Understanding the genetic relationships and breeding patterns of Sri Lankan tea cultivars with genomic and EST-SSR markers

Sri Lanka is the second largest global tea exporter. Genetically diverse planting material are vital in adjusting for biotic and abiotic stresses. Accordingly, sixty four tea cultivars, which represent the entirety of the recommended cultivars consisting of 50 improved cultivars and 14 Estate selections were analyzed at 33 Genomic and EST-SSR loci with the objective of assessing the genetic diversity and population structure of cultivated tea in Sri Lanka. Genotypic data were subjected to cluster and population structure analysis using power marker and Structure software. The results revealed three groups in the dendrogram and the population structure was described at the level of three sub-populations; the main sub-populations deriving from a single Assam type tea plant and the other two from old seedling teas and the hybrids between the above sub-populations. The cultivated tea in Sri Lanka were thus revealed to be of vary narrow genetic base dominated by the Assam type tea of Indo-Chinese origin. In conclusion, it is urged for enhancing the genetic diversity of the cultivated tea by incorporating exotic China type tea germplasm and more parents from old seedling teas grown in Sri Lanka in the breeding programme.