A global consortium on tea genetic resources will benefit tea-growing countries around the world, according to Professor Liang Chen, curator of the world’s largest collection of tea diversity and co-author of the Crop Trust’s Global Strategy for the Conservation and Use of Tea Genetic Resources.
Dr. Chen, who curates the China National Germplasm Hangzhou Tea Repository at the Tea Research Institute of the Chinese Academy of Agricultural Sciences (TRICAAS), is a leading expert on tea germplasm in CAAS’s Agricultural Science and Technology Innovation Program, expertise he brought to the strategy, which sets out high-priority actions needed to develop a secure and cost-effective global conservation system for tea diversity.
“The tea conservation and research community need to work together,” Dr. Chen said in a conversation with the Crop Trust. “We need to align our conservation methods and agree on how to make the most of these collections.”
What is the focus of the work on tea diversity in China?
In China, tea diversity is considered to have inestimable potential for the future of our tea industry.
The China National Germplasm Hangzhou Tea Repository conserves more than 3,000 accessions of tea germplasm, including all the species and varieties of the Section Thea of the genus Camellia. Approximately half of the accessions have been evaluated using a multidisciplinary approach including taxonomic classification, agronomic traits, cup tea quality, pest resistance, molecular diversity and other criteria.
In 2011, we also established a core collection of 360 accessions of Chinese tea germplasm, which is important for the effective management and use of tea diversity in breeding programs. We hope to confirm the center of origin of tea using whole-genome resequencing. To conduct this research, obtaining diversity from southwest China and neighboring countries is crucial. However, this is very difficult from outside those countries.
What are the main challenges you have identified in your work and in the strategy?
I always knew it would be challenging to develop a truly effective global strategy. This is because tea genetic resources include not only the tea plants themselves but also related data, and every country has its own policies and rules on access to these things. This also makes it very difficult to guarantee adoption of the strategy.
For our work in China, we need more germplasm from India, but accessing these materials is not easy, even though we experts in this field know each other. We also need materials from Myanmar, maybe Vietnam, and also Nepal and Laos, areas around the southwestern border of China. It is easier to organize sharing materials of a cereal crop like rice, than of tea, unfortunately.
We do have exchange programs with countries like Kenya, but it is still difficult to share germplasm freely. I believe sharing data will be much easier than sharing germplasm. Establishing international quality standards for collecting and maintaining tea germplasm will also be possible, if there is funding and experts to organize the work.
What is the highest priority in the strategy?
To me, the highest priority is to establish a universally accepted list of descriptors for the tea plant. Having a standard descriptor list is critical. The International Plant Genetic Resources Institute, now called Bioversity International, issued its “Descriptors for Tea” in 1997. In China, we published the “Descriptors and Data Standards for Tea” in 2005.
I believe it is now time for the top global scientists on tea genetic resources to come together to establish universal descriptors for tea genetic resources based on these previous efforts. A set of common, agreed-upon descriptors will allow all tea researchers and curators anywhere in the world to characterize genetic resources and, thereby, assess diversity and pinpoint unique materials within and among different collections.
What are the next steps?
First, we must share the strategy findings. The China Tea Science Society and TRICAAS were planning to host the 2020 International Tea Conference in Hangzhou, but it was postponed to 2021 because of COVID-19. We will also suggest an international consortium to work on the descriptors and data sharing.
I am proud of the work we did with the strategy. We needed such a global approach. Now, the tea conservation and research community need to work together to implement it. I know we cannot guarantee that all actors will come together but, if we can organize two-thirds of them, that would be a success.
Now that the strategy has been published, a global consortium on tea genetic resources will hopefully become a reality. I am sure that this will help us align our conservation methods and unify how we make the most of these collections.
What do you like most about your work?
I am over 50 years old now, but I still like to go to the fields, to the mountains, in search of wild tea plants and then take back branches or seeds to preserve and evaluate them. I do this not only for conservation purposes but also to use the diversity. That makes me very happy. I will spend the remaining years of my professional life—fewer than 10 years now—working on the collection, both conservation and research. For some time now, one of my wishes has been to have 100 graduate students, preferably from tea-growing provinces in China. They can then continue my work after I retire.
Are you close to reaching those 100 students?
No. Maybe half [laughs]. But in all seriousness, we do need more scientists and more funding to continue maintaining the wild tea genebank for more research, which will ultimately lead to better tea.
Development of the Global Strategy for the Conservation and Use of Tea Genetic Resources was led by the Crop Trust in collaboration with TRICAAS, several other key national collection holders and the consumer goods company Unilever. Read the Strategy summary here and a previous Q&A with Strategy co-author Dr. Paula Bramer on saving tea.