Faculty of Humanities and Sciences
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Publication Open Access Effect of hot ethral-dip treatment for improving peel colour development and reducing stem-endrot of ‘Karuthacolomban’mango(Sri Lanka Department of Agriculture, 2004) Sarananda, K. H; Wijesinghe, W. A. J. P; Dulani, H. N; Peiris, C. NPoor colour development of the peel and high incidence of stem-end-rot development are the major reasons for excessive postharvest losses in mango, variety” Karuthacolomban ‘. Experiments were conducted to investigate the effect of artificial ripening by application of ethral at ambient (26ºC), 48º and 52ºC on reducing postharvest losses. Time taken for ripening was shortened when the treated temperature was increased. Peel colour development was improved when fruits were treated at 52 C. Total soluble solids and titratable acidity of induced fruits remained similar to those of control at table ripe stage. No difference observed in the sensory evaluation of ripe mango indicated that the taste, smell and flavour were not affected by the application of ethral. Fruits inoculated with Lasiodiplodia theobromae showed less severity of stem-endrot when those fruits were induced for ripening at 52 C with ethral. When inoculated fruits were allowed to ripen naturally a high disease severity was observed. Therefore, after harvesting, mature” Karuthacolomban ‘mangoes could be treated with hot ethral (1 ml/l H2O) at 52 C for 3 minutes to induce ripening resulting in an attractive peel colour and a low severity of stem-end-rot.Publication Open Access Breeding and selection of tomato F1 hybrids for yield and fruit quality characters(Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 2005) Alwis, L. M. H. R; Perera, A. L. T; Fonseka, H; Peiris, C. NTomato (Lvcopersicon esculentum Miller) of the family Solanaceae is one of the most important vegetable crops grown in Sri Lanka. To understand the actual consumer requirements, especially in terms of fruit quality characters, an extensive survey was carried out. Results revealed that for home consumption, a majority preferred acidic, round to flatshaped, medium-sized fruits, red in colour for curries, salads and sandwiches. The Government of Sri Lanka has also identified the production of local vegetable hybrids as a matter of high priority. With this information, a half diallel genetic crossing design was carried out to produce 36 F, hybrids using nine local and foreign varieties at the Agricultural Biotechnology Centre, University of Peradeniya. These were evaluated in the Meewatura farm of the Faculty of Agriculture, University of Peradeniya. Yield and fruit quality characters including brix, acidity and fruit shape and colour were evaluated. General combining ability (GCA) and specific combining ability (SCA) were significant indicating the importance of both additive and dominance gene action. Out of the 36 Fi tomato genotypes; T068 was selected as the best hybrid for the tourist industry as it showed heterobeltiosis for yield (48%) and low acidity, while T025 was selected as the best hybrid for local consumption as it too showed heterobeltiosis for yield (76%) with high acidity. Both hybrids showed that yield potentials were much higher than the currently used varieties.Publication Open Access Development of new high yielding chilli hybrids (Capsicum annuum L.) based on heterobeltiosis and characterization of parental germplasm for DNA polymorphisms(Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 2006) Millawithanachchi, M. C; Perera, A. L. T; Peiris, C. N; Fonseka, H. MTwenty-eight hybrids of chilli (Capsicum annuum L.) were produced through the half Diallel genetic design using improved chilli varieties, MI 1, MI 2, KA 2, Arunalu, MI Hot, IR, Thiwari and Hot Pepper. Hybrids and parents were evaluated for yield characteristics using a 7 x 7 lattice design under the field conditions of Meewathura farm, University of Peradeniya, from June to November 2004. Performance for total yield, total number of pods, average pod weight, plant height, plant width, pod length, and dry matter percentages were significantly different among tested genotypes. High heterobeltiosis was observed for total yield, while heterosis for total number of pods, average pod weight, and dry matter percentage was low. H 42 was the best performing hybrid with 113.24% heterobeltiosis for total yield having early flowering characteristics. PCR, based on RAPD primers OPM 05 and OPM 11 gave polymorphic …Publication Open Access Need for quality assurance and accreditation in Sri Lankan Universities(Quality Assurance & Accreditation Council of the University Grants Commission, Sri Lanka, 2007-01) Peiris, C. NThis paper presents a brief description of the Quality Assurance framework introduced into the Sri Lankan higher education system recently. At present, the Sri Lankan Quality Assurance framework composed of four main components, namely Codes of Practice, Subject Benchmarking, Credit and Qualification Framework and External Quality Assessments. The paper discusses some of the lessons learnt and experience gained at the initial phase of the External Quality Assessment Process. Finally, it provides some suggestions for the future development of the Quality Assurance programme in Sri Lanka.Publication Open Access Gamma-hydroxybutyrate accumulates in green tea and soybean sprouts in response to oxygen deficiency(Canadian Science Publisher, 2003-10) Shelp, B. J; Allan, W. L; Peiris, C; Bown, A. WGamma-hydroxybutyrate (GHB) is an illicit drug, which may be derived in plants from a stress-inducible metabolite known as gamma-aminobutyrate. Here, oxygen deficiency caused the accumulation of GHB in green tea and soybean sprouts (76 and 155 nmol g-1 fresh weight, respectively). These findings demonstrate that GHB levels are elevated in severely modified atmospheres, but they pose no risk to human health. Further work is required to assess the extent of this phenomenon.Publication Open Access Preservation of Plumeria rubra L.(Rathu Araliya) for dry flower arrangements(Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 2007) Karunananda, D. P; Peiris, SThis study was carried out to optimize a flower drying technique applicable for long term preservation of Plumeria rubra L. in dry flower arrangements. Silica gel, borax with corn meal, river sand, sea sand and air drying were used to dry the P. rubra flowers. Retention of colour and shape of dried flowers were evaluated comparing against Royal Horticultural Colour Chart and designating weighted scores for each colour. Reduction of flower weight was used to select the methods for rapid drying. Preservation using silica gel and river sand showed significantly performances in colour retention at the completion of drying at four days. Silica gel, river sand, borax with corn meal and sea sand showed significantly different performances (p= 0.05) in shape retention when compared with the control. P. rubra petiole fixed well to metal wires showing ability of use for dry flower arrangements.Publication Embargo Control of circadian rhythm-regulated nyctinastic movement in water lily (Nymphea stellataWilld.) flowers(Taylor & Francis Group, 2005-01-01) Samarakoon, U. C; Peiris, SFlowers of Nymphea stellata Willd., like other water lilies, are subject to circadian clock-controlled petal closure in the afternoon. To investigate the effects of plant growth regulators, and various other chemicals, in arresting nyctinastic movement (petal closure), cut flowers of N. stellata were exposed to different concentrations of gibberellic acid (GA), benzyl amino purine (BAP), naphthalene acetic acid (NAA), abscisic acid (ABA), ethanol, AgNO3, NaCl or Rinso (laundry detergent powder). The most effective treatment to control the biological clock of petal movement was keeping flowers continuously in 25 mg l–1 GA. This treatment kept flowers open, to an acceptable cut flower standard, for over 28 h. Continuous exposure to 5 mg l–1 BAP also kept flowers open to the same acceptable standard for over 15 h. Considering low-cost applications, immersing flowers in 25 g l–1 NaCl for 1 h kept them open for almost 17 h, to an acceptable cut flower standard. Immersing in 2 g l–1 Rinso (Unilever, Sri Lanka) for 1 h also kept flowers open for 14 h in an acceptable condition. By inhibiting nyctinastic closure using any of the above chemicals, N. stellata could now be considered and exploited as a cut flower.Publication Open Access Effects of selected post harvest treatments on vase life of cut flower gladiolus (Gladiolus grandiflorus)(Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 2000) Premawardena, P. S; Peiris, B. C. N; Peiris, SA postharvest storage study with different treatments was carried out to investigate a procedure in prolonging the vase life of cut-flower gladiolus. Various chemical and non chemical treatments which are locally available were used. In comparison with the control (distilled water), beverages such as 7-UP™ in different concentrations, specific anti-ethylene compounds, silver nitrate and silver thiosulphate (STS), benzyl amino purine (BAP) in different concentrations, hot water treatment to the base ofthe flower stalk as a sterilizing method, maintaining the pH at 3.5 using HCI, eylene oxidization with KMn04 and ethylene absorption with activated charcoal were tested The longest vase-life and the best visual quality were achieved by gladiolus flowers treated with 25% 7-UP™. Next best visual quality were achieved by Silver nitrate, 2.25% 7-UP™, 4 mg t' KMn04 and STS in the descending order. Flowers treated with 2 mg t' KMn04 and the control (distilled water) had the lowest vase life. The visual quality was lowest in flowers treated with 2 mg t1 KMnO^ When the cots ofcompounds used were considered the study indicates that the treatment 7-UP™ and KMn04 were found to be the cheapest, while silver nitrate and silver thiosulphate are comparatively expensive.Publication Open Access Transient expression of uida reporter gene in regenerable callus tissues of Anthurium andraeanum lind. by agrobacterium mediated transformation(Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 2000) Yakandawala, G; Peiris, S; Yakandawala, Y. L. NA tissue culture scheme for plant regeneration via callus, and a protocol for gene transfer to regenerable callus are described for Anthurium andraeanum variety A vo Nette. Callus was induced from shoot bases and from leaf blades of Anthurium andraeanum on modified MS media containing 0.3 mg t' 2,4-D and 0.5 mg t' BAP. Shoot bases, leaf blades with a single cut at the base, and sectioned leaf blades produced callus at frequencies of 90%, 20% and 8%, respectively. Plant regeneration was obtained at a high frequency in all callus types, irrespective of their origin, in modified MS media containing 0.5 mg t' BAP. Callus was tested for gene transfer efficiency by 2 Agrobacterium tumefaciens strains, C58 andLB4404, carrying binary vector p CAMBIAi } oi containing hpt and uidA reporter genes under plant expression signals. Transient expression of uidA gene monitored by GUS histochemical assay was observed only in callus inoculated with Agrobacterium strain LB4404 at a frequency of 3.33%.Publication Open Access Preliminary investigation of preservation methods to produce dried flowers of rose and statice(Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 2000) Kumari, D. L. C; Peiris, SAn experiment was carried out to investigate methods which preserve rose and statice to retain its high quality standards as dried flowers. Air-drying, glycol preservation and use of desiccants were applied as preserving methods. Colour of petals, dryness of petals and overall appearance of the flower at the end of the drying process were evaluated as quality standards. The highest quality standard in rose was shown within 2 weeks by the preservation method using silica gel as a desiccant. Air drying showed better results than glycol when preserving rose. In statice, air drying was the best method which retained quality standards. The highest score was obtained in the 4'h week Statice exposed to glycol preservation did not show high quality standards. This experiment revealed the best preservation methods for rose and statice are silica gel desiccant and air drying respectively