium nitrate + 80 g borax/tree/year or 460:180:600 g NPK + 3 kg neem oil cake + 2 kg bone meal + 600 g calcium nitrate + 80 g borax/tree/year in the soil. Additionally, foliar spray of bio-stimulants {seaweed extract spray (2% or 1.5%) or combined spray of humic acid (1%) + seaweed extract (1%)} gave excellent B:C ratio with superior quality fruits and higher yield in mangosteen. Based on the study conducted, research is needed to standardize a comprehensive nutrient package of practice of nutrients from seed to commercial yielding stage. Growth and development of mangosteen seedlings to a greater extent rely on environmental factors, such as optimum shade level, relative humidity, and temperature. As seed propagation is associated with long gestation period, alternative and more efficient methods for propagation has to be explored. Furthermore, fruits are with short shelf life and to address this challenge, development of improved storage, packaging, and handling techniques for extending the fruits shelf life is essential. It is also needed to focus on formulating effective integrated pest management (IPM) strategies for controlling the emerging insect pests such as mangosteen caterpillars, thrips and so on, through a detailed study.