## 4 Conclusions  
This study revealed significant regional variations in the quality of SDT. Cluster analysis of non-volatile compounds categorized the samples from 13 regions into two distinct groups--L1 (SH, GFZ, WLS, BD, DBS, DG, and PS) and L2 (BDao, XN, MA, MN, BKN, and BS)--characterized by sweet mellow and strong taste profiles, respectively. Notably, the TP/FAA ratio was significantly upregulated in the L2 group compared to the L1 group. Similarly, cluster analysis of key volatile aroma-active compounds classified the samples into C1 (PS, BD, DBS, BS, BDao, and DG) and C2 (XN, BKN, SH, GFZ, WLS, MA, and MN) groups. The C1 group exhibited dominant tender and floral aromas, whereas the C2 group was characterized by clean-sweet and honey-like aromas. Comparative analysis demonstrated significant upregulation of floral compounds, specifically geraniol and jasmone, in the C1 group, while the C2 group showed significant downregulation of isophorone (woody), 2-pentyl furan (caramel), 1-octanol (fatty), D-limonene (fruity), and benzaldehyde (fruity). Correlation analysis identified altitude and soil phosphorus content as key factors influencing regional differences in SDT flavor quality. Altitude and available phosphorus (AP) content exhibited positive correlations with floral compounds, as well as with rutin, myricetin, kaempfer, CA, and EC in SDT. Conversely, negative correlations were observed with woody, caramel, fatty, and fruity characteristics, as well as with the bitter and stringent compound EGCG. SDT cultivated in high-altitude regions with elevated AP content demonstrated enhanced sweet mellow characteristics and greater enrichment of floral aroma compounds. These findings provide scientific data supporting the study of regional flavor characteristics in Yunnan SDT. Phosphorus content plays a critical role in regulating SDT aroma compounds, although its underlying mechanisms require further investigation. Future research should focus on achieving targeted regulation of SDT's regional flavor profiles through controlled variable experiments and multi-omics approaches. This study contributes to a deeper understanding of the factors influencing SDT quality and offers a foundation for optimizing cultivation practices enhancing flavor characteristics. Conceptualization, investigation, methodology, and writing--original draft preparation, M.Z. ([PERSON]) and X.D. ; methodology, Q.W. and Z.W. ; formal analysis, X.W. and W.Y. ; resources, L.L. and M.Z. ([PERSON]); data curation, W.L. and S.L. ; visualization, Q.W. and X.W. ; writing--review and editing, Y.S. ; funding acquisition, B.W. All authors have read and agreed to the published version of the manuscript. This research was funded by the Yunnan Tea Industry Artificial Intelligence and Big Data Application Innovation Team (202405 AS350025); the research and development and demonstration project of data sensing technology and equipment for high-altitude mountain smart agriculture (202302 AEO9002001); the study on the screening mechanism of phenotypic plasticity characteristics of large-leaf tea plants in Yunnan driven by Abased on data fusion (202301 AS070083); the Yunnan Menghai County Smart Tea Industry Science and Technology Mission (202304B090013); and the Yunnan Provincial Department of Science and Technology, Joint Agricultural Project (202401 BD070001-043). Incompliance with the \"Ethics Review Measures for Life Sciences and Medical Research Involving Humans\" issued by the National Health Commission of China in 2023 (Document No. 4), specifically Article 32, our study qualifies for exemption from ethical review as it does not present any potential risk to the participants. This study involves a sensory evaluation of food taste using healthy food products without additives. It does not collect sensitive personal data or involve commercial interests. All participants were adults, and their data were anonymized. Participants were fully informed and provided written consent prior to participation, with the option to withdraw at any time.