Faculty of Humanities and Sciences
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Publication 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. WA 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.Publication 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. NExtracted 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).Publication 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. NThe 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.Publication Open Access Plant growth flowering and fruit formation of tomato grown under protected culture(Postgraduate Institute of Agriculture, University of Peradeniya: Peradeniya, 1998) Weerakkody, W. A. P; Peiris, C. NProtected culture is a remedy for environmental problems of crop cultivation. However, seasonal weather changes adversely affect indoor grown plants. Therefore, this study was conducted to examine the affect of protected (indoor) culture and other improved technologies, often used in protected culture, on tomato (Lvcopersicon esculentum L.) grown with irrigation during the Maha season. Two indoor cultures together with improved technology and two outdoor (open-field) cultures with and without improved technology were used as treatments. Vegetative and reproductive growth of tomato were evaluated during the respective growth stages. Except at early vegetative growth, dry weather prevailed during the cropping season. Most of the vegetative growth parameters were not significantly different between the indoor and outdoor treatments. However, indoor culture showed significantly higher flowering and fruit formation. The shed house recorded the highest number of fruits per plant. Significantly higher vegetative growth was observed with the use of improved technologies, irrespective of the experimental conditions. Moreover, the improved technologies contributedfor greater number offlowers per plant but not for number of fruits. Indoor culture in combination with the improved technology assured greater vegetative growth, flowering and fruit formation of tomato when compared to outdoor culture under low rainy conditions that prevail during the Maha season. Except for fruitformation, comparative advantages of different indoor structures were not evident.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 Fruit formation, marketable yield and fruit quality of tomato varieties grown under protected culture in two agro ecological zones during the rainy season(National Science Foundation: Colombo, 1999) Weerakkody, W. A. P; Peiris, C. N; Karunananda, P. HEnvironmental limitations in agriculture can be successhlly overcome wit11 the use of protected (indoor) culture. Howevel; the powtll and developme~t of indoor grown crops with pa~tial environmental control vary with season, location and crop genetic dif~"erences. This rescarcll was conducted to study the influence of agro-ecological conditions and varietal differences on fiuit development, yield and fiuit quality of' protected c~~lture grown tomato during the rainy season. The location, Rallangala (upcountry intermediate zone) enhanced the yield components, hit size and damage-free fruits under rainy weatller. Fruits at Peradeniya (midcountry wet zone) had higllcl. tolal soluhlc solids (TSS), fruit acidity and locular material contents compared to Rahangala. Protected culture gave greater iiuit formation, yield (fruit weight and numbcr of'marketahle fruits), f'luit size and damage-free fruits than the open field culture. As a result ofthe interaction between culture and locati.on, the hjghest yield and fruit size were reported at Rallangala while the highest TSS w'as reported at Peradeniya in protected culture. More marketable fiuits of cultivar T-245, Iligl~er f111it weight of cultivar Heat; Master and liiigher yield of cultivar Cariho were found, especially under protected culture. Caribo appeared to he suitable for both regions while Heat Master and T-245 were better adapted to Ral~angala and Pcradeniya, respectively. The polythene llouse with improved technology was more productive usder the agro-ecological conditions at Rallangala duxing MuIra season in terms of yield and external fiuit quality of tomato while it was more suitahle,for Peradeniya during XL~U, season in terms of internal fuit quality of tomato.Publication 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. ACultivation 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.