1. KAUTIR (Kerala Agricultural University Theses Information and Retrieval)
Permanent URI for this communityhttp://localhost:4000/handle/123456789/1
Browse
7 results
Search Results
Item Role of biostimulants on growth and yield of papaya(Carica papaya L.)(Department of Fruit Science, College of Agriculture , Vellanikkara, 2024-02-09) Anjana Mukesh; Aswini, APapaya (Carica papaya L.) is a most important fruit crop cultivated throughout the tropical and subtropical regions. The fruit is known for its sweet and musky flavour, making it a popular choice among the consumers. Papaya is rich in vitamins, particularly vitamins C, A and E. It contains enzymes called papain, which aids in digestion and is used for industrial purposes. The fruit is a good source of dietary fibre and antioxidants, contributing to overall health. The fruit's qualities and health benefits make papaya more appealing to customers. Drastic invasion of pests and diseases and scarcity of superior variety with higher yield are the major constrain for the economic production of papaya in Kerala. The uses of biostimulants on different horticultural and agronomic crops were gaining popularity due to their growth and development, quality enhancement and resilience to stress. In this background, the present study investigates on “Role of biostimulants on growth and yield of papaya (Carica papaya L.)” to evaluate its effect on the papaya variety “CO 7”. he biostimulants were applied every month and the observations were recorded at bimonthly intervals. Results indicated that significant variations were observed among treatments in various growth parameters. For instance, T2, involving chitosan and Sampoorna KAU Multimix, exhibited the minimum plant height at 120.47 cm and the plant collar girth was notably reduced (38.88 cm) after 10 months of growth in proportion to height. The application of biostimulants, especially chitosan and Sampoorna KAU Multimix (T2), significantly increased the number of leaves (23.44). In terms of flowering dynamics, significant differences were observed among treatments, with the earliest flowering in T2 at 108.77 days. Sex reversal were observed during the study encompassing male, female, bisexual and andromonoecious plants. The number of flowers per cluster reached its maximum in T1 (chitosan) at 4.97, while T2 demonstrated the highest fruit set percentage at 75.38%. The period from fruit set to maturity was notably shorter (131.61 days) and more number of days (6.72 days) for maturity to ripening reported in T2. Fruit parameters, including weight, length, girth, and volume, showed statistically significant differences among treatments, with T2 consistently recording the maximum values (1463.22 g, 24.32 cm, 40.95 cm, and 1283.33 cm3, respectively). Flesh thickness, fruit count and seeds per fruit also exhibited significant variations among treatments. Biochemical analyses further revealed distinct profiles. T2 demonstrated the highest total soluble solids at 14.11°Brix, while titratable acidity values were notably lower in T2, T1 and T4. T2 also showcased the highest total carotenoid content at 2.73 mg/100g, ascorbic acid content at 66.41 mg/100g and total sugar content at 11.81%. Shelf life was significantly longer in T2 at 8.61 days. Organoleptic evaluation scored the highest rank in T2 based on its overall appeal. Throughout the cropping period, the occurrence of diseases such as foot rot, Corynespore leaf spot, and viral infections in papaya crops was noted, showing no apparent relationship with the treatments applied in the current study. The application of chitosan has been associated with a reduction in viral diseases, as reported in earlier research works. However, to deepen our understanding and establish the potential of chitosan in mitigating viral diseases in papaya crops, further studies are imperative. In conclusion, the study highlights the superiority of the papaya variety CO 7, attributed to its impressive combination of high yield and superior fruit quality. Moreover, the application of biostimulants has proven to be instrumental in enhancing the overall growth, yield and quality of the papaya fruits. Notably, the efficient combination of Chitosan and Sampoorna KAU Multimix can give as a single spray, rather than separate spraying will reduce the labour cost. The application of combination of chitosan and Sampoorna KAU Multimix emerges as particularly promising, showcasing the potential to deliver higher economic benefits to farmers. The positive effects of Sampoorna KAU Multimix pave a way to standardize micro nutrient mixture for papaya as similar as practices established for banana. This finding current study underscores the importance of strategic biostimulant use in optimizing papaya production, offering valuable insight into agricultural practices aimed at improving crop outcomes, stress tolerance and economic returns.Item Molecular diagnosis and management of Papaya ringspot virus causing papaya ringspot diseases(Department of Plant Pathology, College of Agriculture,Vellayani, 2024-04-17) Josiya Joy; KAU; Radhika, N SThe research work entitled “Molecular diagnosis and management of Papaya ringspot virus causing papaya ringspot disease” was undertaken in the Department of Plant Pathology, College of Agriculture, Vellayani, Thiruvananthapuram, during 2019-24, with the objectives; molecular diagnosis and recombinant coat protein production of Papaya ringspot virus (PRSV), and evaluation of the efficacy of beneficial microorganisms and botanical inthe management of papaya ringspot disease (PRSD). Roving survey was carried out across five Agro-ecological units (AEUs) of Kerala. The disease incidence (DI) ranged from 50.25 per cent (Kayyur-Cheemeni) to 100 per cent (Kalliyoor, Venganoor, Balaramapuram, Pallichal, Kayamkulam, Mavelikkara, Velukkara, Irinjalakuda and Shoranur). Vulnerability index (VI) of the plants to PRSV in the surveyed locations ranged from 33.54 (Badiyadkka) to 98.22 (Kalliyoor). Serological and molecular detection confirmed the presence of PRSV in all the 20 symptomatic samples collected during survey. Phylogenetic tree constructed with the deduced amino acid sequences of CP gene of 11 Kerala PRSV isolates, revealed that Thiruvananthapuram isolates clustered together, indicating their relatedness during evolution. Mechanical inoculation on two months old Red Lady papaya seedlings under insect proof conditions was carried out to identify the most virulent PRSV isolate collected from different AEUs. At three months after inoculation (MAI), Kalliyoor isolate exhibited highest VI (96.63) followed by Alur (95.48) and Venganoor (95.22) isolates. The lowest VI was observed in Kayyur-Cheemeni isolate with 57.95 VI, followed by Cherpulassery (60.58). The recombinant coat protein of PRSV was induced in pLATE 31 expression vector with C terminal histidine tag, within BL21(DE3)pLysS expression host. PRSV recombinant coat protein was purified using Ni-NTA column chromatography. A single band was observed at 35 kDa in SDS-PAGE analysis and western blotting with PRSV antiserum, confirmed the presence of purified recombinant coat protein in the soluble fraction. Pot culture experiment was conducted to evaluate the management of PRSD using Piriformospora indica. The initial colonization of P. indica inside the papaya roots was observed five days after germination of the seeds grown in P. indica massmultiplied medium. Prophylactic colonization of P. indica exhibited lowest VI (23.10) and 68.27 per cent reduction in VI over control diseased plants at five months after PRSV inoculation (MAI). Double antibody sandwich - Enzyme linked immunosorbent assay (DAS-ELISA) at 5 MAI revealed lowest absorbance (0.23) indicating lowest virus titre in P. indica pre-colonized plants upon PRSV inoculation, compared to control diseased plants (1.23). The accumulation of reactive oxygen species (ROS) i.e., H2O2 and superoxides in the leaves were analyzed using DAB (diaminobenzidine) and NBT (nitro blue tetrazolium chloride) staining respectively. P. indica-colonized plants upon PRSV inoculation indicated a higher initial accumulation of ROS at three weeks after inoculation (3 WAI) and further reduction at 6, 9 and 12 WAI of PRSV, compared to control diseased plants. P. indica-colonized plants also exhibited enhanced antioxidant defence enzyme activity viz., catalase, peroxidase, polyphenol oxidase, phenylalanine ammonia lyase, glutamate synthase and superoxide dismutase compared to control diseased plants. Amongst PRSV inoculated treatments, P. indica pre-colonized plants exhibited highest number of leaves (20.86), leaf area (365.14 cm2), plant height (108.29 cm), stem girth (7.26 cm), shoot biomass (423.43 g), root biomass (133.96 g) and chlorophyll content (2.84 mg g-1 of fw) at five months after transplanting (5 MAT). Effect of P. indica, Bougainvillea spectabilis leaf extract (10 %) and Pseudomonas fluorescens (2 %) were evaluated against natural incidence of PRSD under field conditions at Instructional farm, College of Agriculture, Vellayani and Coconut Research Station, Balaramapuram, Thiruvananthapuram. P. indica-colonized plants exhibited lowest VI (37.63), with highest reduction in VI over control (53.85 %) followed by B. spectabilis treated plants (37.49 %) and P. fluorescens treated plants (33.31 %) at 12 months after planting (12 MAP). In DAS-ELISA, lowest virus titre with absorbance of 0.438 was observed in P. indica-colonized plants at 12 MAP, compared to the highest virus titre in control plants (1.267). B. spectabilis treated plants (0.596) also exhibited reduction in virus titre followed by P. fluorescens treated plants (0.625) at 12 MAP. P. indica-colonized plants exhibited enhancement in growth parameters viz., number of leaves (24.00), leaf area (1127 cm2), stem girth (42.74 cm) and plant height (207.39 cm) at 12 MAP. P. indica-colonized plants also enhanced the yield by 44.68 per cent followed by B. spectabilis treated plants (24.13 %) and P. fluorescens treated plants (17.99 %). Moreover, fruits from P. indica-colonized plants expressed significantly superior quality parameters. Thus, findings from the present study could aid in the preliminary detection and management of the virus, thus mitigating the widespread infection caused by PRSV. The recombinant PRSV coat protein produced in this study could be used for the development of PRSV antiserum. Additionally, our research highlights the efficacy of eco-friendly management strategies for papaya ringspot disease, with P. indica-colonization @ 106 cfu g-1 and also with four foliar sprayings as well as soil drenching of B. spectabilis leaf extract (10 %) applied at fortnightly intervals, starting from one month after planting. More field trials are to be conducted to integrate this strategy in integrated disease management (IDM) package for the effective and sustainable management of PRSD in papaya.Item Fertigation studies in papaya (Carica papaya L.)(Department of Fruit Science, College of Agriculture,Vellayani, 2021) Karishma Sebastian; Bindu, BThe investigation entitled “Fertigation studies in papaya (Carica papaya L.)” was carried out in Instructional Farm, College of Agriculture, Vellayani during the period 2018 – 2020 with the objectives to standardize the nutrient level for yield improvement through fertigation and foliar nutrition in papaya variety Surya and to study the postharvest management practices for extending the shelf life of papaya fruits. The experiment was undertaken in two parts. In part I, standardization of nutrient level for fertigation and foliar nutrition was carried out in RBD with 14 treatments replicated thrice. A combination of four fertigation doses of 75 %, 100 %, 125 % and 150 % RDF of N (304.89, 406.52, 508.15 and 609.78 g urea plant⁻¹ year⁻¹ respectively based on soil test data in 76 fertigation) and K (426.25, 568.33, 710.42 and 852.50 g MOP plant⁻¹ year⁻¹ respectively based on soil test data in 76 fertigation) and three foliar sprays (1.0 % 19:19:19 at bimonthly interval starting from 4 MAP to 16 MAP, 0.5% ZnSO4 + 0.3% borax at 4 th, 8th, 12th and 16th MAP and water spray at bimonthly interval starting from 4 MAP to 16 MAP) were compared with soil application of recommended dose of NPK (187:170:341 g NPK plant-1 year-1 based on soil test data) (control 1) and 187:170:341 g NPK plant-1 year-1 based on soil test data as organic manures as combination of FYM, poultry manure and vermicompost in the ratio of 2:1:1 (control 2). In control 2, additional requirement of P and K were met through the application of rock phosphate and potassium sulphate respectively. Organic manure (15 kg FYM plant-1 ) was given uniformly to all treatments as basal. Lime and rock phosphate (500g and 850g respectively based on soil test data) was applied uniformly for all treatments as basal except controls. Urea and Muriate of Potash (MOP) were used as fertilizer sources for fertigation and applied weekly from 1 MAP to 20 MAP. Application of different levels of fertigation and different foliar sprays had significant effect on growth, yield and quality of papaya. Growth parameters viz., plant height, stem girth and number of leaves were significantly higher in plants receiving 100 % RD of N and K through fertigation and foliar sprays of 1.0 % 19:19:19 (T4) at bimonthly interval starting from 6 MAP to 16 MAP. T4 also recorded highest leaf area index at 6, 12, 18 MAP and at final harvest, flowering at the shortest height, highest number of female plants and highest fruit set (86.27 %). However, application of 100 % RD of N and K through fertigation and foliar sprays of 0.5 % ZnSO4 and 0.3 % borax at 4 th, 8th, 12th and 16th MAP (T5) initiated earliness in flowering (142.67 days) and harvest (275.00 days). Treatments T4 and T5 were on par in fruit length, fruit girth, fruit volume, pulp percentage, flesh thickness and yield contributing characters like fruit weight, number of fruits per plant and yield per plant (38.30 kg plant⁻1 and 37.60 kg plant⁻1 respectively). Fruit quality parameters viz., TSS, carotenoids, ascorbic acid, total sugar, reducing sugar and non reducing sugar were found highest in T5. Fruits from T5 also registered longest shelf life (5.78 days) and highest mean sensory score for all parameters. Index leaf analysis at 6 MAP revealed highest nitrogen and potassium content of leaf in T10 (150 % RD of N and K through fertigation and foliar sprays of 1.0 % 19:19:19). Calcium, magnesium and sulphur content of leaves were highest in T5, whereas boron and zinc content were highest in T8 (125 % RD of N and K through fertigation and foliar sprays of 0.5 % ZnSO4 and 0.3 % borax). Highest nitrogen and potassium of fruits were observed in T12 (150 % RD of N and K through fertigation with water spray). Highest nitrogen content in soil was noticed in T11 (150 % RD of N and K through fertigation and foliar sprays of 0.5 % ZnSO4 and 0.3 % borax) and T10 witnessed highest potassium content. T4 and T5 were at par regarding B : C ratio (2.58 and 2.54 respectively). In part II of the investigation, postharvest management for extending shelf life of papaya was carried out with nine treatments replicated thrice. Different postharvest treatments given were precooling - hydro cooling (S1), surface sanitization with 150 ppm sodium hypochlorite (S2), external coating with 1% chitosan (S3), precooling followed by external coating with 1% chitosan (S4), packaging with ethylene scrubber 8% KMnO₄ (S5), precooling followed by packaging with ethylene scrubber 8% KMnO₄ (S6), precooling followed by external coating with 1% chitosan and packaging with ethylene scrubber 8% KMnO4 (S₇), hot water treatment followed by waxing with 6% carnauba wax and packaging with ethylene scrubber 8% KMnO₄ (S8) and control (S9). Papaya variety Surya was raised at Instructional Farm, Vellayani and fruits at fully mature green stage were harvested, subjected to different postharvest treatments and packaging was done in CFB boxes and stored under ambient conditions till the end of shelf life. Papaya fruits subjected to precooling followed by external coating with 1% chitosan and packaging with ethylene scrubber KMnO₄ (S7) recorded the longest shelf life of 9.67 days, which was at par with S8 (hot water treatment followed by waxing with 6% carnauba wax and packaging with ethylene scrubber KMnO₄). Physiological loss in weight, ion leakage, percentage disease index, bacterial and fungal count were significantly lowest in S7 and S8 after three days of storage. These treatments also recorded maximum total carotenoids, total soluble solids, total sugar, reducing sugar and minimum acidity after nine days of storage which indicated extended shelf life. Highest mean rank score for sensory attributes were also recorded in treatments S7 and S8 after nine days of storage. In conclusion, application of 100 % recommended dose of N and K (406.52 g urea plant⁻¹ year⁻¹ and 568.33 g plant⁻¹ year⁻¹ respectively) through weekly fertigation from one to 20 months after planting and foliar sprays of 0.5 % ZnSO4 + 0.3 % Borax at 4 th, 8th, 12th and 16th MAP, along with basal application of 850g rock phosphate and 15 kg FYM resulted in increased growth, yield and quality characters of papaya variety Surya with highest B: C ratio. Fruits at fully mature green stage when subjected to precooling followed by external coating with 1% chitosan and packaging with ethylene scrubber 8% KMnO₄ in CFB boxes exhibited a shelf life of 9.67 days in storage under ambient condition in papaya variety Surya.Item Response of papaya (Carica papaya L.) to major mineral nutrients(Department of Pomology and Floriculture, College of Agriculture , Vellayani, 2003) Bindu, B; Jayachandran Nair, C SAn experiment was conducted in the Department of Pomology and Floriculture, College of Agriculture, Vellayani during 2001-2002, to study the response of major plant nutrients viz., nitrogen, phosphorus and potassium on growth, yield and quality of papaya under Kerala conditions and to standardise the optimum dose of these nutrients. The experiment was conducted in 33 confounded factorial RBD, confounding NPK in replication 1 and Np2K2 in replication 2. The present study revealed that application of nitrogen, phosphorus and potassium increased plant height, girth and number of leaves. The highest plant height was obtained with the combined application of 200 g N, 300 g P and 500 g K plan' year-', while the highest plant girth was obtained with application of 250 g N, 300 g P and 500 g K. Combined application of 300 g N, 250 g P and 500 g K p lant' year-' resulted in the maximum number of leaves. Plants receiving a dose of nitrogen at 250 g, 300 g phosphorus and 500 g potassium plant" took the shortest time for flowering. Combined application of nitrogen at 250 g plant.", phosphorus at 250 g plant" and potassium at 500 g planr' considerably shortened the time for harvesting the first fruit. Fruit weight, number of fruits plant", yield planr' and papain yield increased by application of nitrogen, phosphorus and potassium. Application of 250 g N, 250 g P and 500 g K planr' year-' gave highest yield. Maximum fruit girth was obtained from 200 g N, 200 g P and 500 g K, whereas maximum fruit volume and pulp percentage was obtained from 250 g N, 250 g P and 500 g K. Levels of nitrogen and phosphorus tried had no significant influence on TSS and ascorbic acid content of fruits. Nitrogen at 200 g, phosphorus at 250 g planr' produced. fruits of low acidity, while potassium had no significant influence. The combination of 200 g nitrogen, 300 g phosphorus and 500 g potassium plane 1 year" increased carotenoids, total sugars, reducing sugars and organoleptic qualities of fruits. Most of the treatments had light yellow peel colour, orange pulp colour and firm flesh. Nitrogen at 200 g, phosphorus at 250 g and potassium at 500 g plant" was found to increase the shelf life of fruits. Application of nitrogen, phosphorus and potassium increased soil and leaf petiole content of the respective elements. Highest benefit: cost ratio was obtained from the combination of 250 g N, 250 g P and 500 g K I -I -I P ant year . Over all assessment indicated that application of N, P and K at the rate of 250 : 250 : 500 g plant" year-I in six equal splits was economically viable and improved growth, yield and quality of papaya.Item Bio-ecology and management of papaya mealybug on mulberry(Department of Agricultural Entomology, College of Agriculture, Vellayani, 2014) Rajan, V P; Krishnakumar, RItem Feasibility of puza zero energy cool chamber as low cost on-farm storage structure under Kerala condition(Department of post harvest technology, college of agriculture, Vellayani, 2019) Lekshmi, S G; Mini, CItem Organic nutrient management of papaya (Carica papaya L.)(Department of Pomology and Floriculture, College of Agriculture, Vellayani, 2018) Divya Hari; Bindu, B