Multilevel evaluation of Prunus cerasifera Ehrh. rootstock candidates on nutritional and biochemical networks in ‘Hacıhaliloğlu’ apricot

Understanding rootstock-mediated physiological and biochemical traits is critical for selecting stress-resilient apricot genotypes. However, integrated assessments of mineral nutrition, oxidative balance, hormone profiles, and carbohydrate metabolism in grafted systems remain limited. We evaluated mineral uptake, oxidative stress responses, antioxidant enzyme activity, hormone content, and sugar profiles in ungrafted apricot rootstock candidates and in 'Hacihaliloglu' cultivar grafted onto 13 Prunus cerasifera genotypes. Genotypic variation was significant across all parameters. Particularly, 63B69, 66B14 and 63B16 and its grafted combination (H/63B69, H/63B14 and H/63B16) consistently exhibited superior nutrient accumulation, lower oxidative damage (H₂O₂, MDA), higher antioxidant enzyme activity (CAT, SOD), and favorable hormonal and sugar profiles. Multivariate and correlation analyses revealed that grafting reorganized the physiological network, enhancing integration between mineral nutrition, antioxidants, and hormones. Notably, H/63B69, H/63B14 and H/63B16 formed a distinct cluster with high values for beneficial traits, suggesting efficient nutrient uptake and stress mitigation capacity. These findings indicated the critical role of genotype-specific rootstock selection in enhancing the physiological, biochemical, and nutritional performance of apricot trees, particularly under adverse environmental conditions such as drought and heat stress. The consistent superiority of certain genotypes (e.g., 63B69, 66B14, 63B16 and its grafted combination H/63B69, H/63B14 and H/63B16) across multiple functional traits, including nutrient uptake efficiency, antioxidant defense capacity, osmoprotectant accumulation, and hormonal balance, demonstrates that rootstock choice is not merely a supporting factor, but a decisive determinant of overall plant resilience and adaptability. Therefore, strategic utilization of well-characterized rootstock genotypes tailored to specific stress profiles represents a promising approach for improving orchard sustainability and productivity in the face of climate-induced challenges.