Large-Scale Volatile Profiling of 292 Tea Germplasms Reveals Terpenoid Diversity and Regional Aroma Biomarkers

Volatile organic compounds (VOCs) are key determinants of tea quality, yet their large-scale variation among diverse germplasms has not been systematically characterized. In this study, 292 representative tea germplasms were analyzed using HS-SPME-GC-MS. Regional comparisons and receiver operating characteristic analysis highlighted heptanal and neophytadiene as robust biomarkers for distinguishing China's four major tea-growing regions. Leaf-type comparisons showed that medium- and small-leaf germplasms had higher total terpenoid levels, whereas large-leaf germplasms were enriched in limonene, linalool, <i>E</i>-β-ionone, and camphene. Random forest modeling further identified camphene, citral, and allo-ocimene as candidate biomarkers for differentiating leaf types. Geographical variation analysis revealed that Chongqing germplasms exhibited the highest total terpenoid content but the lowest Shannon diversity index (<i>H</i>'), while Guangdong germplasms had the lowest terpenoid content but the highest <i>H</i>'. These findings not only uncover the extensive diversity of VOCs in tea germplasm collections but also provide valuable molecular resources for germplasm differentiation and aroma-oriented breeding strategies.