Climate change is reducing yields and altering the flavor of matcha tea in Japan. Growers are turning to genomic selection to identify heat-tolerant plants more quickly. The approach is already part of ongoing breeding programs.
Japan’s hotter nights and erratic spring temperatures are affecting premium tencha leaves, which are shaded and ground into matcha. In the Kyoto-Uji region, spring temperatures have risen by 0.6 to 1 Celsius over the past century, leading plants to produce more bitter-tasting catechins.
Akiko Ogino of the NARO Institute of Vegetable and Tea Science said conventional cultivars are not always performing well under the new conditions. Traditional breeding requires raising thousands of seedlings and waiting up to 15 years to assess traits, with full cultivar registration taking around 25 years.
Genomic selection identifies markers for heat tolerance in seedlings at an early stage. Takashi Ikka of Shizuoka University said the method helps prioritize candidates before long field trials, though it does not replace them. Ogino and Ikka both noted there is no clear genetic link between heat tolerance and bitterness, suggesting breeders can select for both traits.
George Guttridge-Smith of Kyoto Obubu Tea Farms said new research helps but tea farming remains a waiting game.
