UWU Repository :: Browsing by Author "Kaliyadasa, P.E."

Browsing by Author "Kaliyadasa, P.E."

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Allelopathic Effect of Weeds Extracts on Growth and Yield of Tomato (Solanum lycopersicam L.)
(Uva Wellassa University of Sri Lanka, 2019) Ranaweera, R.A.T.L.; Kaliyadasa, P.E.; Ranawana, S.R.W.M.C.J.K.
The weeds are used as mulch, green manure and in compost production that could favourably or adversely affect on crops due to presence of allelochemicals. Such chemicals can be present in any part of the plant and release to microenvironment by leaching, root exudation, residue decomposition and other processes. This study was undertaken to evaluate the allelopathic effect of four common weed species available in agricultural lands on growth and yield of Tomato (Solanum lycopersicam L. var. Padma) under plant house conditions. The dried vegetative parts of Kura thampala (Amaranthus viridis), Bubovitiya (Clidemia hirta), Panithora (Cassia occidentalis) and Hulanthala (Ageratum conysoides) were used to extract aqueous solutions at different concentrations i.e. 4%, 8%, and 12%. Aqueous solutions were applied two weeks after transplanting and continued at one-day intervals until harvesting. Three replicates were used for each treatment in Complete Randomized Design with a control (water applied). Vegetative and reproductive characteristics of tomato such as plant height, No of leaves, No of branches, stem girth, total chlorophyll content, No of flowers, No of fruits, and fruit weight were recorded. Total polyphenol content of weed species and variation of soil pH and EC were analyzed in monthly intervals. The application of 4% of Hulanthala was shown the positive performances in vegetative growth, while 12% of Panithora reported the lowest values for both vegetative and reproductive growth of tomato compared to other treatments (p<0.05). Further, the highest total polyphenol content was in Bubovitiya and highest fruit weight was reported in the plants treated with 4% Bubovitiya compared to other weed species (p<0.05) with the highest brix value. It can be concluded that the weeds such as Hulanthala and Bubovitiya could be used in preparation of compost or in other organic applications at lower concentrations to obtain better growth and yield performances of tomato.
Antioxidant Properties and α-Amylase Inhibition Activities of Four Different Curcuma Species in Sri Lanka
(Uva Wellassa University of Sri Lanka, 2020) Samarasinghe, K.G.B.A.; Kaliyadasa, P.E.; Marasinghe, P.
The genus Curcuma belongs to the family Zingiberaceae comprises rhizomatous annual or perennial herbs. Curcuma has a long history of traditional uses ranging from folk medicine to its culinary uses. This study was undertaken to study the biological activities of rhizomes and leaves of four Curcuma species available in Sri Lanka namely, Curcuma albiflora, Curcuma aromatica, Curcuma longa, and Curcuma zedoaria. Fresh rhizomes and leaves of four Curcuma species were collected from their natural habitats in Wet and Dry Zones of Sri Lanka. Rhizomes and leaves were cleaned and cut into small pieces and oven-dried at 45 °C and 40 °C respectively for 12 hrs. Dried samples were ground into a fine powder. Methanol extracts from rhizomes and leaves were screened for total polyphenol content (TPC), antioxidant activity, and α-amylase inhibition activities. The TPC of dried rhizomes of Curcuma longa was the highest of all tested as 5.530 ± 0.012 g of GA equivalents per 1 g of the dried rhizome. The Methanol extracts of the rhizome and leaf samples of four species showed moderate antioxidant activity in the DPPH radical scavenging assay with IC50 values ranging from 150.253 ± 0.273 ppm to 389.051 ± 0.426 ppm. Interestingly the rhizome extracts of Curcuma aromatica, Curcuma longa, and Curcuma zedoaria exhibited higher α-amylase inhibitory activities (13.915 ± 0.023, 6.455 ± 0.117 and 9.492 ± 0.024 respectively) than the Acarbose drug which is an antidiabetic drug (28.273±0.615 ppm). The results revealed that the Sri Lankan Curcuma species have a potency to be used as a source of antioxidant and antidiabetic agents and it is important to increase the value of the unexplored medicinal herbs available in Sri Lanka. Keywords: Antioxidant, Anti-diabetic, Biological Activities, Curcuma
Awareness of and Adoption to the Recommended Management Practices of Big Onion Growers (Case Study in Dambulla D.S. Division)
(Uva Wellassa University of Sri Lanka, 2016) Nanayakkkara, D.N.; Kaliyadasa, P.E.; Amarakoon, A.M.C.; Padmini, S.M.P.C.; Chandrasiri, J.K.M.D.
Big onion is considered as an important cash crop in Sri Lanka. Within few decades big onion production has increased significantly along with the increasing demand for consumption. Though the production has increased, productivity is not satisfactory as average of 17 MT/ha where the potential productivity lies at 30-37 MT/ha. Therefore, it is imperative to study the knowledge level of the farmers and their adoption behavior regarding the recommended cultivation practices. Sixty five big onion growers who have not less than 5 years of big onion farming experience were interviewed in Dambulla D.S. division. Sample was selected randomly and data were collected using structured questionnaire. Total of 17 DOA recommended practices were considered initially but only 7 management practices were shown correlation with the level of awareness and adoption status. Therefore those practices viz use of recommended varieties, nursery sterilization procedure, seed treatment, spacing, seedling treatment, pre emergence herbicide application, correct harvesting stage and providence of optimum storage conditions were considered for further analysis. Results reveal that awareness on pre emergence herbicides and optimum harvesting stage has reported comparatively higher and they are 98.5% and 89% respectively. When considering the adoption, 76.9% of the respondents reported that they did not keep spacing while transplanting. Though the respondents have high awareness on optimum harvesting stage, only 27.7% well adopted to practice it. Factors affecting adoption are analyzed by using a multiple linear regression model and 5 factors were found significant. Respondent's age and off farm employment negatively affect the adoption level whilst education level, big onion farming experience and community leadership have no impact on adoption. According to the results it can be suggested that, though the farmers have sufficient knowledge on pre emergence herbicide application, correct harvesting stage and optimum storage conditions, majority has not at all adopted to those practices. Ultimately, it causes serious market based issues. Keywords: Adoption level, Awareness, Big onion, Management practices
Case Study on Waste Water Management Systems Adopted by Different Industries
(Uva Wellassa University of Sri Lanka, 2020) Nishshanka, J.S.; Kaliyadasa, P.E.; Ranawana, S.R.W.M.C.J.K.; Jeewanthi, P.W.
Different industries discharge wastewater with different contaminants in the production process. The heavy metals and other inert materials present in wastewater will contaminate the environment by causing normal drainage systems and natural water resources polluted. Therefore, it is a timely need to study detail on potential industries that generate wastewater and their adoption measures at present to treat the wastewater. With that objective twenty companies that represent eight different industries were identified using secondary data and a structured questionnaire was used to collect data in this study. Data were analysed by descriptive analysis method using Minitab 17 software. The findings of this study emphasized that different industries have adopted different wastewater management systems and analysis methods, however, their wastewater treatment methods at present are of very expensive. Further cost for water consumption by eight different industries is significantly different every month and recorded an average of Rs. 4,700,000.00 per month. Among the eight different industries and the highest cost recorded in the glove industry that costs about Rs. 5,000,000.00 per month. Moreover, 98% of industries prefer to implement a cost-effective wastewater treatment method in which each industry would be able to reuse the water and enhance the efficiency of water usage in a sustainable way. Keywords: Waste water treatments, Heavy metals, Industries, Water reuse
Comparative Study on the Phytochemical Composition of Medicinally Important Three Ocimum Species Available in Sri Lanka.
(Uva Wellassa University of Sri Lanka, 2020) De Silva, S.D.A.I.; Kaliyadasa, P.E.; Lochana, E.A.L.; Marasinghe, P.
Ocimum species have been used as an important medicinal herb, since ancient times but no recorded scientific evidence on morphological variations and phytochemical composition in Sri Lanka. Hence this study was conducted to determine the variation of morphological characteristics, total polyphenol content, antioxidant activity, and essential oil composition of three different Ocimum species namely; Ocimum sanctum, Ocimum gratissimum and Ocimum americanum. Healthy and fresh leaves of Ocimum plants were collected from Badulla and Welimada area. Morphological differences in leaves, flowers, roots, stem, and seeds of three Ocimum species were compared visually and recorded. Methanol extraction was performed using dried and powdered leaf samples and analysed total polyphenol content and antioxidant activity for three species using the Folin Ciocalteu reagent method and standard 2,2-diphenyl-1- picrylhydrazyl radical scavenging activity respectively. Hydro distillation was done to extract essential oils from Ocimum sanctum and Ocimum gratissimum and analysed by using Gas Chromatography – Mass Spectrometry method. There were differences and similarities between morphological characteristics among three species. The maximum polyphenol content was recorded in Ocimum americanum and the minimum was recorded in Ocimum sanctum. In determination of antioxidant activity, the highest half maximal inhibitory concentration was recorded in Ocimum americanum and the lowest was recorded in Ocimum gratissimum. There were differences in essential oil composition between Ocimum sanctum and Ocimum gratissimum. It can be concluded that there is a significant variation in morphological characteristics and phytochemical composition of three different Ocimum species available in Sri Lanka. Keywords: Antioxidant, Chromatography, Polyphenol, Scavenging, Spectrometry.
Comparison of Chemical Composition and Oil Yield of Vetiveria zizanioides from Different Agroecological Regions in Sri Lanka
(Uva Wellassa University of Sri Lanka, 2019) Gunawardana, D.M.; Kaliyadasa, P.E.
Vetiver (Vetiveria zizanoides) is a perennial grass used to extract vetiver oil from its roots. Vetiver oil has higher economic value in the international market and mainly used in perfumery, cosmetics industry and known to be a repellent with insecticidal properties. In Sri Lanka, vetiver grasses are mainly cultivated in tea lands to conserve soil and moisture. The quality and quantity of vetiver oil might be vary depending upon different growth conditions prevailed in the cultivated areas but no such reported evidences available. Hence, the objective of this study was to compare the chemical composition and yield of vetiver oil from main tea grown regions of Sri Lanka. Vetiver roots were collected from same age plants by using stratified sampling technique and samples from each stratum were selected randomly from nine agroecological zones including three major tea growing regions (low, mid and high grown). Fine powder from each root sample was prepared separately and 45g of powder used in extractions. Hexane was used to extract the vetiver oil by using Soxhlet apparatus and gas chromatography-mass spectrometry (GC-MS) was followed to analyze the chemical composition. Experiment was conducted in complete randomized design with three replicate and analyzed using analysis of variance. Average yields of the vetiver oils obtained in high, mid and low grown areas were 4.1%, 2.4%, 1.5%, respectively. There is a significant difference between oil yields of high grown and low grown vetiver (p<0.05) but no any significant difference between average yield in high and mid grown plants. In conclusion, highest percentage of oil was recorded in high grown vetiver with different chemical composition by showing the greater possibility of commercializing vetiver cultivation in high grown.
Determinants of the Level of Value Added Product Exportation in Tea Industry of Sri Lanka
(Uva Wellassa University of Sri Lanka, 2016) De Silva, D.A.O.C.; Kaliyadasa, P.E.; Amarakoon, A.M.C.; Balamurali, B.
Tea industry plays a vital role in Sri Lankan economy. Sri Lanka is still holding its' reputation in the global tea market though it is associated with number of problems like declining productivity, increasing cost of production, declining world share of production and continuous increase of price in Colombo auction etc. Those problems of the industry should be addressed in order to increase the country's revenue from tea exportation as bulk tea and Value Added Tea (VAT). In this context, VAT will become an important determinant of the future of Ceylon Tea industry as the global market trends changes towards value addition. Therefore objective of the study was to identify the determinants that affect the level of value added product exportation at different levels. The research was carried out in Colombo district with 32 tea exporters. A structured questionnaire was used to collect primary data. Secondary data for the study was gathered from statistical bulletins, annual reports, research papers, survey reports and other related documents. Tobit regression analysis was conducted to find the determinants. The result of the study revealed that there are six factors which significantly affect the level of value added product exportation in tea industry. Those were scale of exportation (small scale), bilateral agreement, brand ownership, number of new market approaches, and investment on research and development activities and attitude on value addition. Moreover, results reveal that small volume exporters tend more towards the value addition and with beneficial bilateral agreement, exporters are more involved in exporting value added tea products. Further, investment on research and development and having own brand has positive impacts on the exporter to push them towards value addition. Attitude on value addition and number of new market approaches have an effect on the level of value added tea exportation. It shows a positive relationship which encourages the value addition level of the company. Keywords: Export volume, Investment, Value Added Tea (VAT)
Determination of the Variation of Biochemical Profile of Commonly Grown Tea (Camellia sinensis (L.) O. Kuntze) Cultivar of TRI 2025 in Low Country Agro-ecological Zones
(Uva Wellassa University of Sri Lanka, 2019) Nirmala, M.H.G.S.; Kaliyadasa, P.E.; Alakolanga, A.G.A.W.; Jayasinghe, H.A.S.L.; Jeewanthi, P.W.
There is a unique taste, color and aroma of low country teas compared to other types of tea grown in Sri Lanka. Those properties are governed by the biochemical composition of the tea, basically the tea leaves. However, there was no reported study related to the variation of chemical profile of tea grown in different agro-climatic regions within the low country region. Therefore, this study was conducted to determine the variation of biochemical profile of commonly grown tea (Camellia sinensis (L.) O. Kuntze) cultivar of TRI 2025. Fresh tea leaves of TRI 2025 in 5th pruning cycle were randomly collected from eight selected plantations which represent four major tea cultivating agro-climatic regions WL1a, WL1b, WL2a, WL2b in low country. The estates were selected using stratified sampling technique and samples from each stratum were selected randomly from different tea estates in a way of including two estates in each agro-climatic region. The study was conducted during the period of onset of rain, from November to December, 2018. The fresh tea leaves placed on ice immediately after harvesting and transported. The leave samples were dried at 50 °C for 12 hours and crushed into fine particles. Chemicals were extracted from each sample using 1g of leaf powder in methanol for the analysis of polyphenols and reducing sugars while phosphate buffer was used for proteins extraction. Folin Ciocalteu regent method Lawry’s method and DNS reagent method was used to determine polyphenols, free sugars and total proteins with slight modifications, respectively. This study found that significantly different polyphenol and free sugar contents (p<0.05) were in teas grown in the four agro-ecological regions in low country of Sri Lanka but free total protein contents were not shown the significant difference.
Determination of the Variation of Biochemical Properties of Selected Tea Cultivar (Camellia sinensis (L.) O. Kuntze) in Mid Country
(Uva Wellassa University of Sri Lanka, 2019) Samarakoon, S.M.I.S.; Kaliyadasa, P.E.; Alakolanga, A.G.A.W.; Jayasinghe, H.A.S.L.; Jeewanthi, P.W.
In the tea trade, quality is used to indicate the presence of special desirable attributes in the tea liquor which are detected by physical appearance, smell and taste. The biochemical properties of tea is very complex and is currently a subject of broad medicinal and toxicological studies. This study was conducted to determine the variation of selected biochemical properties (polyphenols, free sugars, and total proteins) of commonly growing tea cultivar (Camellia sinensis (L.) O. Kuntze), of TRI 2025 among all tea growing agro ecological regions in Mid Country of Sri Lanka. Fresh tea samples (two leaves and bud) were collected from same aged plants by using stratified sampling technique and samples from each stratum were selected randomly from different tea estates of each agro ecological region in Mid Country (WM1a, WM1b, WM2a, WM2b, WM3a, WM3b, IM1a, IM2a, IM2b, IM3a). Collected samples were placed on an ice and transported and oven dried at 50 ˚C for 12 hours and crushed in to fine particles. Methanol extraction was performed for the analysis of total polyphenol content and reducing sugars while phosphate buffer was used to extract samples for the analysis of proteins. The concentrations of polyphenols, proteins, and free sugars were determined by folin Ciocalteu reagent method, Lowry’s method and dinitrosalicylic acid method respectively with slight modifications. The findings of this study shown that biochemical properties of teas such as polyphenol, total protein and free sugars contents were significantly different (p <0.05) among many tea growing ago ecological zones in mid country of Sri Lanka. Maximum polyphenol, free sugar, total protein contents were recorded in WM1b, WM2a and IM2a respectively. Minimum polyphenol, free sugar, total protein contents were recorded in IM2a, IM3a and IM2a, respectively. This sets a precedent for the characterization of biochemical profiles of mid grown tea of Sri Lanka.
Determination of the Variation of Biochemical Properties of Selected Tea Cultivar (Camellia sinensis (L.) O. Kuntze) in Up Country
(Uva Wellassa University of Sri Lanka, 2019) Thiruneelan, T.; Kaliyadasa, P.E.; Alakolanga, A.G.A.W.; Jayasinghe, H.A.S.L.; Samarasinghe, B.A.
Tea has an attractive aroma, good taste, and flavor, however; these properties could vary with climatic factors including temperature, sunshine hours and rain fall prevail in different agro-ecological zones in the growing areas. Therefore, this study was conducted to evaluate the chemical composition of Tea (camellia sinensis (L) O. Kuntze) var. TRI 2025 grown in different agro-ecological zones in Up-country. Fresh tea samples of TRI 2025 (two leaves & bud) were collected from the same aged plants by using stratified sampling technique from 11 regions, viz: WU1, WU2a, WU2b, WU3, IU1, IU2, IU3a, IU3b, IU3c, IU3d, and IU3e in the up country during the onset of rains. The fresh tea leaves were placed on ice immediately after harvesting and transported. The leaves were dried in an oven at 50 oC for 12 hours and dried samples were crushed in to fine particles. Methanol extraction was performed for the analysis of total polyphenol content and reducing sugars while phosphate buffer was used to extract samples for the analysis of proteins. The concentrations of polyphenols, proteins, and free sugars were determined by Folin Ciocalteu reagent method, Lowry’s method and Dinitrosalicylic acid method respectively with slight modifications. The findings confirm that chemical properties of tea in up country showed significant (p<0.05) difference among many tea growing ago ecological zones in Up-country of Sri Lanka. Maximum polyphenol, free sugar, total protein contents were recorded in IU3e, WU3 and WU1 respectively. Minimum polyphenol, free sugar, total protein contents were recorded in WU2a, IU3a and IU3c, respectively. This study sets a precedent for the characterization of biochemical profile of all tea growing areas in Up-country of Sri Lanka.
Development of an Instant Herbal Tea from Walkoththamalli(Scoparia dulcis) for Reduction of Blood Glucose Level
(Uva Wellassa University of Sri Lanka, 2010) Sarathchandra, P.W.S.H.; Kaliyadasa, P.E.
The study was carried out to identify the suitable plant part, drying period for the preparation of instant herbal tea of Walkoththamalli and to analyze consumer preference, quality of the product, chemical composition and pharmacological effect of the herbal extract to control the blood sugar level. Whole plant and leaves of the plant were selected as reliable plant parts and dried under 70 °C for 12, 24 and 24 hours to prepare the bags by filling 1.5 g of dried samples and microbial test was performed for four months to check the shelf life of the product by comparing the available standards for black tea. Organoleptic properties of finished product and herbal extract were evaluated using a sensory evaluation with thirty one panelists and Thin Layer Chromatography (TLC) with 5% methanol in chloroform solvent system was used to study chemical compounds available in the 95% ethanol herbal extract. Random blood sugar test and glucose tolerance test with 75 g of oral administration of glucose were used as clinical trails to test the effect of the herbal extract on blood sugar level (leaves dried for 24 hour at 70 °C) using five and three volunteers respectively. Among the six treatments, leaves dried for 24 hours was recorded the significantly highest (P<0.05) consumer preference for all parameters analyzed in the sensory evaluation. The same sample recorded the lowest microbial activity compared to the other samples. With the TLC all six samples showed that different banding patterns in the plates, which represent the availability of chemically active compounds in the herbal extracts and leaves dried for 24 hours at 70 DC was shown the highest number of bands under 254 nm UV light. The results of random blood sugar test and blood sugar level in glucose tolerance test showed that significant reduction in blood sugar levels of each volunteer with herbal extract than the control. According to the above results leaves dried for 24 hours at 70 DC was the best type to prepare the instant herbal tea from Walkoththamalli which is having the ability to reduce the blood sugar level. Key words: Blood glucose level, Thin Layer Chromatography, Chemical compounds, Microbial activity
Development of Micro-Propagation Protocol for Aponogeton dassanayakei
(Uva Wellassa University of Sri Lanka, 2018) Hettiarachchi, H.D.B.K.; Coswatte, A.C.W.W.M.C.L.K.; Senaratne, M.M.D.J.; Krishnarajah, S.A.; Kaliyadasa, P.E.
Aponogeton is a genus of freshwater aquatic plants and there are five Aponogeton species native to Sri Lanka with three endemic members. They have a high demand as an ornamental aquarium plant, food source and medicinal herb. Due to these reasons over exploitation of plants from natural habitats is common with poor attention on conservation. Aponogeton dassanayakei is a newly identified Aponogeton species from Sri Lanka. This study was carried out to develop a micropropagation protocol for newly identified Aponogeton dassanayakei. Treatments included full strength Murashige and Skoog (MS) solid basal media supplemented with combinations of 6-benzylaminopurine (BAP) (0.00, 1.00, 2.00 mg L-1) with 0.10 mg L-1 Indole-3-acetic acid (IAA) and without IAA for both shoot initiation and multiplication in seed culture. Ten replicates obtained per each treatment. During shoot initiation seed germination rate, seedling height and number of leaves per seedling were taken as the response variables and shoot multiplication stage plant height and number of leaves were considered. Application of hormones showed significant effect (p < 0.05) on both number of leaves and seedling height but not on seed germination rate in shoot initiation. Hormones supplemented in solid media during shoot multiplication were shown significance difference (p < 0.05) in plant height but not in number of leaves. According to the study, MS medium supplemented 1.00 mg L-1 BAP is the best for shoot initiation. MS medium containing 2.00 mg L-1 BAP is best for shoot multiplication. The study demonstrated that micro-propagation could be useful for large scale propagation of Aponogeton dassanayakei while conserving the plant in natural habitat.
Development of Non-Destructive Image Analysis Protocol to Assess the Quality of In-Vitro Propagated Orchid Plantlets
(Uva Wellassa University of Sri Lanka, 2019-02) Weerakkody, E. H.; Kaliyadasa, P.E.; Jayasekara, N. E. C.
In-vitro propagated plants are vulnerable to external changes leading poor growth performances depends on the vigour at hardening stage. The accurate procedure to evaluate in-vitro propagated plants, prior to hardening is vital through incorporating modern technologies such as image processing, to mitigate the drawbacks in visual evaluation which is used at present. Therefore, this study focuses on developing an image analysis protocol to assess the quality of in-vitro propagated Orchid plants. Digital photographs of the culture vessels of Orchid plants which were at the stage of acclimatization were taken inside an illuminated chamber. A visual scoring scale was developed in a scale of 0 to 5 to rank individual plantlets in each vessel. Plant images were isolated from the background and mean red (R), green (G) and blue (B) values were calculated from the segmented images. Through the RGB values, Yellowness, Hue (H), Saturation (S) and Intensity (I) values and thereby Dark Green Colour Index (DGCI) were calculated. Further vegetation indices such as Photosynthetic Vigour Ratio (PVR), Plant Pigment Ratio (PPR), Redness Index (RI), and Green Leaf Index (GLI) were also calculated. The visual evaluation score, DGCI, Yellowness and vegetation indices values were tested to determine the correlation between visual evaluation score and other values obtained using digital photographs. Among all indices, strong correlation (p<0.05) was observed in PVR and RI and then the composite of the values were accordingly regressed with visual evaluation score to select healthy and chlorotic tissues. The high possibility of the use of PVR and RI values composite (PR) to determine the quality of in-viro propagated plantlets, was determined by high R squared value. The function for the quality of the Orchid plants was developed using constant coefficient and coefficient of PR, obtained through regression that could easily apply to select the high quality plantlets.
Effect of Clone type on Storage Hardening and Gel Content of Raw Natural Rubber
(Uva Wellassa University of Sri Lanka, 2016) Delman, H.W.O.C.; Kaliyadasa, P.E.; Arachchi, M.P.; Attanayake, A.
Latex is the only non-synthetic elastomer in wide use derived from the milk-like liquid of the Rubber tree. At present the country ranks among the world's top ten largest producers and 7111 largest exporter of natural rubber. Even though Sri Lanka is the one of the leading manufacturer of raw rubber, most of the product is carried out in other countries and those rubbers should be kept under storage conditions until use. During transportation or upon storage natural rubber exhibits different storage properties. Hence, rubber industry has increase the requirement for quality and uniformity of natural rubber. The objective of this study was to assess effects of clone type on gel content and storage hardening of natural rubber. Ten different clones rubber were used as samples in this study which are RRISL 201, 202, 203, 205, 206, 211, 216 217, 219 and RRISL 222. Properties of raw rubber were analyzed using standard methods of Gel content, Mooney viscosity, stress relaxation rate, Green strength, Initial plasticity and Hardening plasticity. Minitab 16 statistical software was used to analyze the qualities of nine replicates from ten different clones. Most clones were showed medium and hard viscosities and none of clones reported low viscosities. Correlation between Mooney viscosity and Initial Wallace plasticity were analyzed using regression and identified that there is a relationship among them. The RRISL 203 clone gave relatively high Mooney viscosity, Po, stress relaxation rate and green strength. Therefore it can be concluded that RRISL 203 clone consisted high molecular weight. As all the tested properties of RRISL 217 clone have met the specification requirements for rubber processing, can be successfully used in product manufacturing. Key Words: Gel content, Storage hardening, Mooney viscosity, Green strength, Initial plasticity, clones
Effect of Drought on Shoot, Root and Yield Parameters of Selected Rice Lines
(Uva Wellassa University of Sri Lanka, 2020) Manurangi, D.D.M.; Illangakoon, T.K.; Kaliyadasa, P.E.; Jeewanthi, P.W.
Rice (Oryza sativa L.) is the major food crop in Sri Lanka. That occupy 34 percent (0.77 /million ha) of the total cultivated area in Sri Lanka. Drought is one of the major environmental constraints severely reducing rice yields, making serious threat to global rice production. This study was conducted using eight rice lines including newly improved and exotic rice lines. Drought tolerant rice variety, Bg251 used as the control. The experiment was conducted inside a plant cage using Complete Randomized Design with three replicates for each rice variety and with 96 experimental pots. Seven days old seedlings were established in pots and drought condition were initiated after two weeks of planting. Growth parameters like plant height, chlorophyll content, shoot dry weight and flag leaf length were measured and Drought Tolerant Degree index was estimated. Root parameters were measured using WhinRHIZOpro root scanning machine. Further yield parameters like panicle weight, spikelet no per panicle, Yield and 1000 grain weight were measured. ANOVA process was conducted at 5% significant level for data analysis. Mean comparison was done by using Turkey’s comparison. And Pearson ’correlation was performed to investigate the relationship between the parameters. AERON 9-3, IRDTN 7- 11 and IRBBN dhana were identified as highly drought tolerant compared with BG 251. AERON 9-3 identified as a cultivar with good yield as well as good Drought Tolerant Degree value. And Drought Tolerant degree index was identified as simple and accurate drought screening method. Keywords: Drought Tolerant Degree, Drought Tolerance, Panicle weight, Spikelet no per panicle
Effect of Explant Source and Hormone Combinations on In –vitro Propagation of Different Genotypes of Gerbera (Gerbera jamesonii)
(Uva Wellassa University of Sri Lanka, 2010) Weerasinghe, S.K.M.M.; Hearth, H.M.I.; Kaliyadasa, P.E.; Withanage, N.S.
This research was carried out to study the effect of explant and hormone combinations on in-vitro propagation of different genotypes of Gerbera, in order to produce high quality, disease free planting materials for commercial cultivation. Experiments were conducted to select the best hormonal combinations among TDZ, IAA, 2,4-D and to select best calli and to find out the best hormonal combination to develop green calli. Treatments were replicated five times and allocated according to the complete randomized block design. In experiment one, leaf and capitulum of explants Ecco and Winter Queen varieties were cultured in MS media supplemented with different combinations of TDZ, IAA and 2,4-D. In experiment two, leaf and capitulum explants of the hybrid of Ecco and Winter Queen were treated with the selected best hormone combinations from experiment one. The selected, best dal from experiment one and two were transferred in to the multiplication media (MS with 0.5 mg/I BA, 0.5 mg/I Kinetin and 0.4 mg/I IAA) in experiment three, to find out the best hormone combinations to develop the desired green calli. Culture conditions for all experiments were maintained, at 26 ± 2 °C, 25% RH and 16 hour photoperiod. All experiments were designed using CRD with 5 replicates. In experiment one and two, the percentage of calli growth was recorded. In vitro propagation of variety Ecco and Winter Queen with capitulum explant can be combined with 0.5 mg/I IAA and 0.5 mg/I TDZ economically, as there was no significant difference (P<0.05) in percentage of calli growth and green calli development compared to 0.5 mg/I IAA and 1.0 mg/I TDZ. In hybrid, capitulum explant was not significantly succeeded (p<0.05) whereas leaf explant recorded the highest calli growth (85%) at p<0.05 with 1.0 mg/I 2,4-D. The best green calli growth in multiplication media was recorded in sixth weeks after establishment and no significant growth was observed thereafter. The results of above experiments revealed, that the hormone combinations of 0.5 mg/I TDZ and 0.5 mg/I IAA with capitulum explant in variety Ecco and Winter Queen and the leaf explant of hybrid with 1.0 mg/I 2,4-D can be successfully used in in-vitro propagation of Gerbera in commercial scale. Key words: IAA, TDZ, Capitulum, Multiplication, Calli growth
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.
Effect of Initial Seed Moisture Content on Seed Growth Quality Parameters and Storability of Brinjal (Solanum melongina L.)
(Uva Wellassa University of Sri Lanka, 2016) Kayalvizhy, S.; Kaliyadasa, P.E.; Premathilake, U.G.A.T.; Priyantha, M.G.D.L.
Quality seed is the basis in high agricultural productivity and average seed germination in brinjal was reported as below 70% under local conditions. This problem was reported especially in "Lenairi" and "Padagoda" brinjal varieties. Hence this experiment was carried out to compare the effect of Initial Seed Moisture Content (ISMC) on growth quality parameters under non storage and storage conditions in different brinjal varieties. Experiment was designed in Complete Randomized Design with two and three factors having four replicates in each under non storage and storage conditions respectively. Three ISMC, 9%, 8%, 7% and four different varieties, Lenairi, Padagoda, Thinnavelli purple, Amanda were taken for this study. Brinjal sebds were tested initially for growth quality parameters and samples were stored for two months under ambient and refrigerated conditions. Findings revealed that, there was a highly significant effect of ISMC, variety and storage condition on seed germination and vigor. Under non storage condition, highest germination percentage (79.5%) was recorded in Padagoda at 9% initial seed moisture content. Highest vigor index (2147) was recorded in Thinnavelli purple at 9% initial seed moisture content. Under storage condition highest germination percentage (86.5%) was recorded in Padagoda at 8% initial seed moisture content stored in refrigerator. Highest vigor index (2837) was recorded in Amanda at 9% initial seed moisture content stored in refrigerator. Results indicated that highest germination percentage was observed at 9% ISMC under non storage condition. Seeds stored in refrigerator at both 9% and 8% ISMC were superior in storability compared to those stored in ambient condition in growth quality parameters. However, further studies are necessary to identify more suitable ISMC for commercial scale brinjal cultivation. Keywords: Brinjal, Initial seed moisture content, Germination, Vigor
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.
Effect of Selected Plant Aqueous Extracts on Controlling of Brown Plant Hopper (Nilaparvatalugens), Paddy Bug (Leptocorisaoratorius) And Rice Leaf Folder (Cnaphalocrocismedinalis)
(Uva Wellassa University of Sri Lanka, 2018) Ekanayake, E.M.A.U.; Sarathchandhra, S.R.; Weerawasnsa, A.N.R.; Kaliyadasa, P.E.
Cnaphalocrocismedinalis, Nilaparvatalugens and Leptocorisaoratorius are majorinsect pests in rice which cause a considerable loss of annual rice yield. Synthetic pesticides are widely used to manage pest attacks in rice cultivations in Sri Lanka. Compared to the synthetic pesticides, plant based extracts are usually safer to the environment and humans. This study was conducted to test the bio-efficacy of four selected plant extracts vizAzadirachtaindica (Neem), Annonamuricata (Anona), Calotropis gigantean (Wara) and Lantana camara (Gadapana) against Cnaphalocrocismedinalis, Nilaparvatalugens and Leptocorisaoratorius and to compare the insecticidal activity of the commonly used synthetic pesticide with plant extracts against the above-mentioned pests. Aqueous extractions of these plant species were made in three concentrations. i.e.10 g/100 ml, 50 g/100 ml and 100 g/100 ml.Tested synthetic pesticides against Cnaphalocrocismedinalis, Nilaparvatalugens and Leptocorisaoratorius were Tebufenozide (20 m1/101), Thiamethoxam (5 g/16 1) and Carbosulfan (560 mllac) respectively. The experiment was laid out in Complete Randomized Design with fourteen treatmentsincluding a controlwith three replicates for each pest. Ten second instar larvae of Cnaphalocrocismedinalis, fifteen adult of Nilaparvatalugens and thirty adult of Leptocorisaoratorius were taken as experimental units. Bioassay methodology was used. Mortality percentage at 96 hours after application of each extract was recorded. It was concluded that in controlling of Cnaphalocrocismedinalis, Nilaparvatalugens and Leptocorisaoratorius, the most efficient plant extracts were Annonamuricata (50 g/100 ml), Azadirachtaindica (50 g/100 ml) and Calotropis gigantean (10 g/100 ml) respectively.

Browsing by Author "Kaliyadasa, P.E."

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