Flower Color and Seed Coat Color as a Phenotypic Marker: Correlations with Fatty Acid Composition, Antioxidant Properties, and Metabolite Profiles in Safflower (Carthamus tinctorius L.)

Safflower (<i>Carthamus tinctorius</i> L.) is a versatile oilseed crop valued for its adaptability, high oil quality, and antioxidant properties. This study investigates the influence of flower color (FC) on the phenotypic diversity of 172 safflower accessions, analyzing agronomic traits, metabolite profiles, and antioxidant capacities. Frequency distribution, effect size, principal component analysis (PCA), and network analysis were employed to elucidate trait associations and interrelationships. FC significantly impacted traits such as oleic acid (OA), linoleic acid (LA), oleic desaturation ratio (ODR), and N-feruloylserotonin (FS), with large effect sizes (η² > 0.16). Medium effects were observed for 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) scavenging capacity, palmitic acid (PA), and flowering date (FD). PCA and network analyses highlighted relationships between FC and other fatty acid and antioxidant traits. Qualitative traits such as seed coat color (SCC) and thorn of involucre (TI) also showed significant associations with FC, underscoring its role as a phenotypic marker. These findings provide a robust framework for trait-based breeding strategies in safflower and emphasize the need for further genetic validation of these associations.