Retain VP teas while grooming new seedling variety - TRI

by Gamini WARUSHAMANA

The Tea Research Institute (TRI) has introduced new improved seeds which have higher yield potential comparable to VP tea, pest and disease tolerance characters as a source of planting material. TRI Director, Dr. Sarath B. Abeysinghe said that the new seedling tea is a significant achievement in research for adaptation of the tea industry to the adverse impact of climate change.

Tea was first introduced to Sri Lanka 140 years ago and at that time the only planting material were seeds brought from China or India.

The yield was low and bushes were different to each other. The positive characters were aroma, the high quality of tea and drought resistance nature due to tap root and main root systems.

In the 1950s Vegetatively Propagated (VP) teas were introduced with high yield and other characters such as even bushes, pest and disease resistance. The TRI 2000 series is the first VP generation introduced to different climatic zones. For instance, TRI 2025 was suitable for up country, TRI 2024 up-country and the Uva, TRI 2023 and 2026 for low country.

The new improved varieties, TRI 3000 and 4000 series were introduced later using conventional breeding with further high yield potential and incorporating or improving other characters. Average yield of seedling tea is around 800-1000 kg/he and it increased to 2000-2500 kg/he in TRI 2000 series. In TRI 3000 and 4000 series the potential yield is 4000-5000 kg/he.

This is the optimal potential under conditions such as good soil and best plantation management practices.

However, VP teas are vulnerable to adverse impacts of climate change such as shift in agro-climatic zones, productive lands becoming unproductive, drought, heat stress and unforseen pest and disease outbreaks due to change in ecological spread of pest and pathogen populations. This new improved seedling tea is an effective adaptation measure that minimise these risks, Dr. Abeysinghe said.

Seedling tea is better drought resistant due to tap root and hard nature of its roots and therefore is a best option for tea plantations in the Uva region which is most vulnerable to the drought. Regional Plantation Companies (RPCs) which manage tea and rubber plantations can start tea seed gardens and seedling tea nurseries. TRI has introduced the technology but cannot commercially supply seedling tea plants to meet the huge demand. Seed gardens should be maintained in isolation, in rubber estates, to avoid pollination.

In the development of high yield seeds we used VP series as parental plants. Different combinations were used to incorporate different characters and there are biclonal and policlonal seed varieties developed at several seed gardens in different climatic zones. Another advantage of seedling tea, is that it helps to improve genetic diversification of tea Dr. Abeysinghe said.

He said that at the beginning plantation companies were not interested in this field-testing but after seeing the results, today, there is a huge demand for seedling. The shifting to new improved seedling tea is crucial for the long term sustainability of the tea industry. However, our advice to the growers is to maintain a combination of seedling and VP teas in their plantations.