Hazelnut (Corylus avellana L.) is a strategically important nut crop with high nutritional value and significant economic potential. While industrial cultivation is primarily based on green-leaved genotypes, interest in purple-leaved forms has been steadily increasing due to the ornamental appeal and elevated antioxidant potential associated with anthocyanin pigmentation. However, information on nut morphometric traits and the variability in hybrid populations of purple-leaved hazelnut remains limited. This study aimed to analyse the morphometric characteristics of nuts in a hybrid population of purple-leaved hazelnut developed at the National University of Life and Environmental Sciences of Ukraine. The experimental material included nuts from 23 mature own-rooted hybrid shrubs derived from a cross between ‘Akademik Yablokov’ and ‘Moskovskij Rubin’. Nut and kernel weight, linear dimensions, shell thickness, kernel percentage, and nut shape index were evaluated using standard morphometric and statistical methods. The results revealed substantial phenotypic variability in nut morphological traits, with average nut weight ranging from 1.4 g to 3.4 g. Based on the aggregate of economic traits, the ‘Profesorskyi’ genotype was identified as the most promising overall, producing the heaviest nuts (3.4 g) and kernels (1.6 g). Correlation analysis revealed a strong negative relationship between kernel percentage and shell thickness (r = -0.670), indicating shell thickness as the primary limiting factor for kernel yield. The studied hybrid population represents a valuable genetic resource for hazelnut breeding, enabling the selection of genotypes suitable for both commercial nut production and ornamental use. The combination of high nut quality with pronounced decorative traits associated with stable anthocyanin pigmentation highlights the potential of purple-leaved hazelnut for diversified agricultural production and landscape applications
Mezhenskyj et al. (Fri,) studied this question.