## 4 Discussion  
The 19 CAPS genotype mixtures used were able to classify 23 _C. depressa_ accessions from three regions (Okinawa, Kagoshima, and Taiwan) and revealed their intraspecific variation/uniformity (Table 1 and Figure 2). Accessions from Kagoshima, except \"Tokunoshima 1\", were elicited to be genetically close to each other. Moreover, the accessions were divided into Okinawan and Kagoshima lines, and the outcome agreed with the results of a previous study [9]. The _C. depressa_ cultivar is considered to have Asian Mandarin origins with Okinawan indigenous _C. ryukyuensis_ as parents [18]. Accordingly, \"Tokunoshima 1\" of Kagoshima may have been brought in from the same parents as the Okinawan lines, which were originally cultivated in the main island of Okinawa. Moreover, the Taiwanese accessions \"Nantou\" and \"Taoyuan\" were found to be genetically close to Okinawan accessions. Okinawa and Taiwan are the original distribution sites of _C. depressa_, suggesting that the parents may be closely related [18]. \"Izumi kugani-like\" was found to have many homozygous genetic patterns among the 23 _C. depressa_ accessions. This fact suggests the possibility of \"Izumi kugani-like\" being the pure variation and has different genetic properties from other accessions [10]. In the current study, 12 combinations of CAPS markers/restriction enzymes were found to be effective in differentiating _C. depressa_ cultivars, which is valuable when considering the genetic properties of _C. depressa_. This result also demonstrates that these CAPS marker/restriction enzyme compositions are useful for identifying variations in _C. depressa_ accessions from larger collection sites and other similar small-type citrus cultivars or their hybrid varieties, as they are known to have more intraspecific variety than other citrus fruits in the region [8; 9]. Taken together, _C. depressa_ contains abundant genetic resources based on regional differences, despite the commonality of the accessions. These outcomes provide basic information on the genetic association between the major _C. depressa_ accessions of the cultivar from different cultivation regions (Kagoshima, Okinawa, and Taiwan), which could explain the variations in their phenotypes, including yield, disease resistance, and flavor traits. The identification of _C. depressa_ accessions could also lead to the development of new varieties and an increase in their commercial value. The total content of VOCs in the leaves showed small differences among the different cultivation regions and accessions; however, their VOC profiles varied (Figure 3a,b). As for accessions of Kagoshima, except \"Tokunoshima 1\", the four accessions were commonly rich in thymol methyl ether, piperitone, and (Z)-\(\beta\)-ocimene and were closely plotted to each other on PCA (Figure 3b-d). This outcome agrees with their genetic characteristics (Figure 2), which suggests the possibility of the existence of genetic information that manifests in the production of certain VOCs in leaves and, hence, contributes to their unique odor quality. Meanwhile, on the PCA plot, the Okinawan and Taiwanese accessions differed from Kagoshima accessions (except \"Tokunoshima 1\") as they were plotted around the origin and further to the negative direction of the PC1 axis. The two accessions of Okinawa (\"Kohama\" and \"Tokashiki\") which were located on the PC1 negative direction were revealed to have abundant sesquiterpenes (bicyclogermacrene, \(\alpha\)-copaene, \(\alpha\)-cubebene,  
Figure 6: Volcano plots of VOCs of _C. depressa_ fruit edible parts: (**a**) comparison between Okinawa and Kagoshima accessions; (**b**) comparison between Okinawa and Taiwan accessions; (**c**) comparison between Kagoshima and Taiwan accessions. \(\beta\)-elemene, and \(\delta\)-cadinene), indicating their potential distinct aroma traits which can emit greater green and herbal odor [19]. Among Okinawan accessions, \"Kabuchi-hybrid\" was uniquely abundant in \(\gamma\)-muvurolene, suggesting that it can generate a more citrusy-oily odor [20].