Unveiling the Genetic Wealth: Characterization of Wild Hazelnut (Corylus avellana L.) Populations in Düzce Province from Türkiye

This study was carried out in Yığılca, Gümüşova, Cumayeri and Akçakoca districts of Düzce province in 2023. In the study, pomological and morphological characteristics of 129 genotypes in natural hazelnut populations and orchards were determined. Genotypes were distributed in the altitude range of 25-760m, 90.5% were detected in orchards and 9.5% in areas such as roadsides, stream beds and mountain slopes. When the genotypes were grouped in terms of plant height, it was determined that 75.39% were taller than 4 m, 22.24% were between 3-4 m, 1.58% were between 2-3 m and 0.79% were between 1-2 m. In the examined genotypes, nut length was measured between 15.0-25.4 mm, nut width was measured between 14.5-28.1 mm, nut size was measured between 14.19-20.61 mm and nut shape index was measured between 0.75-1.84. Leaf length varied between 8.92-15.36 mm, leaf width between 6.85-12.89 mm, and petiole length varied between 0.5-2.68 mm. While 79.13% of the genotypes have a husk longer than the nut, 66.09% have a husk slit. The number of hazelnut husk, one of the basic elements of yield, was determined to be 3 and above in 50% of the genotypes. In the study, it was evaluated that the hazelnut genetic resources in Düzce have a wide variation and that it is important to protect and use them in breeding studies. It was emphasized that especially genotypes with a nut size of 20 mm and above, round-shaped and number of nuts in cluster is over four in new cultivar development.