Effect of habitat conditions of elite Cerasus mahaleb L. genotypes on their progeny characteristics in the Fereydunshahr Seed Orchard, Iran

Background and Objectives: Mahaleb cherry (Cerasus mahaleb L.) belonging to the Rosaceae family is a valuable native tree species of the Irano-Turanian region. Owing to its high drought tolerance and remarkable ability to establish under harsh environmental conditions, it plays an important role in the restoration and conservation of semi-arid mountainous forests. In addition, it contributes to soil stabilization, enhances biodiversity, and serves as a resilient rootstock for fruit trees in horticultural systems. Despite its ecological and economic importance, limited information is available on the phenotypic performance of different genotypes grown under uniform environmental conditions within a common seed orchard. Therefore, this study aimed to investigate the influence of maternal habitat characteristics on the growth and productivity traits of elite mahaleb genotypes established in the Fereydunshahr seed orchard.
Materials and Methods: A total of 120 cuttings representing elite genotypes selected from six natural habitats with contrasting ecological conditions, including differences in elevation, slope, aspect, and soil properties, were evaluated over eight consecutive years in the Fereydunshahr seed orchard. Two important vegetative traits, namely plant height (cm) and canopy diameter (cm), were measured twice annually (spring and summer) during the final three years of the evaluation period. The average values recorded traits in the third year were used as the principal criterion for identifying superior genotypes. In addition, the relationships between vegetative growth traits and ecological characteristics of the maternal habitats, including annual precipitation, temperature, slope, and altitude, were examined using Pearson’s correlation coefficient. Furthermore, hierarchical clustering analysis using Ward’s method was performed to classify the 10 superior genotypes based on their phenotypic performance.
Results: The evaluation of mahaleb genotypes under uniform environmental conditions in the Fereydunshahr seed orchard revealed considerable variation in plant height and canopy diameter over the three-year assessment period. Significant phenotypic differences were detected among the evaluated genotypes, indicating that both genetic and environmental factors of maternal habitats substantially influenced vegetative growth. A very strong positive correlation was observed between plant height and canopy diameter (r≈ 0.96), reflecting a coordinated pattern of vertical and horizontal growth among the superior genotypes. However, there were no significant relationships between either trait and ecological characteristics (annual precipitation, temperature, slope, and altitude. Hierarchical cluster analysis using Ward’s method separated the selected genotypes into two clearly distinguishable groups. Genotypes assigned to Cluster 1 exhibited significantly greater plant height and canopy diameter than those belonging to Cluster 2. These results indicate that, despite cultivation under identical orchard conditions, the genetic background of the genotypes and the environmental characteristics of their maternal habitats continued to exert a pronounced influence on growth performance. The findings provide valuable information for the establishment of improved seed orchards and for the identification of suitable parental genotypes in future breeding programs.
Conclusion: For the establishment of improved seed orchards, it was recommended to combine genotypes exhibiting vigorous vegetative growth with those demonstrating stable and consistent reproductive performance. Such a breeding strategy can facilitate the production of high-quality seeds that are well adapted to diverse environmental conditions. Forest stands established from these improved seeds are expected to possess greater genetic diversity, enhanced adaptability, and increased resilience to environmental stresses, thereby contributing to the long-term sustainability of forest restoration and conservation programs.