Morphological variation in blackthorn (Prunus spinosa L.) populations in the Northwestern part of the Balkan Peninsula - Absence of geographical and environmental structure

Blackthorn (Prunus spinosa L., Rosaceae) is a deciduous, insect-pollinated, and animal-dispersed shrub or a small tree that naturally occurs throughout Europe. The aims of this study were to describe fruit morphological variability of natural populations in the northwestern part of the Balkan Peninsula and to determine the impact of geographical and environmental conditions on shaping the species’ variability. In total, ten fruit and stone morphological traits were studied using data from twelve natural populations. e obtained data was analyzed using descriptive and multivariate statistical methods. High morphological variability was determined both among and within the studied populations. However, our study revealed no clear eco-geographical differentiation of the studied populations. High morphological variability of the populations, but also the absence of geographical and environmental structuring of populations, could be attributed to the animal-mediated dispersal of fruits over greater distances, combined with the vegetative regeneration and high levels of seed flow among populations, as well as the influence of founder effect. Based on the conducted research, valuable information on intra- and interpopulation variability of fruits’ morphological traits was obtained, which can be useful in creating the guidelines for conservation, breeding, and afforestation programs.