## 4 Discussion
Okinawan accessions were plotted along the PC2 axis distributing from the PC2 positive to negative direction, as Kagoshima fruits shared the positions on the PC2 negative direction, indicating that some of Okinawan accessions such as \"Hijakunibu\", \"Ishikunibu\", \"Katsuyama kugani\", \"Kohama\", and \"Ogimi kugani\" might have a similar composition of volatiles to fruits of Kagoshima origins (Figure 5c,d). Through the loading plot, relationships were found between esters and aldehydes in the Okinawan and Kagoshima fruits, respectively. Kagoshima accessions and Okinawan \"Kabuchi-hybrid\" could be identified from the other accessions on PCA analysis, and the result agrees with the results from the PCA analysis of the leaves (Figure 3). Conversely, although the Taiwanese accessions had high levels of VOCs in their fruits, there was no correlation with the leaf VOC profiles, which indicated that the two plant sections had distinct metabolic pathways for producing secondary metabolites, such as volatile constituents [24; 25]. The VOC markers of _C. depressa_ fruits that identified each cultivation region were discovered through the OPLS-DA plot as follows: aldehydes for Kagoshima, esters for Okinawa, and monoterpenes for Taiwan (Figure 5e,f). Furthermore, the volcano plots identified significant region-specific VOCs: Kagoshima was rich in aldehydes such as hexanal, heptanal, octanal, and nonanal; Okinawa in methyl butanoate, methyl hexanoate, methyl octanoate, and ethyl hexanoate; and Taiwan in terpinolene, \(\gamma\)-terpinene, \(\beta\)-myrcene, alloocimene, and \(\beta\)-pinene (Figure 6, Supplementary Table S4). These compounds and physicochemical traits of _C. depressa_ fruits might influence their sensory properties. For instance, juices made from the fruit edible parts of Taiwanese accessions with high VOCs concentration could contribute to their overall citrusy aromas, followed by green and herbal stents, whereas juices made from fruits of Okinawa and Kagoshima accessions would be associated with a fruity aroma (Supplementary Figure S1). In addition, Okinawa and Kagoshima accessions were discovered to contain more sugar than Taiwanese fruits, with greater soluble solid/titratable acidity ratios being observed; hence, Taiwanese fruits could be distinguished by their strong sourness, whereas Okinawa and Kagoshima fruits would be regarded as sweeter [2; 17]. In contrast, the Taiwanese accessions contained more amino acids [17]. The overall flavor of fruits can vary considerably owing to variations in the characteristics of volatile compounds and metabolites, as well as variations in accessions and cultivation environments. The results of VOC profiles of _C. depressa_ fruits provide valuable information that can be applied to the manufacture of beverages and processed foods with distinct flavor properties. For instance, Kagoshima and Okinawan fruits are best used for fresh consumption or are processed into juices, whereas the rich aroma of Taiwanese fruits can be used as a base ingredient for producing various processed foods and beverages. Furthermore, combining fruits of different origins can result in a new type of _C. depressa_ product that is more akin to the preferences of both producers and consumers. The current study mainly explored the genetic characteristics and VOC profiles of the major accessions of Japanese and Taiwanese _C. depressa_; however, other minor accessions of the cultivar in these regions require further investigated. Future studies should investigate the flavor characteristics and sensory properties of processed food products manufactured from _C. depressa_ fruits, such as beverages.