Browsing by Author "Perera, G.Y.A.D.D."
Now showing 1 - 4 of 4
Results Per Page
Sort Options
Item Effect of Growth Regulators on In-vitro Shooting of Calathea ornata for Commercial Cultivation(Uva Wellassa University of Sri Lanka, 2019) Maheepala, G.H.N.; de Silva, D.; Kaliyadasa, P.E.; Perera, G.Y.A.D.D.Clathea ornata is a foliage plant belongs to the family Marantaceae, having high commercial value all over the world as a house plant due its attractiveness. This study, focused to develop cost effective shoot induction protocol to obtain high number of shoots for commercial usage. The effects of different sterilization techniques, explant types, various combination and concentration of plant growth regulators on shoot induction were studied. The meristem explant showed high induction rate of shoots with minimum contamination percentage when explant treated with 20% (v/v) NaOCl for 10 minutes, 0.3% HgCl2 in 15 minutes and 70% alcohol 2 minutes. Further, the maximum number of multiple shoots were obtained in MS basal medium supplemented with 3.0 mg l-1 6Benzyl Amino Purine (BAP) and 3.5 mg l-1 Naphthalene Acetic Acid (NAA). Initiated shoot then sub cultured for shoot multiplication in terms of highest number of shoots and shoot length was observed in MS media in combination with BAP 3.0 mg l-1 with NAA 3.5 mg l-1.Item Effect of Sargassum wightii (Seaweed) Extract on In-vitro Sub-Culture Medium of Dendrobium Orchid(Uva Wellassa University of Sri Lanka, 2019) Madubhashi, R.M.M.B.; Herath, H.M.I.; Kaliyadasa, P.E.; Perera, G.Y.A.D.D.Dendrobium is one of the most beautiful orchid varieties having high demand as a cut flower as well as a potted plant. Large scale commercial production is possible only through vegetative propagation such as tissue culture. High cost of production is a major drawback of tissue culture which involves higher expenses for chemicals. This study focused on identification of bio-stimulatory effects of a seaweed (Sargassum wightii) extract on in-vitro sub culture medium of Dendrobium for quality plantlet production. Two experiments were carried out with 20 treatments in 10 replicates where, MS (Murashige and Skoog) basal medium with BAP (6-Benzyl Amino Purine) and without BAP were used for experiment one. For experiment two KnC (Knudson C) basal medium was used with coconut water, banana pulp and without coconut water, banana pulp. Treatments were prepared with combination of seaweed extract of 5%, 10%, 25% and 40% concentrations for above basal media. MS medium with BAP and KnC medium with coconut water, banana pulp without adding seaweed extract were used as control. Plantlets in MS medium with BAP and 10% seaweed extract showed significantly higher (p<0.05) plant height, number of shoots, number of leaves and dark green color leaves whereas higher number of roots were recorded in MS medium without BAP but with 10% seaweed extract compared to the control. Plantlets in KnC medium supplemented with coconut water, banana pulp and 10% seaweed extract showed significantly higher (p<0.05) plant height, number of shoots, number of leaves, number of roots and dark green color leaves compared to the control. Comparatively, MS medium with BAP and 10% seaweed extract showed good performance, which is suitable for commercial plant production.Item Evaluation of Seed Dormancy, its Associated Seed Morphological Characteristics, and Seed Vigor of Improved Rice Varieties in Sri Lanka(Uva Wellassa University of Sri Lanka, 2021) Jayasundara, J.M.S.P.; Ilangakoon, T.K.; Ranawana, S.R.W.M.C.J.K.; Perera, G.Y.A.D.D.Improved rice varieties may have different durations of seed dormancy and level of seed vigor, but no proper information is available to make use of them for farmers. This research was conducted at the Rice Research and Development Institute, Bathalagoda during 2020/2021 Maha season to identify the dormancy period, seed characteristics associated with dormancy and vigor of improved rice varieties in Sri Lanka. The experiment design was a completely randomized design with three replicates. Varieties were categorized by maturity period and seeds of 56 varieties were obtained from one week after harvesting. The dormancy period of each variety was considered from one week after harvest until it reached 85% germination as determined by weekly germination tests. Seed vigor was determined by % germination using cold test. Thousand–grain weight, maturity age, seed shape and pericarp color were recorded. Significant variations were observed for the dormancy period and seed vigor among varieties. Ld 355, At 401, Bw 363, Bg 94-1, At 362, Bw 452, Bg 250, Bg 400-1, Bg 454, At 308, Bg 292-6b, Bg 455, Bg 450, and Bg 310 overcame the dormancy at t third week. Bg 359, Bg 357, At 353, Bg 358, At 453, Bg 364, Bg 379-2, Bg 90-2, BG 11-11, Bw 372, Bg 305, At 309 and At 451 lost dormancy in fourth week. Bg 352 showed the longest dormancy breaking period (eight weeks) followed by Bg 252, Bg 403, and Ld 371 (seven weeks). Bw 400 had no dormancy period. Bg 407-H, Bw 351, Ld 356, Ld 365, Ld 408, Bw 301 and At 405 had a shorter dormancy period (two weeks). Bg 454 showed the highest vigor (93.3%), while At 402 (90.7%), At 309 (90.7%), Bg 11-11 (90.7%) and Bg 371 (86.7%) also had comparatively high vigor. Bg 379-2 showed the lowest seed vigor (8.0%) followed by At 401 (15.3%), At 405 (11.3%), Bw 351 (8.7%) and Ld 356 (10.7%). The relationships between dormancy period and thousand-grain weight, maturity days, pericarp color and grain shape were not significant (p≥0.05). The results of this study will help farmers to determine the sowing time after harvesting and to select suitable varieties under stress conditions. Keywords: Breaking dormancy; Germination; Improved rice varieties; Seed characters; VigorItem Screening a Bean Germplasm for Fusarium Wilt Disease, Caused by Fusarium oxysporum f. sp. phaseoli(Uva Wellassa University of Sri Lanka, 2016) Perera, G.Y.A.D.D.; Chandrasena, G.; Silva, P.D.P.M.D.; Somachandra, K.P.Fusarium wilt or Fusarium yellows is an economically important fungal disease of common bean worldwide. The causal agent of this disease is Fusarium oxysporum f. sp. phaseoli. The study was conducted to find the suitable medium for the multiplication and to determine the reaction of 30 common bean accessions, including two susceptible controls (Wade and Keppetipola Nil) to the Fusarium oxysporum isolates under greenhouse condition. Isolates of the pathogen were collected from the root and stem fragments of common bean plants grown in the production fields of Regional Agricultural Research and Development Center, Bandarawela. Species identity was based on the colony characters, nature of conidiogenous cell, and morphology of microconidia, macroconidia and chlamydospores. It was found that isolates had a relatively high growth in Bean extract Agar (BEA) medium, comparatively to Potato Dextrose Agar (PDA) and Corn Meal Agar (CMA) medium. Screening of the bean germplasm in the greenhouse was done by transplanting inoculated seven day old seedlings into pots filled with pasteurized (1:1) soil: sand medium. At 15 days after inoculation, the primary leaves showed epinasty symptoms and chlorotic areas appeared on leaves followed by necrosis at their margins of most accessions, including two recommended varieties. Disease severity was recorded 21 days after inoculation using a Disease Severity Index and it was observed that disease reactions in the germplasm varied from highly resistant to highly susceptible. Out of the 30 bean accessions including two recommended varieties there were 2 resistant, 19 intermediate and 11 susceptible accessions in the germplasm. Keywords: Common beans, Germplasm, Fusarium oxysporum f. sp. phaseoli, Fusarium wilt, Greenhouse screening