PG Thesis

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Subject: search.filters.subject.Morphological characterization

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    Morphological characterization and cross compatibility studies in Hibiscus rosa sinensis
    (Department of Floriculture and Landscaping, College of Agriculture , Vellayani, 2025-01-30) Prejith Raj, S J.; Sheena, A
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    Morphological and molecular characterization of Cattleya hybrids
    (Deparment of Floriculture and Landscaping, College of Agriculture, Vellayani, 2023-04-17) Liji Viswanathan.; Sheena, A
    The research programme entitled ‘Morphological and molecular characterization of Cattleya hybrids’ was carried out in the Department of Floriculture and Landscaping, College of Agriculture, Vellayani, Thiruvananthapuram during the period 2021-2022 to evaluate the performance of twelve Cattleya hybrids based on growth and flowering attributes and to characterize them using morphological descriptors and molecular markers. The analysis of variance revealed significant differences in 12 genotypes for all of the studied morphological characters, with the exception of plant height, such as the number of shoots per plant, number of leaves per pseudobulb, length and width of the largest leaf, and number of days from leaf emergence to maturity. Out of the 12 Cattleya hybrids, flowering was observed in ten hybrids viz., Rth.Burana Beauty, Rlc.Taichung Beauty, Rlc.Mahina Yahiro, Rlc.Irene Dopkin, C.Aurantiaca x Netrasiri Beauty, Rlc.Petch Wangnam Khiew, Rlc.Morning Stars, Rlc. Haadyayi Delight x Mary Song, Rlc.Memoria Anna Balmores and C.Tipo during the experiment. Significant varietal differences were observed among the ten genotypes with respect to the floral characters studied. Variance component analysis revealed that highest PCV and GCV was observed for number of shoots per plant and minimum for plant height among morphological characters. Maximum variability both at the phenotypic and genotypic level was observed for the inflorescence number per pseudobulb followed by flower number per peduncle among floral characters High heritability values were recorded for the floral characters viz., length and width of petal and dorsal sepal width followed by flower length. High heritability with genetic advance was observed for petal and sepal width followed by inflorescence number per pseudobulb. 92 Flower width, length and width of petal, sepal and lip had significant positive genotypic correlation with length and width of the largest leaf. Flower number per peduncle exhibited positive correlation with plant height and number of leaves per pseudobulb showed negative correlation with flower width, petal, sepal and lip length and width. Plant height had significant positive phenotypic correlation with length and width of the petal and length of the largest leaf. Flower number per peduncle showed a significant negative correlation with flower length and width. The length of flower had significant positive correlation with width of the flower, which is an important attribute of cut flower selection. Low values of environmental correlation coefficient due to environmental effect were estimated for most of the characters studied. The genetic diversity among the genotypes was studied using ‘Average method’ and ‘Euclidean Distance measures’. The genotypes were clustered into three groups based on morphological and floral quantitative characters. Maximum inter cluster distance was observed between the clusters C2 and C3 and minimum distance between C1 and C3. So selection of parents from the clusters C2 and C3 will be very effective in hybridization. Four hybrids viz., Rlc.Morning Stars, Rlc. Haadyayi Delight x Mary Song, Rlc.Memoria Anna Balmores and C. Tipo recorded high scores based on scoring given by DUS guidelines. Molecular characterization of 12 Cattleya genotypes were carried out using ISSR primers. DNA yield varied from 0.776 ng/µl to 27 ng/µl. Out of the 97 amplicons obtained, 96 were polymorphic and one was monomorphic.The twelve genotypes were divided into four clusters at similarity coefficient of 0.65. The clusters formed by morphological and molecular characterization grouped the genotypes C. Chocolate Drops Volcano Queen and C.Aurantiaca x Netrasiri 93 Beauty in the same cluster. The genotypes in the various clusters were nearly identical in terms of morphology and genetics. High petal and sepal width which are good floral attributes was observed for the genotype Rlc.Petch Wangnam Khiew. C. Tipo was floriferous (25 flowers per plant per year) followed by C. Aurantiaca x Netrasiri Beauty (20 flowers per plant per year) compared to the other hybrids. All other hybrids exhibited seasonal variation in flower production. So Rlc.Petch Wangnam Khiew, C. Tipo and C. Aurantiaca x Netrasiri Beauty may be selected as parental genotypes with good floral attributes.
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    Characterization of kuttiattoor mango (Mangifera indica L.) Cultivar of Kannur district, Kerala
    (Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2017) Reshma Reghu; Elsy, C R
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    Evaluation of selected cocoa (Theobroma cacao L.) hybrids bred for quality
    (Department of Plantation Crops and Spices,College of Horticulture, Vellanikkara, 2016) Ajmal, P M; Suma, B
    Cocoa (Theobroma cacao L.) is an important beverage crop belonging to the family Malvaceae. The most important economic part of cocoa is the optimally fermented and dried beans, which is the only source of chocolate flavour. Consumers have shown an increased interest for high quality dark chocolate containing a higher percentage of cocoa. Therefore, the quality of cocoa beans has a great importance while considering the market value. The genetic makeup of an individual cocoa genotype influences flavour, quality and intensity of chocolate.Cocoa is mainly classified into three types, namely Criollo, Forastero and Trinitario. The Criollo types provide fine flavour chocolate.
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    Characterization of betel vine (piper betle L) types of Malappuram district
    (Department of Plant Breeding and Genetics, College of Horticulture, Vellanikkara, 2012) Preethy, T T; Elsy, C R
    The present investigation on “Characterization of betel vine (Piper betle L.) types of Malappuram district” was carried out at the Department of Plant Breeding and Genetics, College of Horticulture, KAU, Vellanikkara and farmer’s field in Malappuram district during 2013 – 2014 aiming to study the diversity of betel vine types in Tirur and nearby areas of Malappuram district and to characterize the types based on morphological and biochemical features. Puthukodi, Chelan, Karinadan and Nadan were the betel vine cultivars recorded from Malappuram District. Puthukodi and Nadan were the most common cultivars whereas Chelan and Karinadan were the cultivars conserved by few farmers. Morphological characterization revealed distinctness of Karinadan and Chelan from other cultivars. Karinadan had dark green leaves with even leaf margin, short petiole, mostly ovate lanceolate leaf lamina, high brittleness and medium pungency. Leaf characters including leaf length, leaf width, leaf area and leaf weight per unit area were comparatively high in this cultivar. Orthotropic shoots of this cultivar showed uniform purple – green color. It produced hanging lateral branches. The plant growth parameters like plant height, total number of leaves, number of lateral branches and number of leaves per lateral branch were significantly low in this cultivar. On the other hand, Chelan had light green leaves with wavy leaf margin, long petiole, ovate leaf lamina and round leaf base. Leaf characters including leaf length, leaf width, leaf area and leaf weight per unit area and brittleness were significantly low in this cultivar leading to low market preference. In this cultivar, internodes of orthotropic shoots showed light green colour with purple tinge. Lateral branches of Chelan were semierect in nature. The plant growth parameters like plant height, total number of leaves, number of lateral branches and number of leaves per lateral branch were significantly high in this cultivar, resulting in higher number of leaves per plant. Nadan, Puthukodi and Muvattupuzha Local cultivars had green leaves with even margin and medium brittleness. Puthukodi recorded maximum leaf weight per unit area and optimum leaf parameters, making it as the most preferred cultivar in Malappuram district. Profuse flowering was observed in all cultivars during the study period. Chelan was identified as male cultivar and all others were female cultivars. Spikes produced on Chelan were long, slender with short peduncle. Female cultivars produced medium lengthy spikes having medium diameter. Spikes were axillary and opposite to leaf. Sessile naked florets were compactly arranged on the inflorescence axis. A bract subtended each floret, both in male and female spikes. Female spike was very distinguishable with the presence of 6 - 9 white coloured sessile stigmatic lobes on each floret. Male spikes were yellow in color and at the stage of anthesis, two black stamens protruded from each floret protruded. Essential oil content was maximum in Muvattupuha Local, a cultivar with high pungency and it was low in Chelan. GC studies revealed that, eugenol was the major component of essential oil in all cultivars with high content (20.80 per cent) in Chelan. Possible compounds identified from the chromatograms of oil from different cultivars were hydroxychavicol, β caryophyllene and 5-(2-propenyl)-1, 3- benzodioxole. Karinadan was rich in biochemical constituents whereas Chelan was significantly low in biochemical constituents. Puthukodi with optimum leaf characters recorded medium pungency. Studies on genetic parameters revealed that most of the characters were less affected by environmental factors. Many of the characters under study showed high heritability with high genetic gain, indicating additive gene effects and selection must be effective. Correlation studies showed that the highest significant positive genotypic correlation of total number of leaves was with number of leaves per lateral branch followed by plant height and number of lateral branches. Number of leaves per lateral branch showed highest positive direct effect and all other characters showed negative direct effect on total number of leaves.