Browsing by Author "Sheena, A"

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    Characterization and compatibility studies in waterlily (Nymphaea spp.)
    (Department of Floriculture and Landscaping, College of Agriculture , Vellayani, 2024-02-27) Aiswarya, P; Sheena, A
    The research programme entitled ‘Characterization and compatibility studies in waterlily (Nymphaea spp.)’ was carried out in the Department of Floriculture and Landscaping, College of Agriculture, Vellayani, Thiruvananthapuram during the period 2022-2023 to evaluate the performance of thirty waterlily varieties based on growth, flowering and floral attributes. Out of the thirty waterlily varieties, flowering was observed in 28 varieties viz., Micrantha, Chompu, Taweekan, Bull’s Eye, Hilary, Doris Holt, Carla Sonshine, Siam Jasmine, Wanvisa, Mexicana, King of Siam, Blue Whistle, Purple Joy, Dauben, Poonsub, Clyde Ikins, Virginalis, Peach Blow, Islamorada, Siam Pink, Supranee Pink, Jalueang Sub, Tropic Sunset, Miami Rose, Colorado, Almost Black, Paranee, Siam Amber, Perry’s Baby Red. The flower of Nymphaea exhibited strong protogyny, wherein they expressed stigma receptivity on the initial day, followed by the release of pollen on the subsequent two days. The analysis of variance revealed significant differences among the 21 genotypes for all the floral characters except for days to appearance of flower bud and days to flower opening. Significant varietal differences were observed among the thirty genotypes with respect to the vegetative characters. Among the vegetative characters, the highest PCV was recorded for number of leaves (30.04 per cent) and the lowest for the longevity of the leaf (16.59 per cent). The number of leaves exhibited the highest GCV (27.31 per cent) and the lowest for the number of days from visual observation to full expansion of leaf lamina (8.03 per cent). Maximum PCV and GCV were observed for number of leaves per plant (PCV 30.04% and GCV 27.31%) followed by length of lamina (PCV 20.71% and GCV 20.53%) and minimum PCV and GCV for longevity of leaves (16.59 and 8.36 per cent respectively). Among the floral characters, number of petals recorded the highest PCV (74.25%) and GCV (74.49%) followed by width of petal with PCV (27.42%) and GCV (27.61%). The minimum PCV and GCV were observed for the length of flower bud (7.14 per cent and 7.47 per cent). The genotypes were grouped into four clusters based on vegetative quantitative characters (length of lamina, width of lamina, number of leaves per plant, longevity of leaves, petiole diameter and number of days from visual appearance to full expansion of leaf lamina). Cluster 1 comprised of 13 genotypes, cluster 2 comprised of 15 genotypes, cluster 3 and 4 comprised of 1 genotype each. Maximum inter cluster distance with respect to vegetative characters was observed between C1 and C 3 which is 18.48 while minimum distance between C 2 and C 4 which is 7.94. The genotypes were grouped into five clusters based on floral quantitative characters (length of flower bud, flower diameter, length of sepal, breadth of sepal, number of petals, length of petal and breadth of petal). The Cluster 1 composed of 3 genotypes, cluster 2 composed of 5 genotypes, cluster 3 composed of 7 genotypes, cluster 4 composed of 4 genotypes and cluster 5 composed of 2 genotypes. Maximum inter cluster distance among the floral characters was observed between the clusters C2 and C3 which is 75.19 and minimum distance between C1 and C3 which is 7.36. The greater the distance between two clusters the greater is the divergence between genotypes belonging to the two clusters and vice versa. All the genotypes exhibited four consecutive days of anthesis. The anthesis timings of waterlily flowers were affected by environmental factors. Cloudy and rainy weather conditions led to delayed flower opening and early flower closing. Significant variations were observed in the number and length of stamens in all the varieties, except in King of Siam and Taweekan where stamen production was not observed. The majority of the studied pollen displayed a prolate spheroidal shape and fell within the medium-sized category. Highest pollen fertility was observed in the varieties Doris Holt (84%) followed by Peach Blow (73%), Hilary (68%), Micrantha (65%), and Bull’s Eye (48%) and these varieties were selected as the male parent for the compatibility study. Based on preliminary hybridization, maximum stigma receptivity was observed for the varieties Poonsub, Wanvisa, Siam Amber, Siam Jasmine and Blue Whistle and these varieties were selected as the female parent for the compatibility study. Maximum percentage of fruit set were observed when Siam Amber x Doris Holt (100%) followed by Poonsub x Micrantha (80%) and Poonsub x Wanvisa (80%). The fruit weight and seed size of Siam Amber x Doris Holt was larger compared to other varieties. The hybrid seeds took eight days for germination and they flowered in 25 to 29 days. The hybrid plants are in flowering, near flowering and pre flowering stages. Vegetative and floral characters of the hybrids that flowered when compared with their parents, revealed variations in the parameters studied. The hybrids obtained in the present study can be further assessed for floral attributes and selected for cultivation
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    Ex vitro establishment of gladiolus (Gladiolus grandiflorus L.)
    (Department of Pomology and Floriculture, College of Agriculture, Vellayani, 2004) Sheena, A; Sheela, V L
    Studies were conducted to standardize ex vitro establishment techniques in Gladiolus grandiflorus L. variety Vinks Glory during 2002-2004 in the Department of Pomology and Floriculture, College of Agriculture, Vellayani. The effects of various potting media (sand, soilrite, sand: soil, sand: soil: coirpith, sand: soil: leaf mould), triazole (0, 4 and 8 mg/l), mycorrhizae (Glomus fasciculatum and Glomus monosporum) and height of potting media in the container (4 and 6 cm) on ex vitro establishment of the micropropagated plantlets were studied. Among the different potting media used for ex vitro establishment, soilrite recorded higher survival rates of 86.11 and 80.55 per cent after the first and second fortnight respectively. Triazole application improved the survival rate over non-treated plants. Triazole at 4 and 8 mg/l concentrations recorded 54.16 and 55.83 per cent survival respectively after one month of planting. The two mycorrhizal fungi tried in the study exerted differential effect on survival. Colonization of the roots by mycorrhizal inoculation was found to be high and this enhanced the survival rate of plantlets. Leaf number and plant height was found to be affected by triazole application. Triazole treated plants exhibited a decrease in number of leaves and a reduced plant height due to its growth retarding action which in turn resulted in reduced leaf area index. Triazole application delayed leaf production of plants due to inhibition of leaf expansion. Fresh weight, dry weight, CGR and RGR were found to be high in treatments with triazole application. Growth of mycorrhizal fungi was affected by different potting media. But triazole treatment did not affect the colonization of AMF. Among the two mycorrhizal fungi, Glomus fasciculatum inoculated plants exhibited higher plant height, increased number of roots, delayed emergence of leaf and low stomatal conductance. A decrease in stomatal conductance observed during the later stages of planting out indicate the acclimatization of the plantlets to the ex vitro conditions. Potting media, triazole, mycorrhizae and their interactions affected the stomatal conductance significantly. Height of potting media in the container did not influence the survival and growth parameters. The estimated cost of hardened plants ranged from Rs. 4.50 to 5.25. Eventhough the cost is higher than that of conventional propagation method, this can satisfy the need for large scale production of disease free planting material.
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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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    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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    Performance analysis and combining ability studies in anthurium cultivars
    (Department of Pomology and Floriculture, College of Agriculture, Vellayani, 2015) Sheena, A; Sabina George, T