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2020 - 20223
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Subject: Floriculture and Landscaping × End date: 2023 × Start date: 2020 × Thesis Type: Ph.D ×
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Now showing 1 - 3 of 3
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    Combining ability and heterosis studies in a diallel cross of periwinkle (Catharanthus roseus L.)
    (Punjab Agricultural University, Ludhiana, 2022) Bolagam Ravikumar; Dhatt, K. K.
    The current investigation entitled "Combining ability and heterosis studies in a diallel cross of periwinkle (Catharanthus roseus L.)" was investigated at the Floriculture Research Farm of Punjab Agricultural University, Ludhiana during the years 2019 to 2022. Six inbred lines of periwinkle namely P1 (Vi-15-1), P2 (Vi-13-2), P3 (Vi-16), P4 (Vi-15-2), P5 (Vi-29) and P6 (Vi-14-3) were crossed in full-diallel fashion with an objective of identifying superior cross-combinations for high specific combining ability and qualitative traits and determine the inheritance of flower colour and size. The six inbred lines and their thirty cross combinations were evaluated for plant height, plant spread, number of primary branches per plant, leaf length, leaf breadth, internode length, corolla tube length, days to flowering, duration of flowering, number of flowers per plant, flower diameter, follicle length and number of seeds per follicle in Randomized Block Design and replicated thrice. Analysis of variance was highly significant for all the vegetative and flowering characters indicating presence of genetic variability in the genotypes. The analysis of variance for combining ability was highly significant for growth and flowering characters indicated presence of both additive and non-additive gene actions. The parents P5 (Vi-29) and P1 (Vi-15-1) were recorded preferable GCA effects for most of the traits. These were considered as good general combiners for crossing programmes. The cross combination of Vi-13-2 × Vi-29 had significant positive maximum SCA effects for plant height, plant spread and number of primary branches per plant. The follicle length and number of seeds per follicle were recorded highly significant positive SCA values in the combination of Vi-29 × Vi-14-3. The high significant positive reciprocal effects were recorded for plant height, leaf breadth, number of flowers per plant and number of seeds for follicle in the cross combination of Vi-14-3 × Vi-29. The plant spread, duration of flowering and corolla tube length were shown high significant positive reciprocal results in cross combination of Vi-14-3 × Vi-13-2. The highly significant positive heterobeltiosis was present in the progenies of Vi-29 × Vi-14-3, Vi-13-2 × Vi-29 and Vi-15-1 × Vi-14-3 for most of the studied traits. High to moderate values for phenotypic and genotypic coefficients of variation were shown for majority of the studied characters, recapitulate the presence of variability. The range of phenotypic and genotypic coefficient of variations among the parental lines was 5.35-34.41% and 3.96-34.02%, respectively. The PCV and GCV was 4.14-25.49% and 4.01-24.94% for the cross combinations, respectively. The heritability varied from 46.74-97.77% and 50.62-98.73% for the parental lines and cross combinations, respectively. It indicated that the traits were highly heritable to following generations. The average genetic advance as per cent mean was observed as 8.00-50.21% and 6.03-69.29% among the inbred lines and cross combinations, respectively. The flower colour and size were segregated with 3:1 (monohybrid), 9:3:4 (supplementary gene action), 9:6:1 (polymeric gene action) and 9:3:3:1 (typical dihybrid) in F2 generation of fifteen selected crosses from diallel crosses.
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    Salt stress induced morpho-physiological, biochemical and anatomical changes in ornamental tree species
    (Punjab Agricultural University, Ludhiana, 2022) Nagar, Kamal Kishor; Dubey, R. K.
    The present investigations entitled “Salt stress induced morpho-physiological, biochemical and anatomical changes in ornamental tree species” were undertaken at Landscape Nursery, Department of Floriculture and Landscaping, Punjab Agricultural University, Ludhiana, during 202022 to screen salinity tolerant ornamental tree species for green of salt affected land. One year old seedlings of fifteen tree species were grown in 10” earthen pots containing soil: FYM (2:1) during first week of February 2020. After one month of transplanting, different concentrations of NaCl viz., 0, 50, 100, 150 and 200 mM were given with irrigation water from March 2020 to January 2022. All the parameters were recorded at four-month interval. The salt treatments significantly (p<0.05) affected the morpho-physiological, biochemical and anatomical parameters of ornamental tree species. On the basis of investigations, the tree species were categorized as salt tolerant and salt sensitive. Salt tolerant trees include Delonix regia, Acacia auriculiformis, Cassia fistula, Pongamia pinnata, Plumeria alba, Mimuspos elengi, Butea monosperma, Callistemon lanceolatus and Erythrina variegata whereas, salt sensitive include Jacaranda mimosifolia, Bauhinia purpurea, Koelreutaria paniculata, Millettia ovalifolia, Lagerstromia speciosa and Putranjiva roxburghii. The growth parameters slightly increased or maintained in tolerant trees, whereas in salt sensitive trees, growth parameters decreased with an increase in salt concentration during January 2021 and January 2022. The maximum per cent increase in number of branches (19.02%), survival percent (94.36%), reducing sugar (16.94%) at the concentration of (100 mM NaCl) and upper epidermis thickness (45 µm), palisade thickness (128.05 µm), lower epidermis thickness (42 µm), palisade cell length (70.23 µm), palisade cell diameter (32 µm), intercellular space (16.4%) was recorded in C. Lanceolatus at 200 mM NaCl, whereas, during May 2020 to January 2022, minimum per cent decrease in fresh and dry weight of leaves (26.50%), fresh and dry weight of root (26.78 %) and fresh and dry weight of stem (11.54%), was also observed in the same species at 200 mM NaCl. During May 2020 to January 2022, the maximum per cent increase plant height (21.23%), lea area (20.94%), phenol (33.33%) and carotenoid (8.91%) was recorded in E. variegata. In C. fistula tree species maximum percent increase number of leaves (10.23%), plant spread (6.36%), protein (8.33%) and starch (17.33%) at the concentration of 50 mM NaCl. RLWC (5.28 %) and proline (12%) was found in P. alba at 200 mM NaCl. The maximum total chlorophyll, carotenoid, proteins, RLWC, starch, reducing sugar and minimum proline and soluble sugars was observed during rainy season. Osmolyte concentration was more during January. As the level of NaCl in soil increased, EC also increased. It is difficult to maintain the EC during rainy season as due to dilution effect as well as leaching of salts, consequently resulted in reduced level of EC. On the basis of morpho-physiological, biochemical and anatomical parameters during the 1st and 2nd year of the experiment, tree species were classified as salt tolerant and susceptible. From these, plants highly salt tolerant and the salt susceptible tree species were planted at PAU regional research station, Bathinda. The maximum increase in plant height (4.08 m) in C. fistula, Number of branches per plant (12.0) C. lanceolatus, Stem girth (150.17 mm) A. auriculiformis, Plant spread (1.92 m) C. lanceolatus and survival percentage (100 %) in C. lanceolatus, Pongamia pinnata and C. fistula was observed in saline water irrigated tree species.
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    Studies on genetic diversity in chrysanthemum (Chrysanthemum morifolium Ramat.) through hybridization, cytological and molecular approaches for commercial traits
    (Punjab Agricultural University, Ludhiana, 2020) Anu Bala; Madhu Bala
    The present investigations entitled “Studies on genetic diversity in chrysanthemum (Chrysanthemum morifolium Ramat.) through hybridization, cytological and molecular approaches for commercial traits” were undertaken at Department of Floriculture and Landscaping, Department of Plant Breeding and Genetics and Fruit Molecular Biotechnology Lab in School of Agricultural Biotechnology, Punjab Agricultural University, Ludhiana, during 2016-19. The study consisted of genetic diversity analysis of diverse genotypes of chrysanthemum through cytological, molecular studies and hybridization for commercial traits. Thirty chrysanthemum genotypes were selected from chrysanthemum germplasm maintained at PAU, Ludhiana for cytological studies. Young flower buds were used for preparation of slides and a range of ploidy level 2n=52-116 recorded among all selected chrysanthemum cultivars. In molecular characterization SSR markers were used to study genetic diversity of thirty chrysanthemum genotypes. Total 17 SSR‟s were selected and among these 15 markers exhibited polymorphism and remaining two were monomorphic. Fifteen polymorphic markers demonstrated relatively high level of polymorphism as out of total 53 alleles produced, 47 were polymorphic showing 92.22 % polymorphism. Genotypes were clustered into two main clusters based on the variability of 15 polymorphic SSR markers. In hybridization twenty-one crosses were made between cultivars belonging to early and main season group. Among twenty-one crosses seed set was recorded in sixteen crosses and germination per cent was observed in fourteen crosses only. Maximum number of seeds per flower head were found in cross Ratlam Selection x Reagan Emperor (11.00), highest seed germination percentage (40.00 %) was recorded in cross between Basanti x Reagan Emperor and seedling vigour found highest (60.00) in cross between Basanti x Reagan Emperor. Hybrids developed from inter crossing of chrysanthemum genotypes were evaluated for various morphological characters and showed variation with respect to flower colour and flower type can be used for different purposes like for pot culture, exhibition purpose and for loose flower production etc. From the effective positive response in terms of various investigations under study, it can be concluded that chromosomal and molecular study helped to estimate genetic diversity which is the most essential pre-requisite as it plays an important role in developing new and novel desired forms through breeding and selection. Polyploidy found could be further helpful for breeding programmes and new cultivars could be developed by addition or deletion of chromosomes in cultivars with known ploidy level. Hybridization helps in development of segregating population having different range of flower colour and height and can be used for different floricultural purposes.