Improved root architecture and seedling performance in pistachio (Pistacia vera L.) via radicle-tip excision

Abstract Background Root system architecture is a key determinant of plant establishment, particularly in species such as Pistachio (Pistacia vera L.), which inherently display limited lateral root formation and low survival rates after transplanting. This study evaluated the impact of radicle-tip excision on root architecture and overall seedling vigor in ‘Ohadi’ pistachio cultivar. A factorial experiment was conducted using five distinct radicle length categories at the time of excision: L1 (0.5–1.0 cm), L2 (1.01–2.0 cm), L3 (2.01–3.0 cm), L4 (3.01–4.0 cm) and L5 (4.01–5.0 cm), and three cutting sizes of 1 mm (CS1), 3 mm (CS3) and 5 mm (CS5) while untreated seedlings were used as the control group. Following radicle-tip excision, the seedlings were grown in perlite-filled pots and irrigated weekly with half-strength Hoagland’s nutrient solution. Growth, vitality, and root architectural traits were assessed at end of the experiment. Result Remarkably, the L3CS3 treatment involving excision of 3 mm from the radicle tip when its length reached L3 (2.01–3.0 cm) resulted in significant enhancements in key morphological traits, including shoot and root fresh/dry weights, leaf area and plant height. In addition, root system characteristics such as the number of lateral roots (NLR), network depth (NWDP), network volume (NWVL), and convex area (NWCA) showed substantial improvement. Ordinal regression analysis revealed a strong relationship between lateral root traits and overall seedling vigor, confirming the physiological relevance of the root manipulation. Complementary correlation analysis further supported the notion that improved root traits positively influence shoot growth, indicating an integrative effect. Conclusion These findings underscore the potential of radicle-tip excision as a cost-effective and scalable approach to improve root functionality and transplant performance in pistachio, with broader applicability to other species that exhibit limited lateral root development in nursery production systems. Graphical abstract