Background Selection breeding is a fundamental approach to the improvement of plant species, enabling the utilization of individuals with superior traits from the natural genetic diversity for targeted purposes. The Hassa district of Hatay province, located in the Eastern Mediterranean region of Türkiye, lies within the boundaries of the historical Levant region and hosts a rich population of wild olive (Olea europaea L. subsp. oleaster) genotypes. In this study, 20 wild olive genotypes selected from this region were evaluated for their potential as rootstocks, with an emphasis on conserving genetic resources. Domat, a well-known olive cultivar, was used as the scion reference for grafting compatibility evaluations. Results Morphological assessments revealed that scion lengths among the genotypes ranged from 19.78 ± 15.57 (genotype 31.8.2.36) to 56.67 ± 7.84 cm (genotype 31.8.16.14). Principal component analysis indicated that the first three components explained 82.5% of the total variation. A statistically significant correlation was observed between rootstock diameter and scion diameter (r = 0.46, p < 0.05). Anatomical and histological analyses demonstrated healthy scion development and callus tissue formation in several genotypes, including 31.8.2.19, 31.8.2.34, 31.8.5.18, 31.8.16.5, 31.8.16.12, 31.8.16.13, 31.8.16.14, 31.8.23.2, 31.8.27.5, 31.8.27.16, and 31.8.27.17. In combinations involving genotypes such as 31.8.2.26, 31.8.2.38, 31.8.16.07, 31.8.16.11, 31.8.16.16, and 31.8.23.04, the necrotic layer was effectively absorbed by the callus without disrupting vascular connections, enabling the proper formation of conduction bundles. For genotypes 31.8.2.24, 31.8.2.36, 31.8.2.39, and the control Gemlik rootstock, a dense necrotic layer was detected between the scion and rootstock. However, this did not hinder the formation of vascular connections or conduction bundles. Conclusions The findings of this study provide valuable insights into the morphological, anatomical, and histological characteristics of wild olive genotypes, highlighting their potential as rootstocks in breeding programs. These results will support breeders and researchers in the effective utilization and conservation of olive genetic resources.
