A comparative study of the growth, yield, and physiological responses of arbosana, arbequina, coratina, and maraqi olive cultivars

Expanding olive cultivation into newly reclaimed sandy soils faces challenges from salinity, low fertility, and limited water-holding capacity. Success depends critically on cultivar selection, yet comparative information remains limited. This study evaluated four olive cultivars ('Arbosana', 'Arbequina', 'Coratina', 'Maraqi') in Egypt's Wadi Al-Natrun region over two seasons (2024-2025) using a randomized complete block design with four replications. Measurements included vegetative growth, physiological stress indicators (SPAD, RWC, proline), reproductive traits, yield components, fruit properties, and oil content. Significant genotypic variation (p < 0.001) revealed three distinct performance profiles. 'Coratina' showed the most vigorous growth (canopy volume: 8.2-8.5 m³) and highest yield (21.2-22.5 kg tree⁻¹) and oil content (51.0-52.0%), but exhibited lowest RWC (68.8-75.4%), highest proline (12.5-14.2 µmol g⁻¹ FW), and lowest fruit set (0.9-1.2%). 'Arbequina' and 'Arbosana' showed constrained growth (3.1-3.6 m³) but maintained high RWC (78.9-87.2%), low proline (3.1-6.5 µmol g⁻¹ FW), superior fruit set (3.3-4.2%), and highest yield efficiency (3.6-3.8 kg m⁻³). 'Maraqi' displayed intermediate growth (5.6 m³) with highest RWC (86.2-88.5%) and lowest proline (2.8-3.0 µmol g⁻¹ FW), but yield efficiency was low (2.8 kg m⁻³) and fruit set declined 21.4% in the second season. Significant Cultivar × Year interactions indicated differential environmental sensitivity. No single cultivar is universally superior; optimal selection depends on matching performance profiles to production goals, orchard design, and resource availability.