An article published in the journal “Agrobiodiversity” reports the results of a genetic study of the tea plant of the Chinese island of Hainan that indicates that this type of the Camellia sinensis species has an origin that is independent from the other varieties. A team of researchers performed a complete DNA sequencing of the Hainan tea plant to compare it with the DNA of the other types. Knowing the origin of this type of tea offers, among other things, useful indications for its conservation and improvement of its cultivation.

Hainan Island has a long history of tea cultivation thanks to its tropical climate that favors the growth of this and other plants. However, most studies on the Hainan tea have been conducted within more general research on the tea plant. The consequence is that until now the information has remained decidedly incomplete.

A genetic study on the variety called assamica of the Camellia sinensis species whose results were published in the journal “Molecular Plant” in May 2017 showed the complexity of genetic analysis of tea plant. That’s because the tea plant’s DNA turned out to be much larger than expected with just over three billion base pairs, more than four times as many as the coffee plant. The result was the assembly of a high-quality genome named Yunkang 10 by its creators.

The great similarity between Hainan tea and the assamica variety hindered the understanding of the origins and specific characteristics of Hainan tea. This new study changed the situation with a considerable effort, as about 500 samples were taken from Hainan tea trees from four important tea-producing regions of the island. A total DNA sequencing was performed to obtain complete information on the genome of this type of tea plant.

The researchers created a phylogenetic tree that includes Hainan tea and the assamica and sinensis varieties using the Yunkang 10 genome obtained from the study published in 2017 as a reference. The result was the discovery that Hainan tea exhibits a unique genetic composition compared to the other varieties even though the similarities with the assamica variety exist at the genetic level as well.

The genetic uniqueness of Hainan tea offers a potential resource for future breeding programs. It’s one of the goals of the various genetic studies conducted over the years on the different varieties of the tea plant. Certain climatic requirements for its growth have been known for millennia but each new information helps to better understand the possibilities of expanding its cultivation and creating types that are more resistant to pests and diseases. Over time, attempts have been made to grow the tea plant in colder climates but the plants tested can have significantly different characteristics from normal ones.

Even regular tea drinkers tend to take its availability in so many different types for granted. However, behind this availability there’s a work that has become increasingly sophisticated also at the scientific level. Today, in addition to agricultural work there are these genetic studies that could even lead to an expansion of the availability and types of existing tea.