Research Publications Authored by SLIIT Staff

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This collection includes all SLIIT staff publications presented at external conferences and published in external journals. The materials are organized by faculty to facilitate easy retrieval.

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THE PERSPECTIVES OF UNIVERSITY ACADEMICS ON THEIR INTENTION TO PURCHASE GREEN SMARTPHONES IN SRI LANKA
(Informing Science Institute, 15 June 2023) Janak, P; Kumarasinghe; Huang, Q; Rathnayake, N
Aim/Purpose Most people use their phones for work and communication. Businesses today require sustainable mobile phones to limit the environmental impact of mobile phones. According to the Environmental Protection Agency (EPA), a green product uses less energy. Green smartphones need low radiation emission, are made from recyclable materials, and are designed to last longer than typical smartphones. Further, the manufacturing process needs to have a low environmental impact. The present study aims to identify the influence of variables (such as Green Awareness, Environmental Concern, Altruism, and Willingness to Pay) on green smartphone purchase intention among academics in the Sri Lankan higher education sector. Background With the swift technological advances, almost everyone has begun to use smartphones. Simultaneously, smartphone manufacturers have begun to release cutting-edge smartphone models to the general public. As a result, it has generated a significant amount of e-waste for the environment. As a result, therefore, the sustainability of green smartphones has become a major societal concern in the developed world, but this is not yet true in the developing world Methodology The study used a qualitative research method in which the authors attempted to acquire primary data by conducting in-depth interviews with academics from the Sri Lankan higher education sector using a semi-structured interview guide. Eight interviews were conducted, audio recorded, and word-to-word transcribed for content analysis. Researchers used content analysis to determine the presence, meanings, and linkages of specific words, themes, or concepts. Contribution The findings provide important environmental insights for smartphone makers and society, such as introducing waste reduction programs and energy-saving practices and creating awareness among people to change their consumption patterns. The study will provide valuable insights into the green smartphone phone purchasing intentions of academics in a developing country, especially helping green smartphone producers and marketers construct effective tactics with the insight of the current study based on university faculty members’ viewpoints. Findings The current study’s findings revealed that academics acknowledge the need for environmental protection with an awareness of the green concept and environmental concerns. According to the interviews, most participants intended to move from their present smartphone to an ecologically friendly phone, as they explained on altruism. This implies that even academics in underdeveloped countries are worried about environmental issues and have shown a more robust understanding of these issues and how environmentally aware individuals’ activities may assist the earth’s sustainability. Further, academics have a willingness to pay for a green smartphone. Recommendations for Practitioners Academics prioritize environmental conservation when making purchases. This implies that manufacturers and enterprises should focus on developing and innovating more environmentally friendly products. Recommendations for Researchers Using only academics as a sample approach is severely limited if the study’s population comprises people with various qualities. Nevertheless, this study presented only four independent variables, and more factors impacting green smartphone purchasing intention may exist. As a result, it is proposed that future research consider other factors. Impact on Society It was discovered that most participants displayed altruism in their product purchases, implying that policymakers must strengthen the moral practice of concern for the welfare and happiness of other humans, even in developing countries. Future Research A further in-depth study focusing on many perspectives, such as limits and motivations for purchasing green products in various socioeconomic groups with varying moderating factors such as gender, education, and rural-urban, would be advantageous. Individual (emotions, habits, perceived behavioral control, trust, values, personal norm, knowledge) and situational (availability, product attributes, subjective norm, brand, eco-labeling) variables should be included in future research
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On the longitudinal harmonic motion of an elastic bar embedded in an elastic half-space
(Pergamon, 1987-01-01) Shah, A.H; Rajapakse, R. K. N. D
The present study is concerned with the motion of a long cylindrical elastic bar which is partially embedded in a homogeneous elastic half-space and subjected to a harmonic axial load. Initially Green's functions corresponding to axisymmetric harmonic ring loads are derived and presented explicitly. It is found that the direct extension of elastostatic solution schemes to solve elastodynamic problems may lead to erroneous solutions due to the inability of these algorithms to properly account for inertia effects. Some discrepancies in existing solutions with respect to the inertia component of the bar are shown. An efficient solution scheme, based on Lagrange's equation of motion and a discretization technique, is presented to solve the title problem. Numerical results are presented to illustrate the influence of bar flexibility, mass density, geometry, and frequency of excitation on the axial impedance of the system.
Open Access
Visibility of pharyngeal structures as a predictor of difficult intubation
(Blackwell Publishing Ltd, 1987-10) Charters, P; Perera, S. V. T; Horton, W. A
Visibility of pharyngeal structures as a predictor of difficult intubation Page 1 Correspondence 1115 Visibility of pharyngeal structures as a predictor of difficult intubation We would like to comment on the study by Samsoon and Young (Anuesihesh 1987; 42: 487-90) since we also have experience with the test which forms the basis of their report. Mallampati’s test scores the visibility of pharyngcal structures (faucial pillars, soft palate and uvula) in an attempt to predict difficult tracheal intubation. Three of us used this test as part of a pre-operative asscssmcnt in a study about tracheal intubation. Sainsoon and Young did not make it clear in their paper hut thcy did not make the assessment in the way described by Mallampati. We also chosc to examine our patients with ‘the head in the neutral position’ and the observer sitting ‘opposite at eye level’. We graded paticiits class 1 to 3 as originally described because Mallampati …
Open Access
Visibility of pharyngeal structures as a predictor of difficult intubation
(Blackwell Publishing Ltd, 1987-10) Charters, P; Perera, S. V. T; Horton, W. A
Visibility of pharyngeal structures as a predictor of difficult intubation Page 1 Correspondence 1115 Visibility of pharyngeal structures as a predictor of difficult intubation We would like to comment on the study by Samsoon and Young (Anuesihesh 1987; 42: 487-90) since we also have experience with the test which forms the basis of their report. Mallampati’s test scores the visibility of pharyngcal structures (faucial pillars, soft palate and uvula) in an attempt to predict difficult tracheal intubation. Three of us used this test as part of a pre-operative asscssmcnt in a study about tracheal intubation. Sainsoon and Young did not make it clear in their paper hut thcy did not make the assessment in the way described by Mallampati. We also chosc to examine our patients with ‘the head in the neutral position’ and the observer sitting ‘opposite at eye level’. We graded paticiits class 1 to 3 as originally described because Mallampati
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Elastodynamic Green's functions of orthotropic half plane
(American Society of Civil Engineers, 1991-03-01) Rajapakse, R.K.N.D; Wang, Y.
The dynamic response of an orthotropic elastic half plane subjected to a set of time‐harmonic buried loadings is investigated. The governing differential equations are established in terms of displacements and a general solution is derived using Fourier integral transforms with respect to the x‐coordinate. The boundary‐value problems corresponding to time‐harmonic vertical and horizontal loads acting in the interior of the half plane are solved. Explicit analytical solutions are presented for displacements and stresses due to buried uniformly distributed and concentrated loadings. Some characteristics of the analytical solution are investigated, and its numerical evaluation is also discussed. Selected numerical results for displacements and stresses of isotropic, ice, layered soil, and cadmium half‐plane regions are presented. A discussion of these numerical solutions is presented to investigate the influence of the degree of material anisotropy, frequency of excitation, and the type of loading on the response of the elastic half plane.
Open Access
A case study on identification and assessment of postharvest losses of tomato (Lycoperisicon escuentum Mill)
(Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 1992) Rupasinghe, H. P. V; Peiris, C. N; Wijeratnam, R. S. W
A study was undertaken to quantify and identify the causes of the postharvest losses of tomato during the Malta season of 1991. In the first phase of the study a suivey was earned out using random samples to collect information on the present system of posthaivest handling of tomato. Four major stages of the posthaivest marketing sequence were identified, namely; fann gate, collection agent, Manning wholesale market (Colombo) and exporter respectively. Loss assessments were conducted at these stages. Tlie survey revealed that pest and diseases such as pod borrer (Heliolhis zea) attack and blight (Altemuiia solani and Pliyiopluliora infestans) are the major contributions for posthaivest losses at the fann gate. Over maturity at hanest, bird attack and losses due to sun scorch were also obseived. Cultivating small extents of land (66% of farmers possess less than half acre) increases the liaircsting interval which resulted in a high percentage of over maturity. Tlie above factors subsequently made considerable losses at the collection agents when soiling the product for transportation. Significant losses were observed al the Manning market due to long distance of transportation with improper handling and transportation. Tlte main problem with exporters was the lack of uniformity of product with respect to maturity and size. Cumulative loss at the Manning wholesale market was obseived to be close to 54%. Contributions to the major causes of loss were as follows; mechanical damage due to over ripening 17.3%, pod borrer attack 23%, blight 4.8% and mechanical damage due to other factors 15%. Tlie cumulative loss and rejections after export quality selection was as high as 96%. Rejects due to non conformity to export specifications with respect to maturity, size and shape were 27.52% and 7.34%, respectively.
Open Access
An evaluation of genetic diversity in micropropagated anthurium using starch gel electrophoresis
(Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 1992) Peiris, S; Mantell, S. H; Peiris, C. N; Senanayake, Y. D. A
Anthurium andreanum Lind is a cut flower which is in high demand in the local and export cut flower trades in Sri Lanka. For commercial production of export anthurium cut flowers, it is essential that the selected elite qualities of the flowers borne on this original mother stock plants are maintained consistantly through many generations on vegetative multiplication. Tliis paper reports on stanch gel electrophoresis which was adapted successfully on anthuriums to evaluate genetic diversity if any, in plants derived either from seedlings, conventional stem cuttings or micropropagated clonal plants. Buffered leaf extracts were compared by means of horizontal starch gel electrophoresis to check the variability in cv. 'Crinkled Red'. Isoenzyme banding patterns of malic dehydrogenase (MDH), 6 phosphogluconic dehydrogenase (6 PGDH), phosphogluco isomerase (PGI) and diaphorase (DIAP) were used. Extracts of 105 seedlings, 60 clonal plants produced through rhizome cuttings and 150 in vitro propagated plants were compared to detect possible somaclonal variations in the daughter plants produced. Results of starch gel electrophoresis showed that extracts of seedling plants contained variations, expressed as percentages showing deviant patterns in all five isoenzyme systems assessed: MDH 14%, 6 PGDH 13%, GOT 12%, PGI 14% and DIAP 16%. None of the clonal plants or in vitro propagated plants tested using this technique showed variations in any of the isoenzyme compared. Tlie results of this study showed the genetic diversity in anthwium seedling plants and confirmed that stability was maintained in vegetatively propagated and in vitro propagated plants. Since in vitro propagation produces a large number of uniform and genetically stable plants, in vitro multiplication would appear to be suitable for use in the Sri Lankan floriculture industry
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Transient response of a circular cavity in a poroelastic medium
(John Wiley & Sons, Ltd, 1993-06) Rajapakse, R. K. N. D; Senjuntichai, T
This paper considers the transient response of a pressurized long cylindrical cavity in an infinite poroelastic medium. To obtain transient solutions, Biot's equations for poroelastodynamics are specialized for this problem. A set of exact general solutions for radial displacement, stresses, pore pressure and discharge are derived in the Laplace transform space by using analytical techniques. Solutions are presented for three different types of prescribed transient radial pressures acting on the surface of a permeable as well as an impermeable cavity surface. Time domain solutions are obtained by inverting Laplace domain solutions using a reliable numerical scheme. A detailed parametric study is presented to illustrate the influence of poroelastic material parameters and hydraulic boundary conditions on the response of the medium. Comparisons are also presented with the corresponding ideal elastic solutions to portray the poroelastic effects. It is noted that the maximum radial displacement and hoop stress at the cavity surface are substantially higher than the classical static solutions and differ considerably from the transient elastic solutions. Time histories and radial variations of displacement, hoop stress, pore pressure and fluid discharge corresponding to a cavity in two representative poroelastic materials are also presented.
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Green's functions for transversely isotropic elastic half space
(American Society of Civil Engineers, 1993-09) Rajapakse, R. K. N. D; Wang, Y
This paper presents a comprehensive analytical treatment of the three‐dimensional response of a transversely isotropic elastic half space subjected to time‐harmonic excitations. General solutions for equations of equilibrium expressed in terms of displacements are derived by applying Fourier expansion with respect to the circumferential coordinate and Hankel integral transforms with respect to the radial coordinate. The general solutions are used to derive the explicit solutions for Green's functions (displacements and stresses) corresponding to a set of time‐harmonic circular ring loads acting inside a half space. The circumferential variation of the ring loads are assumed to be cosmθ for loadings in the vertical and radial directions and sinmθ for the loading in the circumferential direction. These Green's functions can be used as the kernel functions of the boundary‐integral‐equation method and in the development of solutions for a variety of elastodynamic boundary value problems. Comparisons with existing numerical solutions for an isotropic half space are presented to confirm the accuracy of the present solutions. Selected numerical results for displacements and stresses are presented to portray the dependence of the response of the half space on the frequency of excitation and the degree of anisotropy of the medium.
Open Access
Effect of packaging material on the storability of Chillie (Capsicum annum L.) seed in Sri Lanka
(Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 1994) Silva, S. G. R; Peiris, C. N
Extracted chillie seed from ripe, desiccated dry pods of cultivar MI 2 of known germination (81.0%), was dried to 9.7%, 5.9% moisture contents, and packed in three different packaging materials: aluminium foil, 500 gauge polythene and woven polypropylene sacks. The seeds were stored at ambient conditions in Pelwehera (30°C, 80% RH), Rahangala (23°C, 79% RH) and in a cold room (20°C 65% RH) in Gannoruwa. Seed germination, field emergence, and seed moisture content of the stored seed were tested at the inception and at 3 month intervals during the 12 month study period. Chillie seed with a low initial moisture content (5.9%) maintained germinability better than seeds with a high moisture content (9.7%) in all locations. Triple laminated aluminium foil was a better packaging material. Polysack packaging displayed free moisture movement from the early stages of the study, in all the locations. Polythene (500 gauge) was better than polysack and similar to aluminum foil when storing low moisture (5.9%) chillie seed for 12 months, at all the locations except in Pelwehera. A cold room condition was the best to store chillie seed without losing its viability below 75% for a period of one year. It could be recommended that these dried, extracted chillie seed from ripe dry pods of cultivar MI 2 packed in aluminium foil or in polythene (500 gauge) be stored in a cold room (20PC, 65% RH) for a long term (12 months).
Open Access
Identification of cowpea cultivars (Vigna unguiculata (L) Walp) by isoenzyme electrophoresis
(Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 1994) Eeswera, J. P; Peiris, C. N
The differences among cowpea (Vigna unguiculata (L) Walp) cultivars were identified using electrophoretically detected isozymic variability. The enzymes studied in the selected 10 cultivars of cowpea were Diaphorase (DIAP), Phospho Gluco Isomerase (PGI), 6Phospho Gluconate Dehydrogenase (6PGD), Phospho Gluco Mutase (PGM), Esterase (EST), Hexose Kinase (HK) and Glucose Oxalo Acetate Transaminase (GOT). Starch gel electrophoresis was used to analyze extracts prepared from young leaf tissues of seven day old seedlings of each cultivar grown under greenhouse conditions. Three enzymes GOT, HK, and PGM exhibited two patterns, while three different patterns were observed for EST and 6PGD. Phospho Gluco Isomerase showedfour different patterns, and DIAP appeared to be the most polymorphic with eight patterns. Distinct variety specific zymograms were observed for several enzymes. Unique combinations of isozymic variants of two enzyme systems assayed (DIAP and PGI) could differentiate all the culti*urs. Sufficient variability was present in cowpea cultivars to allow the use of isozyme electrophoresis as a method for cultivar identification. Therefore, ii could be used in variety identification to complement the morphological characters.
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Dynamic Green's functions of homogeneous poroelastic half-plane
(American Society of Civil Engineers, 1994-11) Rajapakse, R. K. N. D; Senjuntichai, T
This paper presents a comprehensive analytical and numerical treatment of two‐dimensional dynamic response of a dissipative poroelastic half‐plane under time‐harmonic internal loads and fluid sources. General solutions for poroelastodynamic equations corresponding to Biot's theory are obtained by using Fourier integral transforms in the x‐direction. These general solutions are used to solve boundary‐value problems corresponding to vertical and horizontal loads, and fluid sources applied at a finite depth below the surface of a poroelastic half‐plane. Explicit analytical solutions corresponding to above‐boundary‐value problems are presented. The solutions for poroelastic fields of a half‐plane subjected to internal excitations are expressed in terms of semiinfinite Fourier type integrals that can only be evaluated by numerical quadrature. The integration path is free from any singularities due to the dissipative nature of the elastic waves propagating in a poroelastic medium, and the Fourier integrals are evaluated by using an adaptive version of the trapezoidal rule. The accuracy of present numerical solutions are confirmed by comparison with existing solutions for ideal elasticity and poroelasticity. Selected numerical results are presented to portray the influence of the frequency of excitation, poroelastic material properties and types of loadings on the dynamic response of a poroelastic half‐plane. Green's functions presented in this paper can be used to solve a variety of elastodynamic boundary‐value problems and as the kernel functions in the boundary integral equation method.
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Investment risk concepts and measurement of risk in asset returns
(MCB UP Ltd, 1995-01-01) Alles, L. A
The theory of finance is built around return and risk concepts and a basic tenet of finance is that there is a trade off between the risk and returns of assets. As such the measurement of risk goes to the very core and foundation of the theory of finance. Given that the main theories of finance have been maturing over several decades of discussion and debate, one would imagine that a concept as fundamental as the measurement of risk would be a well settled issue by now. On the contrary, the recent finance literature shows ample evidence that risk measurement and risk concepts are drawing continued scrutiny from academic researchers. This is because there are several alternative, and competing ways in which risk can be conceived of and it is not clear which of the alternative concepts is most appropriate. Each concept of risk can be measured or estimated in several ways as well. Estimation methods can be diverse in their precision. Risk measurement can be further complicated by the fact that risk is not a static feature. Risk changes over time. Whether risk changes can be modelled satisfactorily is a major challenge taken up by researchers.
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Dynamic response of a multi‐layered poroelastic medium
(John Wiley & Sons, Ltd, 1995-05) Rajapakse, R. K. N. D; Senjuntichai, T
An exact stiffness matrix method is presented to evaluate the dynamic response of a multi-layered poroelastic medium due to time-harmonic loads and fluid sources applied in the interior of the layered medium. The system under consideration consists of N layers of different properties and thickness overlying a homogeneous half-plane or a rigid base. Fourier integral transform is used with respect to the x-co-ordinate and the formulation is presented in the frequency domain. Fourier transforms of average displacements of the solid matrix and pore pressure at layer interfaces are considered as the basic unknowns. Exact stiffness (impedance) matrices describing the relationship between generalized displacement and force vectors of a layer of finite thickness and a half-plane are derived explicitly in the Fourier-frequency space by using rigorous analytical solutions for Biot's elastodynamic theory for porous media. The global stiffness matrix and the force vector of a layered system is assembled by considering the continuity of tractions and fluid flow at layer interfaces. The numerical solution of the global equation system for discrete values of Fourier transform parameter together with the application of numerical quadrature to evaluate inverse Fourier transform integrals yield the solutions for poroelastic fields. Numerical results for displacements and stresses of a few layered systems and vertical impedance of a rigid strip bonded to layered poroelastic media are presented. The advantages of the present method when compared to existing approximate stiffness methods and other methods based on the determination of layer arbitrary coefficients are discussed.
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Exact stiffness method for quasi-statics of a multi-layered poroelastic medium
(Pergamon, 1995-06-01) Senjuntichai, T; Rajapakse, R. K. N. D
A method is presented to study the three-dimensional quasi-static response of a multi-layered poroelastic half-space with compressible constituents. The system under consideration consists of N layers of different thickness and material properties overlying a homogeneous half-space. Fourier expansion, Laplace transforms and Hankel transforms with respect to the circumferential, time and radial coordinates, respectively, are used in the formulation. Laplace-Hankel transforms of displacements and pore pressure at layer interfaces are considered as the basic unknowns. Exact stiffness matrices describing the relationship between generalized displacement and force vectors of a finite layer and a half-space are derived explicitly in the transform space. The global stiffness matrix of a layered system is assembled by considering the continuity of tractions and fluid flow at layer interfaces. The time histories of displacements, stresses and pore pressure are obtained by solving the stiffness equation system for discrete values of Laplace and Hankel transform parameters, and using numerical quadrature schemes for Laplace and Hankel transform inversions. Selected numerical results for different layered systems are presented to portray the influence of layering and poroelastic material properties. The advantage of the present method is that for an N-layered system, it yields a numerically stable symmetric stiffness matrix of order 4N × 4N when compared to the unsymmetric and numerically unstable coefficient matrix of order 8N × 8N associated with the conventional method based on the determination of layer arbitrary coefficients.
Open Access
Establishment of embryogenic cell suspension culture of chilli (capsicum annum L. var. accuminatum fingerh) for somatic embryogenesis
(Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 1996) Nandakumar, J; Bandara, J. M. R. S; Peiris, S
Chilli [Capsicum annum L. var. accuminatum Fingerh] is one of the important spice crops ofSri Lanka. Embryogenic suspension cultures of chilli were developed with an objective to induce somatic embryogenesis Successful callus induction was obtained from both leaves and cotyledons of two weeks old seedlings in MS medium containing 1 ppm 2, 4 • D, after incubation in the dark for two to three weeks. A combination ofKinetin (0.x ppm) and 2,4- D (1 ppm) promoted callus proliferation at a high rate. Cell suspension cultures were established using 2 g of four week old leaf and cotyledon calli in 20 ml of liquid MS medium with 1 ppm 2, 4- D in 100 ml Erlenmeyer flasks. Weekly sub culturing was performed. MS medium with 2. 4-D (1 ppm) stimulated embryogenesis on cotyledon callus after 12 weeks in culture. Embryogenic calli formed are pale yellow to brown, compact, organized and nodular in appearance. It comprised of small, richly cytoplasmic cells without large vacuoles. Both initiation of embryogenic cells and the subsequent development of these cells into embryoids occurred in the. same MS (2, 4-D 1 ppm) medium. Within a period of five to seven days, 12 week old, 20 ml of embryogenic cell suspension produced 14 proembryoids After 7-14 days they developed into heart stage and to mature embryoids Plantlet development has not observed until now in the tested MS media, containing activated charcoal, zeatin, IBA and GA3.
Open Access
Robustness of digital filters with respect to limit-cycle behavior under coefficient perturbations
(International Society for Optics and Photonics, 1996-06-07) Kulasekere, E. C; Premaratne, K; Bauer, P. H
A digital filter which has been designed to be limit cycle free may exhibit limit cycles at the implementation stage. This is due to the inability to implement filter coefficients exactly in hardware when they are quantized to satisfy available wordlength requirements. Given a digital filter which is limit cycle free under zero input conditions, the work below presents an algorithm which finds a region in the coefficient space, about the nominal filter coefficient values, where in the filter remains limit cycle free. Furthermore the results of the algorithm will also indicate the availability of other machine representable numbers for the coefficients that fall within this robustness region. Hence one may even choose shorter wordlength registers for coefficient storage if the corresponding grid falls within the constructed robustness region.
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Development of the major triterpenoids and oil in the fruit and seeds of neem (Azadirachta indica)
(No longer published by Elsevier, 1996-09-01) JOHNSON, S; MORGAN, D. E; PEIRIS, C. N
In order to learn the best time for harvesting Neem (Azadirachta indica) seeds, the amount of the five major triterpenoids, together with the oil content have been determined throughout a fruiting season in six selected trees in Sri Lanka. The triterpenoid content and the relative proportions of the major compounds changed little from the hard green fruit stage to mature seeds, while the oil content increased markedly with time. The highest content of azadirachtin (10 mg g-1seed kernels) was recorded in newly ripened seeds. There was some loss of salannin and azadirachtin in storage after harvesting for up to 6 months.
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An exhaustive search algorithm for checking limit cycle behavior of digital filters
(IEEE, 1996-10) Premaratne, K; Kulasekere, E. C; Bauer, P. H; Leclerc, L. J
The presence of limit cycles that may arise in fixed-point arithmetic implementation of a digital filter can significantly impair its performance. This paper presents an algorithm to determine the presence/absence of such limit cycles. For generality, the filter is taken to be in its state-space formulation. The algorithm is applicable independent of filter order, type of quantization nonlinearity, and whether the accumulator is single or double length. It may be utilized to construct limit cycle free regions in filter coefficient space. Once a filter is determined to be limit cycle free, a technique that provides a robustness region in coefficient space where all filters remain limit cycle free is also presented.
Open Access
Yield and quality of tomato as affected by rainfall during different growth stages
(Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 1997) Weerakkody, W. A. P; Peiris, C. N; Jayasekara, S. J. B. A
Cultivation of tomato (Lvcopersicon esculentum) is severely affected during the peak rainy periods in Sri Lanka, which leads to a seasonality in production andfluctuation ofprices. To study the nature of rain damage and to identify the critical growth stages prone to rain damage, staggered planting of tomato was practiced in the Mid Country Intermediate Zone during the Maha season. The rain damage was evaluated in terms of yield components, yield andfruit quality. During the vegetative growth and early flowering, rainfall was positively correlated with yield components andfruit quality. However, rainfall received during the late flowering phase reduced the weight andfinal number of fruits. During fruit growth, rainfall was positively correlated with fruit cracking andjuice pH. A negative correlation existed with other fruit defects. Hence, positive effects cf rainfall during vegetative growth and negative effects ofrainfall during reproductive growth were evident. Late flowering andfruit ripening stages were identified as critical for yield components while fruit growth andfruit ripenug stages were identified as critical for fruit quality.