Browsing by Author "Alwis, L. M. H. R."

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    Morphological Characterization of Newly Improved Tea (Camellia Sinensis L. 0. Kuntze) Cultivars
    (Uva Wellassa University of Sri Lanka, 2012) Ruwanpura, U. D. R. E.; Ranatunga, M. A. B.; Alwis, L. M. H. R.
    Improved tea cultivars is one of the key determinants in facing emerging challenges of the tea industry such as high cost of production, declining land productivity, yield fluctuation due to adverse climatic effects and maintaining quality and quantity of the end product. In line with the breeding priorities Tea Research Institute (TRI) has developed its next series of cultivars which is going to be available for commercial planting in the near future. Agronomic trait evaluation of nine elite cultivars selected for up country tea growing region has completed and it is intended to characterize them for morphological descriptors before releasing them. Hence, this study was conducted with the objective of characterizing newly improved tea cultivars using internationally accepted standards and to distinguish the discriminating morphological attributes which are useful in identification of cultivars. This study was also aimed to formulate a vivid description of newly improved cultivars by preparing a cultivar catalogue
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    Protocol for callus induction of Camellia japonica L. (Tea rose)
    (Uva Wellassa University of Sri Lanka, 2015) Dilrukshika, H. L. T.; Alwis, L. M. H. R.
    Camellia japonica (the Japanese Camellia) is one of the best known species of the genus Camellia. Among the Camellia species, the economic value of the C. japonica ranks the highest due to its beautiful ornamental flowers, edible uses (dried flowers, oil), medicinal uses (astringent, antihaemorrhagic, haemostatic, salve and tonic) and material uses (dye, oil) (Salinero et al., 2012). Although C. japonica has a high ornamental and medicinal value, it is not popular in tea cultivating tropical agricultural country like Sri Lanka yet. Further, it was revealed that the difficulties of propagating Tea Roses are significant and therefore growers discourage to propagate them. Also C. japonica multiplication and improvement through seeds is rare due to poor seed set in the white and pink varieties present in Sri Lanka. C. japonica is usually propagated only using stem cuttings in Sri Lanka at present. But rooting was very poor in both pink and white varieties (Fernando and Alwis, 2013). But a good economic potential can be achieved in Sri Lanka due to its beautiful ornamental flower which is having long life span if it is scientifically developed to get different colors and shapes. Therefore, it is very important to in vitro propagation of C. japonica in large scale to commercially enhance its real value especially in the up country and mid country regions of Sri Lanka. Therefore this study was aimed to develop a protocol to induce the callus culture of Camellia japonica L (Tea Rose). Material and Methods This research study was conducted at Tissue Culture laboratory at Uva Wellassa University during the period of 22.04.2014 to 15.08.2014. The explants were collected from the Ury estates in Balangoda Plantations and Hakgala Botanical Garden, Hakgala, Nuwara Eliya. This study was conduct to develop an efficient protocol for rapid and prolific callus induction of Camellia japonica (Tea Rose). In the first experiment, leaves and nodal segments used as explants. Nine different combinations of 20% sodium hypochlorite for three different time durations (20 minutes, 30 minutes, 40 minutes ) and 70% ethanol for three different time durations (30 seconds, 1 minute, 1 and half minutes ) were used to select the best sterilization method. Number of contaminated vessels were counted after one week. Above nine treatment combinations were succeeded only for C. japonica leaves. Because of again used another nine different treatment combinations for surface sterilization of nodes by adjusting soaking time duration in the 20% sodium hypochlorite (35 minutes, 40 minutes, 45 minutes). In the second experiment, leaves, nodal segments and un opened flower bud flower petals used as explants. The sterilized explants were cultured on MS medium with three different hormone combinations of 3-indolebutric acid (IBA) and 6-benzylamino purine (BAP) to investigate the effect on callus induction.
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    Study on response of rice varieties to different nitrogen fertilizer levels
    (Uva Wellassa University of Sri Lanka, 2015) Priyadarshanee, H.V.C.; Alwis, L. M. H. R.; Sirisena, D.N.
    Rice (Oryza sativa L.) is the single most important crop and the staple food of more than three billion people or more than half of the world’s population. Paddy is cultivated as a wetland crop in all districts. Direct or indirect involvement for paddy sector is more than 30 % of the total labour force (Wickramasinhe and Wijewardena, 2000). Rice provides 45% total calorie and 40% total protein requirement of an average Sri Lankan (Department of Agriculture,2010).The areaunder paddy production in yalaand maha was 1,671,054 Mt and 2,629,566 Mt respectively (Department of Census and Statistics, 2010). Nitrogen, phosphorous and potassium are the three major nutrients required for the rice plant. Nitrogen (N) is one of the essential macro -nutrients for rice growth and one of the main factors to be considered for developing a high-yielding rice cultivar. Nitrogen increases plant height, panicle number, leaf size, spikelet number, and number of filled spikelets, which largely determine the yield capacity of a rice plant. Panicle number is largely influenced by the number of tillers that develop during the vegetative stage. Rice plants require nitrogen during the tillering stage to ensure a sufficient number of panicles and reproductive to grain filling. Nitrogen imbalance in soil produces low fertilizer use efficiency, low yields and low farmer profit.Main nitrogen loss mechanisms are volatilization of ammonia (NH3), leaching loss of nitrate (NO3-), loss through denitrification and soil erosion (Choudhury and Kennedy, 2005).Therefore, optimum level of nitrogen fertilizer should be applied to get maximum yield of paddy cultivation and utilize nitrogen fertilizers effectively (Fageria and Baligar, 2003). Materials and Methods This study was conducted at the Rice Research Development Institute (RRDI) at Batalagoda in Kurunagala district, Sri Lanka. Fertilizers used were urea as the Nitrogen source, and others; Triple super phosphate and Murate of Potash. The experiment was comprised with sixteen treatments. Nitrogen fertilizer was applied as 0, 50, 100 and150 kg N ha-1. Four rice varieties, Bg 1350 (V1), Bg 997 (V2), Bg 379-2 (V3) and Bg 450 (V4) were tested. These four rice varieties are in age group of four to four and half months.Sixty four plots were arranged according to the split plot design with sixteen treatments and four replicates. Plant height, number of tillers per hill, plant greenness, number of days for 100 % flowering of rice varieties, dry weight of shoot parts, plant nitrogen content, number of panicles per hill and grain yield were measured against different nitrogen levels. As the results showed (Table 1) there was a significant effect (P<0.005) among the treatments for the plant height, number of tillers per hill, plant greenness, number of days for 100 % flowering of rice varieties, plant nitrogen content, number of panicles per hill and grain yield. There is no statistically significant difference among the levels of nitrogen and variety with dry weight of shoot parts.