Browsing by Author "Kottawa-Arachchi, J. D."

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Assessment of selected biochemical parameters in a hybrid population of tea to predict the quality of processed tea
(4th International Research Symposium on Pure and Applied Sciences, Faculty of Science, University of Kelaniya, Sri Lanka, 2019) Abeysekara, R. M. U. N.; Kottawa-Arachchi, J. D.; Ranathunga, M. A. B.; Amarakoon, A. M. T.
Tea is made from the processed leaves of the mature tea plant, Camellia sinensis L. It is one of the most popular beverages in the world. Tea breeding programs constantly attempt to improve the yield and quality of tea by producing new cultivars. Biochemical and molecular markers are frequently used to assist the conventional tea breeding techniques. Chlorophyll a, b, total chlorophyll, carotenoids and total polyphenol content in tea leaves can be used as biochemical markers to predict the quality of processed tea. In this study, young shoots of 112 individuals from a hybrid progeny which was derived from TRI 2043 and TRI 3055 through controlled hybridization in Tea Research Institute of Sri Lanka were analyzed for chlorophyll a, b, total chlorophyll and carotenoid content. 102 individuals from the hybrid population were analyzed for total polyphenol content. Acetone (80%) extraction was used for the analysis of pigments and methanol (70%) extraction was used for the analysis of total polyphenol. Spectrophotometry (absorbance at 470 nm, 646 nm, 663 nm and 765 nm for chlorophyll a, b, carotenoids and total polyphenol respectively) was used with relevant standards for quantification. Statistical analysis (Minitab16 to determine frequency distributions using histograms and boxplots, SAS 9.1 to prepare dendrogram in cluster analysis) of the results had shown wide segregation of the measured parameters and some of the off springs had recorded higher values than the parents. According to the results, highest chlorophyll a content were recorded in accessions 134, 16 and 67 (3.25 mg/g, 3.10 mg/g and 2.92 mg/g respectively) and chlorophyll b in accessions 134, 16 and 67 were also higher than the others in the population (1.21 mg/g, 1.13 mg/g and 1.02 mg/g respectively). The total chlorophyll content in accessions 134, 16 and 67 were recorded as 4.46 mg/g, 4.23 mg/g and 3.95 mg/g respectively. Carotenoid content in accessions 77, 98 and 36 were higher than the others in the population (2.46 mg/g, 1.63 mg/g and 1.10 mg/g respectively). The highest total polyphenol content (33.13%) was recorded in parent TRI 3055. Total polyphenol contents in accessions 94, 72, 95, 92 and 102 were higher than the rest of the progeny (32.51%, 31.33%, 31.10%, 30.87% and 30.28%). Measured parameters of the hybrid population were subjected to cluster analysis. The resultant dendrogram clearly categorized the progeny into four clusters. Accessions with higher chlorophyll, carotenoid and polyphenol contents (accessions 150, 52, 35,134 and 16) could be candidates for the development of new cultivars with better quality tea
Morpho-molecular genetic diversity and population structure analysis to enrich core collections in tea [Camellia sinensis (L.) O. Kuntze] germplasm of Sri Lanka and India
(Genetic Resources and Crop Evolution, 2023) Kottawa-Arachchi, J. D.; Ranatunga, M. A. B.; Sharma, R. K.; Chaudhary, H. K.; Attanayake, R. N.; Amarakoon, A. M. T.; Gunasekare, M. T. K.; Sharma, B.; Kumar, N.; Sood, V. K.
Despite tea [Camellia sinensis (L.) O. Kuntze] is one of the top non-alcoholic beverages consumed around the world; its genetic and phenotypic diversity is less understood compared to other plantation crops. The study’s aims were to undertake phenotypic and genotypic characterization of Sri Lankan and Indian tea germplasm and to identify diverse accessions to accelerate tea breeding programmes in both countries. A total of 171 tea accessions, comprising 94 Sri Lankan and 77 Indian accessions were used. All the accessions were subjected to phenotyping and genotyping using 28 polymorphic simple sequence repeat (SSR) markers. Based on 16 morphological characters, the first three principal components explained 57.61% and 58.43% of the total variability of Sri Lankan and Indian accessions, respectively. Young shoot pubescence, young shoot pigmentation, serration of leaf margin, and mature leaf colour contributed positively to the grouping of accessions. Based on Neighbor-joining analysis, all Sri Lankan accessions grouped in a single cluster, whereas Indian accessions grouped in two distinct clusters. The Gower’s distance method was the most appropriate than other methods for developing core subsets. Among 21 Sri Lankan core accessions selected, 11 accessions belong to introductions, five TRI-developed cultivars and five estate selections. Among 18 Indian core accessions selected, 11 belong to China types, two Assam types and five Indian recommended cultivars. The current study is the first study to compare tea germplasm of both countries and the results are useful for tea crop improvement programme, conservation and utilization of tea germplasm in India and Sri Lanka in the future.
Variation of catechin and caffeine content in exotic collection of tea [Camellia sinensis (L.) O. Kuntze] in Sri Lanka and potential implication in breeding cultivars with enhanced quality and medicinal properties
(Food Chemistry Advances, 2022) Kottawa-Arachchi, J. D.; Ranatunga, M.A.B.; Amarakoon, A.M.T.; Gunasekare, M.T.K.; Attanayake, R.N.; Sharma, R.K.; Chaudhary, H.K.; Sood, V.K.; Katoch, R.; Banyal, D.K.; Piyasena, K.G.M.P.; Edirisinghe, E.N.U.
Tea leaves are rich in diverse metabolites with medicinal importance. The quality of made tea is largely depended on the qualitative and quantitative attributes of key metabolites. The aim of the present study was to quantify flavan-3-ols and caffeine of exotic tea germplam and explore the medicinal properties. Fresh leaf flavan-3-ols; catechin, epicatechin (EC), epicatechin gallate (ECg), epigallocatechin (EGC) and epigallocatechin gallate (EGCg), caffeine and gallic acid of 131 accessions (87 exotic and 44 improved cultivars) were performed by High Performance Liquid Chromatography. Variations in metabolites among cultivars as well as between seasons were determined. Among the flavan-3-ols, EGCg was the most abundant followed by EGC, ECg and EC. Hierarchical clustering of 131 accessions based on metabolite diversity resulted two major clusters. Indian introductions clustered with well-known high quality cultivars indicating the potential utilization of high quality black tea production. Exotic accessions with low caffeine contents (< 20 mg g−1) were grouped separate cluster indicating the promising genetic resources for the development of low caffeine tea. Present study revealed that selected exotic tea accessions rich in bioactive compounds such as catechins and caffeine content could be utilized in producing speciality teas with enhanced quality and medicinal properties.