## 3 Results and Discussion
### Principal Component Analysis  
To analyze comprehensively the changes in antioxidant activities influenced by genotype and different plant tissues, a principal component analysis (PCA) was performed on the entire dataset (data obtained from four antioxidant assays in 40 methanolic extracts). Specifically, the PCA was conducted to identify the representative genotypes and tissues within each of the three genotype groups (Orte 1 and Orte 2 populations, and reference genotypes) that exhibited the most significant antioxidant activities (FRAP, ABTS, DPPH) and total phenolic content (TPC). The first two principal components (PC1 and PC2) cumulatively accounted for a total explained variance of 82.05% (Table S2). Specifically, PC1 explained 65.62% of the total variance, and included contributions from the ABTS and FRAP assays, along with TPC (Table S2). PC2, on the other hand, explained 16.43% of the total variance and was correlated with the DPPH assay (Table S2). The PCA scores effectively separated the different samples into distinct groups, facilitating the interpretation of results based on all the examined antioxidant assays. Based on PC1, which explained the larger part of the total variance, it is possible to distinguish two distinct groups of samples with negative and positive PCA scores on the left and right sides of the PCA biplot (Figure 27). The first group included samples with lower antioxidant activities, as measured by ABTS, FRAP, and TPC, and was represented by all leaf samples and predominantly by the PFH samples. The second group comprised samples with higher ABTS, FRAP, and TPC values, represented mainly by SFH and stem samples. On the other hand, PC2 distinguished between these two main groups by discriminating samples with higher and lower DPPH values, located in the upper and lower parts of the graph, respectively (Figure 27). These results clearly indicated that, in most genotypes, the highest antioxidant activities and total phenolic content were found in the stem and SFH tissues among the four plant tissues tested. This is consistent with information available in the literature regarding the antioxidant properties of different artichoke plant parts. For example, studies by [PERSON] and colleagues [?? ] analyzing two artichoke germplasm collections, comprising cultivated  
Figure 1: PCA biplot on antioxidant activities (FRAP, ABTS, DPPH) and total phenolic content (TPC) across the different genotypes and tissues. In the biplot, leaf tissues are represented in green, primary flower heads (PFH) in purple, secondary flower heads (SFH) in orange, and stem tissues in blue. and wild _Cynara cardunculus_ genotypes, showed that the stem exhibited higher antioxidant capacity, measured by the FRAP and DPPH assays, compared to other arithcoke plant parts, including leaves, receptacles, and inner and outer bracts. Furthermore, [PERSON] et al. [2 ] reported that the secondary flower heads of the cultivar Green Globe demonstrated higher scavenging capacity, as measured by the DPPH assay, than the primary flower heads. The PCA biplot also facilitated the selection of genotypes and tissues exhibiting the highest antioxidant activities by considering their close association with the direction and strength of the eigenvectors of the four antioxidant assays. Within the three genotype groups, Orte 1 F4 P10, Orte 2 F7 P2, and Grato 1 emerged as the most promising for their antioxidant activities, especially in the stem and secondary flower head (SFH) tissues, confirming the results of the ANOVA (????????). Specifically, in both the stem and SFH tissues of Orte 2 F7 P2, and in the SFH of Orte 1 F4 P10, a close alignment with the ABTS and TPC eigenvectors was detected (Figure 3), indicating high phenolic content and ABTS radical scavenging ability in these genotypes and tissues. Orte 1 F4 P10 also exhibited significant antioxidant capacity in the stem, which was well-represented along the FRAP eigenvector, confirming its high reducing power.