In the present study, 30 male and female genotypes were selected from seedling trees originating from open pollination of five pistachio cultivars (‘Akbari’, ‘Badami’, ‘Sarakhs’, ‘Kirmizi’, and ‘Siirt’) to investigate factors associated with the juvenile and adult growth phases in pistachio and to identify genotypes characterized by a short juvenile period. The genotypes were evaluated for vegetative and reproductive traits. The results revealed a wide range of variation in the morphological traits and juvenile periods among the studied genotypes. The S16-4 genotype, parented by the ‘Siirt’ cultivar, was characterized by white nuts and a green kernel. It exhibited the shortest juvenile period among the studied genotypes. Among the male genotypes, BZ11-3 displayed the longest flowering period (21 days) and favorable yield, while the S16-2 genotype, distinguished by its upright growth habit and relatively long flowering period (13 days), was also notable. Correlation analysis between vegetative and reproductive traits indicated that, in female genotypes, rachis length was positively correlated with leaf length and leaf width . In male genotypes, pollen weight showed a negative correlation with the number of leaflets and a positive correlation with shoot length . Based on the results of this study, it can be postulated that a shorter juvenile period in pistachio trees was associated with more efficient reserve utilization and greater dry matter accumulation. Therefore, factors such as larger leaf dimensions, and higher leaf area that promotes vegetative growth and increases storage capacity of carbohydrate may contribute to a reduction in the juvenile period.