Recent progress of intra-specific hybridization of tea (Camellia sinensis, (L.) O. Kuntze) in Sri Lanka

Tea germplasm accessions are the most valuable material for tea breeding. However its utilization in the past was limited due to lack of available information. Recently generated information on genetic structure and metabolite profiles of the germplasm were used in selecting parents for hybridization programmes from 2012 to 2016. The main focus of the programme was to make crosses between three taxa of tea viz. Camellia. sinensis var. assamica (Assam type), C. sinensis var. sinensis (China type) and C. sinensis spp. lasiocalyx (Cambod type). Pollinated buds were closely-monitored and the number of crosses, number of fruits, number of seeds and reproductive parameters were recorded. A total of 3978 crosses (2405 direct crosses and 1573 reciprocal crosses) were made and 974 seeds were obtained from 595 fruits. Percentages of fruit set and seed set varied significantly among different families. Irrespective of the inter-subspecies groups, the percentage of seed germination was above 50% and was not significantly-different. Cross compatibility between taxa in terms of percentage of fruit set ranged from 4.6% to 25.6% and varied significantly. Among the inter-subspecies crosses the Assam varieties were found to be the best as female parent. The generated information would be useful for selection of parents and tea improvement programmes in the future.