Browsing by Author "Resmi Paul"

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    Induction of variation in vitro and field evaluation of somaclones in ginger (zingiber officinale rosc)
    (Department of Plantation Crops and Spices, College of Horticulture, Vellanikkara, 2006) Resmi Paul; Shylaja, M R
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    Micronutrients and biostimulants for crop management in marigold (Tagetes erecta L.)
    (Department of Floriculture and Landscaping, College of Agriculture, Vellanikkara, 2025) Aparna, M Rajeev; Resmi Paul
    Investigations on “Micronutrients and biostimulants for crop management in marigold (Tagetes erecta L.)” was undertaken at the Department of Floriculture and Landscaping, College of Agriculture, Vellanikkara during 2024 to 2025. Objectives of the study were to evaluate the influence of micronutrients, biostimulants, and plant growth promoting rhizobacteria (PGPR) on the growth, yield, and quality attributes of African marigold. Studies were carried out in the hybrid Royal Orange. The experiment was laid out in a randomized block design comprising of ten treatments with three replications each, involving combined application of recommended dose of fertilizers (RDF), boron (1 kg ha⁻¹), varying concentrations of humic acid (1%, 3%, and 5%), salicylic acid (50, 100, and 150 ppm), and PGPR Mix I and II (2% and 5%). Treatments were applied through soil application, foliar spray, soil drenching, and root dipping at different growth stages of the plants. Vegetative, floral, and biochemical parameters of the plants and soil nutrient characteristics of the experimental plot were studied. Significant variations among treatments were observed for all the traits studied except for the shelf life of flowers. Among the treatments, application of 5% humic acid along with RDF and boron (T5) recorded significant improvement in plant height (46.25 cm), plant spread (29.29 cm), number of branches per plant (15.67), and leaf count (15.5 per branch). This treatment also resulted in the highest fresh (464 g and 64 g respectively) and dry (95 g and 29 g respectively) shoot and root biomass, indicating enhanced nutrient absorption and root development. The same treatment (T5) also advanced the onset of flowering, with the earliest bud emergence (31.67 days) and 50% flowering (31.83 days), while the control treatment (RDF alone) showed delayed flowering (41.08 days). Floral attributes such as number of flowers per plant (18.67), flower diameter (6.03 cm), individual flower weight (8.8 g), and flower yield per plant (159.93 g) were also maximized in T5 (RDF + boron + 5% humic acid), followed by treatments with RDF + boron + PGPR (T9 and T10) and RDF + boron + salicylic acid (150 ppm) (T8). The duration of flowering (71.08 days) and field life of flowers (7.58 days) were prolonged under T5 (RDF + boron + 5% humic acid), reflecting improved physiological activity. Biochemical analysis revealed that treatments consisting of RDF + boron + salicylic acid and RDF + boron + PGPR improved biochemical composition of leaves and flowers. The treatment with RDF + boron + 150 ppm salicylic acid (T8) exhibited highest chlorophyll a (1.313 mg g⁻¹ FW), chlorophyll b (1.295 mg g⁻¹ FW), and total chlorophyll (2.61 mg g⁻¹ FW), suggesting improved photosynthetic efficiency. PGPR Mix II (5%), along with RDF and boron (T10), significantly increased phenolic (21.78 mg GAE/g and 54.23 mg GAE/g respectively) and flavonoid (0.307 mg QE/g and 4.51 mg QE/g respectively) contents in leaves and flowers, and carotenoid content (0.051 mg/g FW) in flowers, indicating higher antioxidant potential and stress tolerance. Nutrient uptake studies indicated that plants which received RDF + boron + 5% humic acid (T5) exhibited superior uptake of nitrogen (3.04 g plant⁻¹), phosphorus (0.238 g plant⁻¹), iron (0.219 g plant⁻¹), and zinc (0.029 g plant⁻¹). Potassium uptake was not significantly correlated with yield, suggesting that other nutrients played a more decisive role in flower production. Soil analysis after harvest of flowers showed improved macronutrient and micronutrient availability in plots receiving RDF + boron + PGPR and RDF + boron + biostimulants. Correlation studies demonstrated that yield per plant had a significant positive association with key vegetative and floral traits such as plant spread, number of branches and flowers, flower diameter and weight, duration of flowering, and total chlorophyll content, while being negatively correlated with the number of days to bud emergence and 50% flowering. Similarly, flower yield showed significant positive correlations with the uptake of nitrogen, phosphorus, iron, manganese, zinc, and boron, underscoring the role of balanced nutrition in the enhancement of productivity. Combined use of micronutrients and biostimulants improved growth, yield and quality attributes of African marigold. Integrated application of RDF + boron + humic acid (5%) enhanced the overall growth, yield and floral characteristics of African marigold. The use of RDF + boron + salicylic acid proved beneficial in enhancing chlorophyll content, flower longevity, and stress resilience, whereas RDF + boron + PGPR combinations improved secondary metabolite accumulation, contributing to superior flower colour and quality. Combinations and concentrations of micronutrients and biostimulants along with RDF identified in the present study could be utilized in further investigations.
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    Parasexual hybridization of piper nigrum and piper colubrinum through protoplast fusion
    (Department of Plantation Crops And Spices,College of Horticulture, Vellanikkara, 2000) Resmi Paul; Rajendran, P C
    Black pepper is the most important export oriented commodity and foreign exchange earner among the Indian spices. Ravages due to diseases, particularly the most devastating Phytophthora foot rot caused by Phytophthora capsici is one of the major constraints in the production of black pepper all over the world. Piper colubrinum, a wild relative of black pepper is found to be immune to foot rot disease. Non – existence of cultivar level tolerance or resistance against foot rot disease in black pepper necessitated the incorporation of incompatible wild relatives through parasexual hybridization. This study was undertaken in the Department of Plantation Crops and Spices and the Plant Tissue Culture laboratory of the Centre for Plant Biotechnology and Molecular Biology, College of Horticulture, Vellanikkara between September 1998 to April 2000. The cultures of P. nigrum and P. colubrinum were initiated in test tubes and were maintained at 26 + 20C temperature and 60 to 80 per cent humidity. The green leaves excised from axenic cultures of both the species were treated with cell wall degrading enzymes, cellulose and pectinase maintained at proper osmotic concentration. In P. nigrum maximum yield was observed at 1.4 per cent cellulose and 0.34 per cent pectinase. Cellulase and pexctinase at a concentration of 1.0 per cent and 0.217 per cent respectively recorded highest yield in P. colubrinum. In both the species 0.6 M osmoticum was found to be optimum to maintain the osmotic potential of the isolation solution. Highest yield of protoplasts was recorded in both the species during 21 h of digestion. Filtration-centrifugation technique was found to be superior in purifying the Piper protoplasts compared to the sucrose floatation method. Centrifugation at 1000 rpm for three minutes was found to be best for purifying P. nigrum protoplasts. For purifying P. colubrimum protoplasts, 600 rpm for three minutes was found to be optimum. Highest viability was noticed at 0.55 M and 0.65 M osmoticum in 1.0 per cent cellulose and 0.28 per cent pectinase during 21 h of digestion in P. nigrum. In P. colubrinum, maximum viability was observed at 0.4 M osmoticum in the enzyme mixture 1.0 per cent Cellulase and 0.186 per cent Pectinase during 18 h of incubation. Protoplasts of both the species when cultured on modified MS medium formed no cell wall and have not undergone any division. A age of the cultures advanced, proptoplast viability decreased in P. nigrum and P. colubrinum. All the protoplasts died by the second week in both the species. The protoplasts of both the species were heterogenous in terms of size. Fusion of the protoplasts was not observed after PEG treatment in the present study.
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    Vegetative propagation in orange jasmine (Murraya paniculata L. Jack)
    (Department of Floriculture and Landscaping, College of Agriculture, Vellanikkara, 2025-01-25) Yarrakula Venugopal; Resmi Paul
    Murraya paniculata L. Jack, commonly known as orange jasmine, belongs to the family Rutaceae. This versatile plant is highly valued for its ornamental appeal and various practical applications. Its leaves and stems are widely used as cut foliage in floral arrangements, bouquets, wreaths, and interior decorations. Fully bloomed trees, adorned with fragrant white flowers, make it striking specimen plant in gardens. Orange jasmine can be propagated through seeds, but sexually propagated plants take a long time to flower, and seeds are not available throughout the year. Vegetative propagation through cuttings is challenging due to their difficulty in rooting, creating a need for more effective propagation methods. With rising demand in the cut foliage industry, commercial cultivation of orange jasmine has increased, further emphasizing the need for accessible planting materials. Currently, most planting materials are sourced from specific centers, such as Rajahmundry in Andhra Pradesh, which adds to the cultivation cost. To address these challenges, the present study entitled “Vegetative propagation in orange jasmine (Murraya paniculata L. Jack)” was carried out at the Department of Floriculture and Landscaping during 2022 2024. The study comprised of three experiments viz., standardization of propagation by cuttings, standardization of media for propagation of cuttings and standardization of air layering. In the first experiment, type of cutting and growth regulator treatment for propagation of orange jasmine was standardised. Softwood and semi hardwood cuttings were subjected to different treatments like coconut water (10 minutes) and various concentrations of growth regulators (IBA and NAA alone and combinations of IBA and NAA) for one minute during June 2024. Cuttings were then planted in polybags filled with soil, coir pith and FYM (2:1:1) and kept for rooting in side protected rain shelter. Softwood cuttings treated with 1000 ppm IBA exhibited increased sprouting (72.22 %), shoot length (8.52 cm), leaf number (4.56), rooting percentage (72.22 %), root number (15), root length (21.45 cm), root volume (2.91 cm3), fresh root weight (1.18 g) and dry root weight (0.157 g) at 120 days after planting. Softwood cuttings treated with 2000 ppm IBA exhibited early sprouting (8.67 days). Total phenol and flavonoid content in the basal part of the cuttings was lower in softwood cuttings treated with 1000 ppm IBA at 30 (phenol: 4.13 mg/g FW, flavonoid: 2.16 mg/g FW) and 45 (phenol: 3.45 mg/g FW, flavonoid: 1.73 mg/g FW) days after planting. Histological and external morphological observations revealed that adventitious roots of M. paniculata originated from the cambial cells of the xylem. These roots extended outwards through the phloem, schlerenchyma, cortex, epidermis, and callus tissue and emerged out. Unlike other species, no white callus tissue covering the base of the cuttings was observed in orange jasmine. In the second experiment, best treatment selected from the first experiment i.e. softwood cuttings treated with 1000 ppm IBA for one minute were planted in different rooting media such as control (soil: coir pith: FYM- 2:1:1), sand, sand + coir pith (1:1), sand + coir pith + soil (1:1:1), coir pith + vermiculite + perlite (3:1:1), coir pith + FYM (1:1) + VAM (10 g/ polybag) + Azospirillum (10 g/ polybag). Cuttings planted in coir pith + FYM (1:1) + VAM (10 g/ polybag) + Azospirillum (10 g/ polybag) performed well compared to other treatment combinations used in the study by recording minimum days for sprouting (9.50), maximum shoot length (6.24 cm), number of leaves (3.67), rooting percentage (66.67 %), number of roots (12.83), root length (19.94 cm), root volume (2.81 cm3), fresh weight of roots (0.99 g) and dry weight of roots (0.094 g) at three months after planting. When B:C ratio of two treatments (T1 and T6) when compared, T1 recorded higher B:C ratio (4.3) compared to T6 (2.9) and was found more economically viable. In the third experiment on air layering, after removal of bark from mature shoots, the girdled portion was treated with different plant growth regulators viz., IBA, IAA and NAA (1000 and 2000 ppm) and subjected to air layering during July 2024. Sphagnum moss was used as media for rooting purpose. Among the different treatments, IBA 2000 ppm performed well compared to other treatments tried in the study by recording less number of days for root initiation (27.67 days), maximum root length (8.26 cm), number of roots (62.33), root volume (2.41 cm3), minimum days for separation of air layers from the mother plant (56.67days) and higher survival percentage (76.67%) of the layers in the nursery. The present study revealed that softwood cuttings are better than semi hardwood cuttings for propagation of orange jasmine. Softwood cuttings treated with IBA 1000 ppm for one minute recorded superior growth parameters compared to other treatments. Suitable growing media identified for propagation of orange jasmine was coir pith + FYM (1:1) + VAM (10 g/ polybag) + Azospirillum (10 g/ polybag). Application of IBA 2000 ppm in the girdled portion of mature shoots of orange jasmine was found superior for air layering due to their better growth parameters