Characteristics of New Yellow-Green Color Leaf Tea Germplasm

The purpose of this study was to report the growth traits and chemical composition of yellow-green leaf tea plants germplasm (Ku1), which was discovered in Gurye-gun, Jeollanam-do, Korea. Ku1 exhibited a shrub-like growth form and a medium-leaf variety. The color of its one bud and three leaves at the first harvest time was yellow-green. The chlorophyll content of Ku1 was much lower than that of the green leaf tea plant cultivar, Sangmok (SM). The total amino acids and theanine contents in one bud and three leaves of Ku1 at the first harvest time were 25.02 ± 0.34 and 16.06 ± 0.43 mg/g DW, respectively, which were 0.66 and 0.59 times lower, respectively in Ku1 compared to SM. However, the total polyphenol and total catechin contents in Ku1 were 231.1 ± 3.65 and 147.06 ± 0.73 GAE mg/g DW, respectively, which were 1.3 times and 1.2 times higher, respectively in Ku1 than in SM. Notably, the contents of epigallocatechin gallate and epicatechin gallate in Ku1 were 92.03 ± 0.32 and 22.38 ± 0.13 mg/g DW, respectively, and were thus 1.8 times and 1.4 times higher in Ku1 than in SM. In conclusion, the ‘Ku1’ tea plant variety with yellow-green leaves is a tea germplasm distinctly different from the green leaf tea plant cultivar SM and is characterized by lower amino acid content but significantly higher levels of total polyphenols, total catechins, EGCG, ECG, and caffeine. This study suggests that the yellow-green tea variety ‘Ku1’, which is rich in polyphenols, especially EGCG, could be a valuable tea plant germplasm. This could be useful for diversifying tea types and promoting tea consumption, and plant sources for the food and health functional food industries.