1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
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Item Sensor based nutrient management in Tomato (Solanum lycopersicum)(Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, 2026-02-09) Mayoora Shaji; Rekh, V R NairThe study entitled ‘Sensor based nutrient management in tomato (Solanum lycopersicum)’ has been carried out at the Department of Soil Science and Agricultural Chemistry, College of Agriculture, Vellayani, during 2023-2025. The objective of the study was to compare soil test values obtained through different sensors and laboratory analysis; Yield assessment to analyse the efficiency of the sensor using tomato as the test crop. The study was carried out in two parts. The first part focused on comparing nutrient analysis across different cropping systems using sensor-based measurements and conventional laboratory analysis. Surface soil samples (0-15 cm) were collected from four land-use systems, , vegetable-based cropping system, coconut-based mixed farming, homestead farming, and fallow land within AEU 8. Five samples were collected from each system using the standard soil sampling procedure, with one composite sample taken for every 20 cents of area. Two portable sensors were deployed to measure soil nutrients at each location. Sensor 1 (Modbus) provides primary nutrient estimates (N, P, K) using an electrical-conductivity-based sensing principle. Sensor 2 (NutRE) measures primary (N, P, K), secondary nutrients (Ca, Mg, S), and selected micronutrients (Fe, Zn, Cu) through an ion-sensing mechanism, with further technical details withheld due to a pending patent. For field measurements, six random sampling points were selected within each 20-cent area, matching the locations used for conventional soil sampling. Modbus readings were taken at two points and averaged, and this procedure was repeated across the remaining 3-6 randomly selected spots within each location. The same sampling approach was applied for the NutRE sensor. The mean nutrient values obtained from both sensors were then compared with corresponding laboratory measurements. The Modbus sensor (Sensor 1) showed no significant difference (p > 0.05) for P under all land-use systems and across all computed mean levels (M2—M6), indicating close agreement with laboratory values for these parameters. However, N and K showed significant deviation (p = 0.00), suggesting the need for calibration for these nutrients. In contrast, the NutRE sensor demonstrated non-significant differences (p > 0.05) for all measured nutrients (N, P, K, Ca, Mg, S, Fe, Zn, Cu) across all land-use systems and mean levels, reflecting strong alignment with laboratory analysis. Variation in the number of readings used for mean calculation (M2—M6) did not significantly influence sensor accuracy for either sensor. Therefore, adopting the minimum mean level (M2) was adequate for accurate nutrient estimation across all systems, improving operational efficiency by reducing sampling time and field effort. The second part involved a field experiment that assessed sensor efficiency through tomato (cv.Anagha) yield evaluation, where the performance of both sensors was compared against soil test-based nutrient management. The experiment consisted of five treatments: T: (STB) — Split application of N P K as per soil test data (laboratory analysis). Tz (MDS-Nb) — Split application of N P K as per sensor | reading at 15 days interval up to beginning of harvest (Modbus sensor without basal). Ts (NutRE-Nb) — Split application of N P K as per sensor 2 reading at 15 days interval up to beginning of harvest (NutRE sensor without basal). Ts (MDS-B) — NPK application as basal dose based on Ist sensor data and further split up at 15 days interval (Modbus sensor with basal). Ts (NutRE-B) — NPK application as basal dose based on 2nd sensor data and further split up at 15 days interval (NutRE sensor with basal). Biometric observations revealed, at harvest, T: recorded the highest plant height (61.17 cm), while Ts produced a significantly greater number of branches (4.81). Leaf Area Index was highest under T; (2.59). With respect to yield attributes, T: produced a significantly greater number of fruits per plant (34.81), and the maximum fruit yield per plant (1.10 kg) while Ts (35.65g) produced highest fruit weight. Post-harvest soil analysis revealed significantly higher available N (210.12 kg ha‘) and K (207.20 kg ha"') under Ti, whereas Ts recorded the highest available P (85.20 kg ha‘). Plant nutrient analysis conducted at 15 and 30 DAT showed that Ts consistently recorded maximum NPK content during early crop growth, while at harvest, N and K contents were highest in T, and P content was highest in Ts. A similar trend was observed in nutrient uptake. Economic analysis showed that Ti yielded the highest gross income (Rs. 720,254.80) and B:C ratio (1.81), closely followed by Ts. T-test and Absolute Error Percentage (AEP) results showed that NutRE sensor accurately estimated all nutrients, with non-significant differences from laboratory values. Modbus sensor was reliable for phosphorus, while nitrogen and potassium required calibration to match laboratory standards. Field experiments revealed that soil test-based nutrient management T: (STB) achieved the highest yield, which was statistically comparable to the calibrated NutRE-based treatment Ts (NutRE-B). These results confirm that sensor-based nutrient management becomes effective only when supported by proper calibration and the inclusion of basal nutrient doses.Item Influence of fundamental motives on retention of certified organic farmers in Kerala agricultural development society, Thodupuzha(College of Co-operation, Banking and Management, Vellanikkara, 2026-09-12) Devika, C G; Biju Thomas MuttathItem Awareness and adoption of farm mechanisation by rice farmers in Palakkad district(College of Co-operation,Banking & Management, Vellanikkara, 2023-09-13) Thomson James; Divya VijayanItem Etiology and management of leaf spot disease of arecanut in northern Kerala By: Bhavana, A S(Department of Plant Pathology, College of Agriculture, Padannakkad, 2026-02-19) Bhavana, A S; Sajeesh, P KThe study entitled “Etiology and management of leaf spot disease of arecanut in Northern Kerala” was carried out in the Department of Plant Pathology, College of Agriculture, Padannakkad during 2023-2025 with the objective of etiology of the fungal pathogen/s associated with the leafspot disease of arecanut and to formulate management strategies against the disease. A purposive sampling survey was conducted in four AEUs of Kasaragod and Kannur districts to collect infected and healthy leaf of arecanut leaf spot disease affected palms samples. The fungi associated with the leaf spot symptoms were isolated and characterised. Pathogenicity tests revealed that twelve isolates were pathogenic, producing symptoms within 12–15 days after inoculation. These twelve pathogenic isolates were subsequently sent to the Rajiv Gandhi Centre for Biotechnology (RGCB), Thiruvananthapuram, for molecular characterization. Among the six isolates three isolates showed high similarity with Colletotrichum arecicola which is reported for the first time on arecanut in India. The contents of nitrogen (N), potassium (K), calcium (Ca), magnesium (Mg), and boron (B) were analysed in both healthy and diseased leaf samples collected from various locations and AEUs. A total set of healthy and diseased leaf samples were analysed using standard protocols. It was found that K level was consistently higher in healthy samples compared to diseased ones, indicating the role of K in enhancing disease resistance. Nitrogen and magnesium showed variable patterns depending on the AEU and did not follow a uniform trend. Calcium content was generally higher in healthy leaves, except in the leaves collected from AEU 13. Boron levels tended to be higher in diseased leaves suggesting a possible stress induced accumulation. Phylloplane microorganisms were isolated from the healthy arecanut leaves. These were evaluated for antagonism towards Colletotrichum arecicola using dual culture technique. Among them, two Trichoderma- like fungal isolates and one-gram negative bacterial isolate exhibited strong inhibition of the predominant pathogen C. arecicola. Under in vitro evaluation of fungicides against C. arecicola by poison food technique, mancozeb (75WP) at 0.2%, propiconazole (25EC) at 0.2% and carbendazim 12% + mancozeb 63% (75 WP) at 0.2% exhibited high inhibition (100%). These three fungicides, along with the antagonists selected from phylloplane used for in vivo evaluation against the disease. Fungicides and antagonists were applied one week after pathogen inoculation on leaves. After 15 days of fungicide application, propiconazole (25 EC) at 0.2% and carbendazim 12% + mancozeb 63% (75 WP) at 0.2% were found effective against arecanut leaf spot. The study identified as C. arecicola is the major cause of arecanut leaf spot in Northern Kerala, and it reported for the first time on arecanut in India. Nutrient analysis showed that higher potassium levels were associated with healthier leaves. Among the management options tested, propiconazole (25 EC) at 0.2% and carbendazim 12% + mancozeb 63% (75 WP) at 0.2% were the most effective in reducing disease severity. The findings are helped to learn more about the etiology of the leaf spot disease and in developing improved fungicide and fertilizer schedules for managing arecanut leaf spot disease.Item Characterization of pathogens causing canker and dieback diseases in moringa (Moringa oleifera Lam.)(Department of Plant Pathology, College of Agriculture, Vellanikkara, 2026-02-06) Adithya Sreekumar; Anju, CCanker and dieback are increasingly recognized as major constraints in moringa cultivation, despite the crop’s well-known resilience and rich phytochemical defence. Field observations across Kerala have indicated a rising incidence of these diseases affecting young and mature plants alike, yet systematic documentation of the causal pathogens and their interaction with the host remains limited. The present investigation was undertaken to identify, characterize and evaluate the pathogenic potential of fungi associated with canker and dieback diseases of moringa, and further to assess host biochemical responses at critical developmental stages. The study was carried out in the Department of Plant Pathology, College of Agriculture, Vellanikkara, from 2023 to 2025. A purposive survey of moringa-growing homesteads and nurseries in Thrissur (AEU 10) and Ernakulam (AEU 12) districts yielded a total of 65 diseased samples from which 77 fungal isolates were obtained, comprising 50 from canker-affected tissues and 27 from dieback samples. Disease intensity varied among locations, with the highest PD1 for canker recorded at Kolazhy (AEU 10) (89.28 %), while the maximum PD1 for dieback was recorded at Kothamangalam (AEU 12) (76 %). Several samples yielded multiple isolates, indicating the coexistence of distinct fungal species within the same lesion. Isolates were purified using hyphal-tip culture and maintained on PDA for further studies. Canker symptoms under natural conditions included superficial bark cracking, pale-yellow to light-brown sunken or flat lesions and localized necrosis. Dieback symptoms, on the other hand, were characterized by progressive twig/branch drying, extensive cortical discoloration and the appearance of black, pinhead-like pycnidial structures on severely affected tissues. Pathogenicity testing conducted under rain-shelter conditions confirmed the ability of all tested isolates to reproduce disease symptoms on moringa, fulfilling Koch’s postulates. Symptom development varied markedly among isolates, indicating a wide spectrum of virulence. Cultural and morphological characterization of the isolates revealed considerable diversity in colony growth, pigmentation, sporulation and microscopic traits. Isolates associated with canker generally produced fast-spreading, cottony to fluffy mycelium with pink, white, or grey colouration, while dieback-associated isolates commonly showed dark, melanised mycelium with abundant pycnidial formation. Molecular characterization using ITS, TEF-1α and RPB2 gene regions confirmed the presence of multiple pathogenic species on moringa. Canker symptoms were associated with Fusarium irregulare, F. citri, Nectria sp. and Lasiodiplodia theobromae, whereas dieback was predominantly caused by L. theobromae, Curvularia sp. and Diaporthe batatas. This represents the first comprehensive documentation of the canker-dieback pathogen complex occurring on moringa in Kerala. Extracellular cellulases and pectinases production was evaluated using substrate-amended media. All isolates exhibited measurable cellulolytic and pectinolytic activity. Among the 77 tested isolates, several, including Fusarium sp. (AIS5), Fusarium sp. (VLD2), Lasiodiplodia sp. (VLD1), Fusarium sp. (MAD), Curvularia sp. (MLD2) and Curvularia sp. (AVD3), produced large hydrolytic zones (mm) within just 2-3 days, reflecting a strong enzymatic activity. Statistical analysis 2 revealed a highly significant positive correlation between lesion size and enzyme activity, indicating that both cellulase and pectinase secretion are strongly linked to virulence expression. Two highly virulent isolates, L. theobromae, CHS2 (canker) and L. theobromae, TRD1 (dieback), were selected for biochemical assays. Host response was examined at five principal developmental stages: leaf, shoot, flowering, fruiting and senescence. CHS2 produced small, slowly enlarging lesions across all developmental stages, beginning as light-brown or pale-yellow spots (0.1-0.2 cm) that expanded slowly and developed into ovoid to spindle-shaped forms with mild cracking by day five. In contrast, TRD1 generated faster-expanding lesions even in early stages, initial pale brown patches (0.1-0.2 cm) rapidly enlarged (up to 2.5 cm by day 5) and frequently coalesced, progressing from pale yellow or water-soaked patches to darker brown or black lesions. Overall, CHS2 showed slower, stage-dependent lesion expansion, whereas TRD1 exhibited rapid, aggressive lesion development across all growth stages. Total phenolic content varied widely among growth stages and according to pathogens. In the flower development stage, inoculated plants accumulated substantially higher phenols than controls from one day after pathogen inoculation, indicating a pronounced early defence response. Conversely, in leaf and fruit development stages, phenol levels in inoculated plants dropped significantly below those of the corresponding controls, suggesting growth stage-specific phenol biosynthesis in response to pathogen infection. During senescence, phenol levels remained low across TRD1 inoculated treatment, reflecting a natural decline in defence capacity. Flavonoid content showed a transient decline at one to two days post inoculation across most developmental stages. This was followed by a clear rebound on days three and five, especially in the leaf and shoot development stages, reflecting induced defence activation. In the leaf development stage inoculated with CHS2, flavonoids increased markedly by day five (22.85 mg QE g⁻¹; ~26% above control). TRD1-inoculated tissues displayed a similar pattern of early reduction followed by strong accumulation of flavonoids from day three. Overall, the study establishes that canker and dieback in moringa are caused by a diverse assemblage of fungal pathogens exhibiting wide variability in virulence and extracellular enzyme activity. The findings highlight the central role of cell-wall degrading enzymes in facilitating tissue colonization and disease progression. Moreover, phenolic and flavonoid profiling across growth stages reveals that moringa exhibits a highly stage-dependent defence strategy, with stronger biochemical activation during early vegetative growth and flowering stages and weaker responses during fruiting and senescence. These insights form an essential foundation for developing stage-specific disease management strategies and for future exploration of host resistance mechanisms in moringa.Item Host plant resistance in cowpea (vigna unguiculata (L.) Walp) against Aphis craccivora Koch (Hemiptera: Aphididae)(Department of Entomology, College of Agriculture, Padannakkad, 2026-02-16) Aiswarya Mohan, S; Thania Sara VargheseThe present study titled ‘Host plant resistance in cowpea (Vigna unguiculata (L.) Walp) against Aphis craccivora Koch (Hemiptera: Aphididae)’ aimed to assess the resistance or susceptibility of cowpea germplasms to A. craccivora and to identify the mechanisms underlying this resistance through antixenosis, antibiosis and biochemical analyses. Field screening of thirty-two cowpea germplasms was conducted from January to March 2025 at Instructional Farm I, College of Agriculture, Padannakkad, under natural infestation conditions. In the field evaluation, Kashi Nidhi (13.27) recorded highest number of aphids per 2.5 cm shoot and Kashi Gauri the lowest (0.15). Other insect pests such as stem fly, leaf miner, leaf roller and cow bug were also observed, though significant differences were noted only in stem fly and leaf miner incidence. Stem fly damage was highest in Lola (6.33) and lowest in Konkan Wali (0.00), while leaf miner incidence was greatest in TCR 57 (1.13) and lowest in Lola, KAU Sreenandha, TCR 53, TCR 36 and Maharashtra local variety 3(0.00). Despite these variations, no visible foliar or floral damage attributable to aphids was recorded, and population differences alone were insufficient to categorise the entries into resistant/ susceptible under field conditions. In that context, cage screening was conducted that provided a clearer separation of germplasm response to A. craccivora. Seedling survival after release of aphids was found to be highest in Arka Samrudhi (41.67) and lowest in Geethika, Karkoonthal Payar and Maharashtra Local variety 3 (15). Damage assessments showed a comparable pattern, with Geethika, Karkoonthal payar and Maharashtra local variety 3 recording the highest cumulative scores (5.00) and Arka Samrudhi (2.11) the lowest. None of the germplasms were categorized as highly resistant or resistant; five were classified as moderately resistant (MR), nine as moderately susceptible (MS), and eighteen as highly susceptible (HS). Two germplasms from each category - MR (Anaswara, Arka Samrudhi), MS (Konkan Wali, Phule Pandhari), and HS (Geethika, Karkoonthal payar) were selected for studying host plant resistance mechanisms. Antixenosis (non-preference) studies on the six selected germplasms revealed that mean number of aphids migrated per plant was highest in highly susceptible 98 Geethika (90.50) and lowest in moderately resistant Arka Samrudhi (23.25). The selected germplams showed an effect on growth, reproduction and survival of the aphids. The mean weight of 10 aphids and number of progeny per aphid were maximum in Geethika (7.32 mg and 21.00, respectively) and the mean survival period was highest in Karkoonthal payar (10.25 days), whereas Arka Samrudhi recorded the lowest values for all three parameters (4.68 mg, 6.75 progeny, and 6.75 days, respectively). The results indicate that highly susceptible genotypes promote aphid development and survival whereas moderately resistant types suppress growth, reproduction and longevity. Biochemical and nutrient estimation of the selected MR and HS germplasms showed that nitrogen, phosphorus, potassium and protein contents were highest in Karkoonthal payar (5.45%, 0.48%, 4.72% and 340468.75 µg g⁻¹ respectively) and lowest in Arka Samrudhi (3.35%, 0.24%, 2.66%, 209531.25 µg g⁻¹respectively). The total phenol content was highest in Anaswara (381.56 µg g-1) and lowest in Geethika (186.21µg g-1), and both flavonoid and terpenoid levels were highest in Arka Samrudhi (1326.26 µg g-1, 4775.83 µg g-1) and lowest in Karkoonthal payar (496.43 µg g-1, 2309.24 µg g-1). The highly susceptible Geethika showed maximum plant height (142.80 cm) and number of primary branches (7.75), while moderately susceptible Phule Pandhari (29.15 and 3.00 respectively) recorded the lowest values. Number of leaves/plant were highest in Anaswara (17.75) and lowest in Phule Pandhari (9.25). Trichome density was greatest in Karkoonthal payar (21.50/cm leaf margin) and lowest in Anaswara (14.75/cm leaf margin), whereas trichome length was longest in Anaswara (0.42 mm) and shortest in Karkoonthal payar (0.10 mm). In the present study, principal component analysis clearly separated resistant and susceptible germplasms, with Arka Samrudhi and Anaswara clustering opposite Geethika and Karkoonthal payar, showing that resistance was associated with higher biochemical defenses and longer trichomes, whereas susceptibility clustered with elevated nutrient levels and stronger aphid performance traits.Item Genetic diversity analysis and in vitro seedling production of mangosteen (Garcinia mangostana L.) accessions(Department of Fruit Science, College of Agriculture, Vellayani, 2026-02-09) Harsha, K S; Simi, SThe study entitled “Genetic diversity analysis and in vitro seedling production of mangosteen (Garcinia mangostana L.) accessions” was conducted at the Department of Fruit Science and the Department of Molecular Biology and Biotechnology, College of Agriculture, Vellayani, during the period 2023–2025. The investigation aimed to assess the genetic diversity of mangosteen accessions using molecular markers and in vitro seedling production to enhance seedling vigour. Thirty mangosteen genotypes cultivated in Thrissur and Wayanad districts of Kerala were subjected to molecular characterization. Genomic DNA was isolated from young leaves using the CTAB extraction method (Doyle and Doyle, 1987) with modifications proposed by Sulassih and Santosa (2020) incorporating polyvinylpyrrolidone (PVP) to eliminate polyphenolic impurities. The DNA samples showed UV absorbance ratios (A260/A280) between 1.79 and 2.07 indicating their purity. Ten Inter Simple Sequence Repeat (ISSR) primers, previously reported in mangosteen, were used for amplification. These primers produced a total of 71 loci across the thirty genotypes of which 63 were polymorphic resulting in a mean polymorphism percentage of 85.87%. The number of loci per primer varied from 3 (UBC 860) TO 11 (UBC 840) indicating considerable variation in amplification efficiency. The Polymorphic Information Content (PIC) values ranged between 0.04 (UBC 860) and 0.39 (UBC 825) with an average of 0.28, indicating moderate informativeness. Cluster analysis using the Unweighted Pair Group Method with Arithmetic Mean (UPGMA) based on Jaccard’s similarity coefficients revealed three major clusters at a similarity coefficient of 0.66 corresponding to 34% dissimilarity. Cluster I comprised a single accession (Acc. 017) that was distinctly separated indicating a high degree of divergence. Cluster II containing twenty six accessions was further divided into subclusters II A and II B at 0.68 similarity, while Cluster III included three accessions (Acc.004, Acc.048, and Acc.126). Principal Coordinate Analysis (PCA) further supported the clustering pattern, indicating the moderate genetic differentiation among the genotypes. Investigations were also carried out for in vitro seedling production of mangosteen. Mature seeds of mangosteen were aseptically cultured on Murashige and Skoog (MS) and 85 half-strength MS media containing different concentrations of sucrose (1%, 2%, and 3%) and gibberellic acid (GA₃) (0, 0.2, 0.5, and 1 ppm). Twelve treatment combinations were evaluated for their influence on germination, subsequent seedling vigour and growth. Significant variation was observed among treatments for all parameters studied. The mean number of days required for germination ranged from 12.33 to 22.67 days. The earliest germination was observed in treatment T₁₂ (½ MS + 2% sucrose + GA₃ 1 ppm). Similarly the germination percentage also varied significantly, with T₁₂ showing the highest value (95.24%) followed by T₁₀ (½ MS + 2% sucrose + GA₃ 0.2 ppm). Seedling vigour indices (SVI-I and SVI-II) reflected a similar trend with T₁₂ recording the highest values (1383.81 and 44.48, respectively), indicating the positive influence of reduced salt concentration and GA₃ supplementation on germination and early growth. Growth parameters recorded at the time of plant out revealed significant differences among treatments. The longest shoots (5.73 cm), roots (3.87 cm) and leaves (4.77 cm) were recorded in T₁₂. After four weeks of hardening, seedlings from T₁₂ maintained superior performance with the highest shoot length (7.10 cm), root length (7.17 cm), and leaf length (6.17 cm). The number of leaves was the highest in T₈ (MS + 2% sucrose + GA₃ 0.5 ppm) and T12 (½ MS Media (2% sucrose) + GA 1 ppm). Survival percentage did not differ significantly among treatments; however, T₁₂ and T₆ recorded the highest survival percentage (95.24), indicating the robustness of the developed seedlings. These results demonstrated that half-strength MS medium supplemented with 2% sucrose and 1 ppm GA₃ was optimal for inducing early germination, improving root and shoot elongation, and enhancing seedling vigour. The present study confirms the existence of genetic diversity among mangosteen accessions in Kerala despite their apomictic nature. The moderate polymorphism revealed by ISSR markers indicates underlying genetic differentiation likely resulting from somatic mutations or environmental adaptation. The optimized in vitro germination media (½ MS medium supplemented with 2% sucrose and 1 ppm GA₃) proved effective in enhancing germination, seedling vigour, and survival percentage.Item Production technology and post harvest handling techniques of orange jasmine (Murraya paniculata (L.)Jack)(Department of Floriculture and Landscaping, College of Agriculture, Vellanikkara, 2026-01-09) Nandana Bhaskaran; Simmy, A MOrange jasmine (Murraya paniculata (L.) Jack) is a tropical ornamental shrub belonging to the Rutaceae family, native to South and Southeast Asia, valued for its glossy foliage and aesthetic appeal in floral arrangements. The plant has gained commercial importance in the cut foliage industry, particularly in Kerala's favourable humid tropical climate. Despite its growing demand, the crop faces significant challenges due to non standardised agronomic practices and inadequate post-harvest handling techniques, resulting in reduced productivity and limited vase life, leading to substantial economic losses. The present study, entitled 'Production technology and post-harvest handling techniques of orange jasmine [Murraya paniculata (L.) Jack] was carried out at the Department of Floriculture and Landscaping, College of Agriculture, Vellanikkara, Thrissur, during 2024-2025 to standardise spacing, nutrient management protocols, and post-harvest handling techniques for commercial cultivation and vase life enhancement of orange jasmine foliage. The first experiment evaluated the effects of three plant spacings (1 m × 1 m, 1.5 m × 1.5 m, and 2 m × 2 m) and three nutrient doses (75:8:15, 100:8:15, and 50:8:15 N:P₂O₅:K₂O g/plant/year) on growth and yield parameters. Plant height was significantly affected by nutrient application; the 75:8:15 and 100:8:15 N:P₂O₅:K₂O treatments resulted in maximum heights of 127.66 cm and 126.55 cm respectively. The widest spacing (2 m × 2 m) combined with the highest nutrient dose produced the largest number of harvestable shoots (6.33 shoots). The greatest yield (5.49 t/ha) was observed at the closest spacing (1 m × 1 m), while the 100:8:15 N:P₂O₅:K₂O dose yielded 4.65 t/ha, and their combination resulted in the highest overall yield of 7.89 t/ha. The 2 m × 2 m and 100:8:15 N:P₂O₅:K₂O combination led to the heaviest shoots (159.39 g) and the shortest duration to first harvest (278.33 days). Maximum chlorophyll content (1.25 mg/g FW) was recorded at the 1 m × 1 m spacing, and 1.18 mg/g FW at the highest nutrient dose. The lowest nutrient dose N3(50:8:15 N:P₂O₅:K₂O) resulted in the longest vase life (13.33 days) The second set of experiments standardised post-harvest techniques through four sequential studies. Precooling treatments showed that the untreated control recorded the longest vase life of 13.26 days. Pulsing with BA 50 ppm extended vase life to 17.44 days, followed by BA 25 ppm (14.78 days), while the sucrose combinations reduced vase life. Packaging and storage experiments showed that polypropylene sleeves (P₄) and newspaper cover (P₇) with a 48-hour storage duration yielded optimal results. The combination of polyethylene sleeve with KMnO₄ sachet stored for 48 hours (P₃ × S₂) achieved the maximum vase life of 25.67 days. Holding solution experiments demonstrated that sodium benzoate treatments were most effective, with concentrations of 50 ppm and 100 ppm, extending vase life to 14.83 and 14.33 days, respectively. The present study demonstrated that the combination of optimal spacing (1 m × 1 m), and the highest nutrient dose (100:8:15 N:P₂O₅:K₂O g/plant/year) produced the highest yield proving that these treatments are best suitable for the cultivation of Murraya paniculata. For the post-harvest practices, omitting precooling, pulsing cut shoots with 50 ppm BA for 6 hours, packaging in polyethylene sleeve with KMnO₄ sachet for 48 hours, and using sodium benzoate as a holding solution maximized vase life. This research provides a comprehensive production and post-harvest management protocol to enhance commercial viability and promote a sustainable supply chain for the orange jasmine cut foliage industry in Kerala.Item Screening of brinjal genotypes (Solanum melongena L.) for resistance against the spider mite Tetranychus sp. (Acariformes :Tetranychidae)(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2026-02-13) Aishwarya, N; Neena LeninThe study titled “Screening of Brinjal Genotypes (Solanum melongena L.) for resistance to the spider mite, Tetranychus sp. (Acariformes: Tetranychidae)” was conducted at the Department of Entomology, College of Agriculture, Vellayani, between 2023 and 2025. The major objective of this study was to screen brinjal genotypes for their resistance to spider mites and to identify the underlying antixenotic mechanisms of resistance. The field tolerance of 25 brinjal genotypes was evaluated in the field as per the KAU POP, and the total number of spider mites (eggs, nymphs, and adults combined) per leaf was counted. The genotypes were then classified into six categories based on their mean mite population per leaf as highly resistant, resistant, moderately resistant, moderately susceptible, susceptible and highly susceptible. Out of the 25 genotypes screened, none were found to be highly resistant or highly susceptible. Six genotypes, namely Pusa Uttam, Poluru Vankaya, Anjamile Local, FM-183, Surya, and Arka Anand, expressed resistance; eight were moderately resistant; six were moderately susceptible, and five genotypes, namely VRM-1, Pusa Krishna, VJ Crystal, KAU Local, and Nandyala Local, were susceptible. Additionally, the study examined the influence of morphological traits like trichome density, trichome type, trichome length, trichome angle, and cuticle thickness, on the extent of mite infestation. Statistical analysis using Principal Component Analysis (PCA) revealed that trichome density had a strong negative correlation with mite populations (r = -0.90), accounting for 42.49 per cent of the variability in the first principal component (mean mite population). Trichome density and structural complexity were the principal determinants of resistance, while trichome length and orientation exerted a secondary influence. Six distinct non-glandular trichome types were identified across the evaluated genotypes, most of which were porrect-stellate multiradiate trichomes, differing in the number of subulate rays (2-12) and the presence or absence of a pedestal. Genotypes 107 possessing long central rays and pedestals- such as Pusa Uttam, Arka Anand, and Poluru Vankaya, etc. exhibited resistance, whereas those with shorter central rays, including VRM-1, Nandyala Local, and Maruthadukkam Local, were susceptible. The mites collected from brinjal it was identified as Tetranychus macfarlanei Baker & Pritchard (Gupta and Gupta, 1994). Further studies showed that T. macfarlanei completed its life cycle on all genotypes, but performance varied with host genotype. On the susceptible genotype VRM-1, mites exhibited the shortest developmental duration (5.15, 2.30, 5.94, 5.83 and 11.78 days for incubation, larval period, nymphal period, adult male and adult female longevity, respectively), highest fecundity (85.2 eggs/female), and larger body size, indicating higher host suitability. In contrast, resistant genotypes (Anjamile Local, Surya, Poluru Vankaya, Pusa Uttam, and FM-183) supported lower fecundity (42.6-55.2 eggs/female), prolonged oviposition (11.50-12.35 days), and smaller adults, confirming the non-suitability of host on mite reproduction and development. Biochemical analysis revealed distinct variations among the genotypes in their defensive metabolite composition. Resistant genotypes recorded higher levels of total phenols (0.037-0.046 mg g⁻¹), tannins (1.55-1.68 mg g⁻¹), lignin (0.093-0.324 mg g⁻¹), and silica (2.29-5.42 mg g⁻¹), whereas the susceptible genotype VRM-1 exhibited lower concentrations of these metabolites, with 0.031 mg g⁻¹ phenols, 1.50 mg g⁻¹ tannins, 0.057 mg g⁻¹ lignin, and 1.50 mg g⁻¹ silica. Upon infestation, resistant genotypes showed an increase in phenolic (0.043-0.060 mg g⁻¹) and tannin content (1.62-1.77 mg g⁻¹), indicating an induced biochemical response. VRM-1 recorded higher levels of total soluble sugars (5.33 mg g⁻¹) and reducing sugars (3.55 mg g⁻¹) compared to resistant genotypes, leading to the host preference. These observations suggest that resistant genotypes maintain higher concentrations of defensive metabolites, while susceptible ones possess greater levels of nutritive compounds. The screening of 25 brinjal genotypes revealed clear differences in resistance to T. macfarlanei. Resistant genotypes exhibited antixenosis through higher trichome density, complex trichome structures, and elevated defensive metabolites, which reduced mite preference, feeding, and reproduction.Item Dynamics of co-operative credit and its impact on agricultural development in Kerala(Department of Agricultural Economics, College of Agriculture, Vellayani, 2026-02-11) Divyapriya Rahul; Anil KuruvilaThe thesis titled “Dynamics of co-operative credit and its impact on agricultural development in Kerala” examines the long-term development and role of co-operative agricultural credit in Kerala and its impact on agricultural growth and farmers’ livelihoods during the period from 1980-81 to 2022-23. Co-operative institutions, especially Primary Agricultural Credit Societies (PACS) and Primary Co-operative Agricultural and Rural Development Banks (PCARDBs), have been important sources of rural finance in Kerala. They provide loans to farmers for crop production, irrigation, machinery, plantation development, and other agricultural activities. Despite the importance, the distribution and effectiveness of co-operative credit have differed widely across districts and over time. This study aims to understand how co-operative credit has evolved, how it has contributed to agricultural development, and how it has affected individual farming households in Kerala. The study is based on both secondary and primary data. Secondary data were collected from government reports, institutional records, and official databases relating to co-operative credit and agricultural development. These data cover all districts of Kerala and span more than four decades. Primary data were collected from 160 farmer borrowers selected from four districts, viz., Pathanamthitta, Alappuzha, Malappuram, and Palakkad. These districts were chosen to represent areas with low and high levels of credit disbursement and different agricultural systems. This combination of data sources enabled a comprehensive analysis of both long-term trends and household-level impacts. The analysis was guided by three main objectives. The first objective was to examine the changing pattern and growth of co-operative credit in Kerala. The second objective was to assess the contribution of co-operative credit to agricultural development, while the third objective was to study the impact of co-operative credit on farmers’ income and standard of living. Various statistical and econometric tools such as growth rate analysis, inequality measures, cointegration tests, causality analysis, and regression models were used to achieve these objectives. ii To study the growth and performance of PACS and PCARDBs, the entire study period was divided into three phases, which were identified on the basis of structural break analysis. The first phase (1980-81 to 2001-02) was a period of rapid expansion and institutional strengthening. During this period, most districts experienced strong growth in membership, deposits, share capital, working capital, and credit disbursement. Farmers increasingly trusted co-operative institutions and deposited their savings in them. Deposit mobilisation became the main source of funds, which reduced excessive dependence on external borrowing. Both short-term crop loans and long-term investment loans expanded, indicating rising agricultural activity and investment. However, some districts such as Kottayam and Thrissur showed relatively weaker growth, suggesting early signs of saturation or limited investment demand. The second phase (2002-03 to 2011-12) was a period of transition. During this period, the growth of co-operative institutions slowed down in many districts. Competition from commercial banks, the spread of Kisan Credit Card scheme and changes in rural finance policies affected the functioning of PACS. Deposit mobilisation continued, but growth in share capital weakened in several regions. As a result, co-operatives became more dependent on borrowings from higher financing agencies. While some districts such as Palakkad, Kozhikode, and Malappuram performed relatively well, others like Wayanad, Kottayam, and Thiruvananthapuram recorded stagnation. Credit expansion also became concentrated among fewer borrowers in some areas, reducing inclusiveness. The third phase (2012-13 to 2022-23) represents a period of partial revival and institutional stabilisation. Membership and share capital increased in many districts, reflecting renewed confidence among farmers. Internal resource mobilisation improved, and dependence on external borrowings declined compared to the previous phase. Long term investment credit expanded in several districts, especially for plantation development, irrigation, and mechanisation. However, short-term and medium-term credit growth slowed in many regions due to increased competition from banks and digital credit platforms. Performance across districts remained uneven, with some districts showing balanced growth while others lagged behind. A similar analysis was carried out for PCARDBs, which mainly provide long term agricultural loans. In the first phase, several districts such as Wayanad, Palakkad, iii and Ernakulam recorded strong institutional and credit growth. However, dependence on external borrowings was high in many areas. In the second phase, institutional restructuring improved financial stability in some districts, but growth remained selective. In the third phase, long-term credit expanded sharply, indicating renewed investment activity, but this expansion was often supported by external funds rather than internal resources and as a result, concerns about the financial autonomy persisted. The study also analysed the regional distribution of medium-term and long-term co operative credit. The results showed that credit distribution in Kerala has been highly unequal across districts throughout the study period. A few districts such as Ernakulam, Kottayam, Thrissur, and Kollam consistently received a large share of investment credit, while districts such as Idukki, Wayanad, Kasaragod, and Alappuzha remained under served. Even after adjusting credit amounts based on cultivated area, inequalities remained high. This indicates that institutional strength, cropping patterns, and historical development play more important roles than land size in determining the credit access. Established co-operative networks and diversified commercial agriculture enabled certain districts to attract more credit, while weaker regions faced persistent constraints. To assess the contribution of co-operative credit to agricultural development, the study examined the long-term and short-term relationships between credit and agricultural indicators. The results show that co-operative credit has a stable relationship with cropping intensity, fertilizer use, irrigated area, plantation area, and agricultural output. This means that credit and agricultural development have moved together over time. In the short run, credit availability was found to encourage better farming practices and investment in agriculture. However, the impact of credit on output and income was gradual rather than immediate. The micro-level analysis based on primary data provides important insights into how farmers use co-operative credit. The sample farmers were mostly older, experienced cultivators with low levels of formal education and small landholdings. This reflects the ageing nature of agriculture in Kerala and limited participation of younger generations. Most households belonged to the medium-income category, with income levels influenced by crop diversification and non-farm activities.The study iv found that the amount of credit sanctioned to farmers was mainly determined by collateral availability and existing indebtedness rather than by actual production needs. Factors such as land size, education, and cultivation expenses had little influence on loan size. This indicates that lending decisions were guided more by institutional rules and risk considerations than by farm requirements. As a result, credit allocation was not always aligned with the productive potential. The study also found that farm income was influenced mainly by cultivated area, production expenditure, and farming experience. The amount of co-operative credit borrowed did not have a significant direct impact on income. This suggests that credit alone does not guarantee higher income unless it is used effectively for productive investments. The analysis of loan utilisation revealed that a considerable number of borrowers diverted loans for non-productive purposes such as household consumption, repayment of old debts, medical expenses, and coping with climatic or wildlife-related losses.. Consequently, co-operative credit often functioned as a means of stabilising household consumption and managing risks rather than promoting productive investment. The study concluded that Kerala’s co-operative credit system has expanded significantly over the past four decades and has played a vital role in supporting agricultural activities. However, its growth has been spatially uneven and institutionally driven. Investment-oriented credit was more unequally distributed than short-term crop loans, limiting development in weaker regions. At the macro level, co-operative credit supports agricultural intensification and structural transformation. At the micro level, its developmental impact is limited by risk-averse lending practices, ecological challenges, and diversion of funds. The study recommends increasing the share of long term investment credit, strengthening deposit mobilisation and share capital, adopting district-specific revival strategies, aligning credit with agro-ecological conditions, and linking credit with technology adoption and advisory services. It also emphasises the need for flexible lending products, better monitoring of loan utilisation, and incentive based repayment systems. Integrating credit with farm support services can improve productivity and repayment capacity. These measures can enhance the effectiveness of co-operative credit as a tool for sustainable and inclusive agricultural development in Kerala.