Mahasen A B Ranatunga
Tea Research Institute of Sri Lanka,Sri Lanka
Mahasen Ranatunga is a Principal Research Officer at the Plant Breeding division of Tea Research Institute of Sri Lanka, Talawakelle, Sri Lanka. He obtained his BSc (Agric.) Hons Degree from Faculty of Agriculture, University of Peradeniya. Later he earned a MSc in Biotechnology from Tamil Nadu Agricultural University, India and PhD (Plant Sciences) from the Post Graduate Institute of Science, University of Peradeniya. His expertise and current research interests are in tea breeding, molecular biology and biotechnology. He has authored 02 boook chapters, 20 research articles in peer reviewed journals and over 40 research communications and abstracts. He is a recipient of Presidents awards for Scientific Publication in 2009.
The role of tea germplasm in crop improvement, though well recognized, yet lack sufficient information depriving its optimum use. About 600 accessions are conserved as tea germplasm and only 4% has been frequently utilized in breeding. The core collection captures the total genetic diversity of germplasm into a manageable size to enable utilization. The study was conducted to assemble a core collection of tea germplasm, using a holistic approach to facilitate management as a field genebank and to increase utilization in breeding.
A representative sample of 93 accessions from the total collection was grouped based on the floral, biochemical and molecular diversity. The stepwise clustering in combination with random, preferred and deviation sampling strategies was employed in selection of entries to the core collection. The final core was selected based on the differences of traits between core collections and the germplasm evaluated using the coincidence rate (CR%) for range and the variable rate (VR%) for the coefficient of variation.
Five major groups were identified based on floral traits and accessions were categorized into three major types China, Assam and Cambod using pistil traits elucidating that the collection predominantly represented by Cambod followed by Assam types. Contents of proline, theanine and theobromine showed wide variations and dendrogram constructed using biochemical characters identified five major clusters. Six SSR primers generated 46 alleles with an average Polymorphism Information Content of 0.71. Fourteen - potential core collections were constructed and the collection developed using biochemical parameters and preferred sampling method was found to be the best with highest CR% of 102.25 and high VR% of 101.55.
The study assembled the first core collection of tea germplam in Sri Lanka with 64 accessions to represent the total diversity which would facilitate the management with minimum cost, time and space.