Morphological Diversity and Multivariate Analysis of Selected Young Turkish Hazelnut (Corylus colurna L.) Seedlings

OpenAlex Türkçe

Corylus colurna L. (Turkish hazelnut) is a hazelnut species with a single trunk. It can grow to 15-20 meters tall and develops into a tree form. C. colurna L. has significant potential as a rootstock because of its low suckering ability, vigorous growth, deep root system and adaptability to diverse ecological conditions. Its nuts are generally small to medium-sized, with thick shells and relatively low kernel percentages, but they are valued for their distinctive flavor and suitability for certain processing and breeding purposes. Given these agronomic and biological attributes, understanding the extent of morphological variability within C. colurna L. is essential for its effective utilization and selection. Therefore, this study aimed to determine the variation in specific morphological characteristics among C. colurna L. genotypes and to identify relationships among these characteristics using multivariate statistical methods. The research was conducted between 2020 and 2021 on 398 Turkish hazelnut genotypes (C. colurna L.) in a nursery in the Samsun province. The International Union for the Protection of New Varieties of Plants (UPOV) criteria were used to define morphological characteristics. Data were analyzed using correlation analysis, principal component analysis (PCA), and clustering heatmap. Correlation analysis revealed significant positive relationships between leaf length, leaf width, shoot diameter, plant height, and plant diameter, while significant negative relationships were observed between abaxial leaf pubescence and petiolar pubescence and the growth-related traits. Principal component analysis explained 45.32% of the total variation in the studied morphological traits through two principal components, with PC1 mainly associated with leaf size (leaf length and leaf width) and shoot diameter, and PC2 mainly associated with petiole length and number of suckers. Cluster analysis grouped the genotypes into six distinct clusters, indicating substantial morphological diversity in the population, with cluster separation mainly driven by differences in leaf size, shoot traits, and pubescence-related characteristics. In seedlings that were approximately 3 years old at the time of evaluation (originating from 2-year-old material established in the field), 98.7% of the evaluated genotypes did not produce suckers, confirming the suitability of C. colurna L. as a non-suckering rootstock. Overall, the results demonstrate that multivariate analysis of morphological traits is a practical approach for identifying variation and selecting promising genotypes, providing valuable baseline information for future hazelnut rootstock breeding and improvements.