Early Morpho-Physiological and Biochemical Indicators of Graft Compatibility in ‘Sakıt 6’ Apricot on Plum Rootstocks

Abstract Identifying successful graft unions and developmental interactions between apricot scions and plum rootstocks is critical for enhancing orchard yield and adaptability. This research assessed multiple combinations to determine the most suitable rootstocks for ‘Sakıt 6’ apricot. We investigated morphological, physiological, anatomical, and biochemical parameters of ‘Sakıt 6’ apricot grafted onto multiple plum rootstocks, with evaluations conducted at 300, 650, and 720 days after grafting (DAG). The rootstock genotype had a significant effect on morphological, physiological, anatomical and biochemical traits. The combinations ‘Sakıt 6/63B62’, ‘Sakıt 6/63B11’, and ‘Sakıt 6/63B33’ consistently demonstrated superior graft compatibility, with ‘Sakıt 6/63B62’ achieving the highest histological compatibility score and starch accumulation below the graft union, along with the lowest MDA levels (indicating minimal oxidative stress). ‘Sakıt 6/Myro29C’ exhibited the highest budding success rate and chlorophyll content, while ‘Sakıt 6/63B63’ showed outstanding morphological development with the highest plant height, scion diameter, and rootstock diameter at 720 DAG. In contrast, ‘Sakıt 6/63B16’ and ‘Sakıt 6/63B43’ consistently showed poor compatibility, with ‘Sakıt 6/63B16’ recording the lowest histological compatibility score and demonstrating concerning biochemical markers, including the highest MDA content and peroxidase activity below the graft union. Based on preliminary findings, we conclude that rootstock selection critically influences ‘Sakıt 6’ apricot graft compatibility and performance, with 63B62, 63B11, and 63B33 emerging as superior choices for commercial orchards. The quantitative differences in anatomical, physiological, and biochemical responses between graft combinations provide valuable insights for rootstock breeding programs and orchard management strategies.