Abstract
Elucidating the genetic control of total phenolic content and antioxidant activity in apricot is essential for breeding programs aimed at developing cultivars with enhanced nutritional quality and health-promoting properties. However, knowledge about inheritance patterns, heterosis effects, and reciprocal cross influences on these biochemical traits in apricot remains limited. We investigated the genetic transmission, heterosis, and phenotypic variation of total phenolic content and antioxidant activity in F1 populations derived from reciprocal crosses between ‘İmrahor’ and ‘Hasanbey’ apricot cultivars. Both cross combinations and parental genotypes significantly influenced all measured parameters (p ≤ 0.001). Both F1 populations exhibited negative mid-parent heterosis for total phenolic content (−20.05% to −24.31%) and antioxidant activity (−13.69% to −32.62%), with the majority of F1 individuals (80.77% to 100%) falling below the lower parent value. Reciprocal cross effects were particularly pronounced for antioxidant activity, with İmrahor (♀) × Hasanbey (♂) producing F1 individuals with significantly higher antioxidant capacity (203.33 μmol TE·100g−1 FW difference, p < 0.001) compared to the reciprocal cross, demonstrating strong maternal effects. Principal component analysis revealed that PC1 explained 92.8–94.3% of total variance, indicating a strong positive correlation between phenolic content and antioxidant activity. Despite overall negative heterosis, substantial phenotypic variation among F1 individuals (CV: 11.76–18.12%) enabled identification of superior genotypes, with A13, A15, and A25 ranking highest in the İmrahor × Hasanbey population. We conclude that while both traits show predominantly additive genetic control with negative heterosis in these cross combinations, significant transgressive segregation and maternal effects provide valuable opportunities for selection of elite individuals with enhanced antioxidant properties. The quantitative genetic parameters and phenotypic distributions identified offer valuable insights for marker-assisted selection and breeding strategies targeting improved nutritional quality in apricot.