Genetic structure and diversity of European chestnut (Castanea sativa Mill.) populations in western Balkans: On a crossroad between east and west

• Main Authors: Skender Azra, Kurtović Mirsad, Pojskić Naris, Kalamujić-Stroil Belma, Hadžiabulić Semina, Gaši Fuad
• Format: Article
• Language: English
• Published: Serbian Genetics Society 2017-01-01
• Series: Genetika
• Subjects: genetic differentiation; European chestnut; introgression zone; microsatellites; refugia
• Online Access: http://www.doiserbia.nb.rs/img/doi/0534-0012/2017/0534-00121702613S.pdf

European chestnut (Castanea sativa Mill.) is highly valued in the western Balkans as a source of timber and fruit, but also as an important source of nectar and pollen for the production of honey. In this study, four chestnut populations, covering a major portion of the western Balkans, and a reference population from the northern Italy were examined using 21 microsatellite markers. The highest genetic diversity was detected within the populations geographically closest to the Italian Peninsula, which also displayed the highest level of admixture with the samples from Italy. The strongest genetic differentiation was noted among the southern and eastern chestnut populations from Bosnia and Herzegovina (B&H) (Gst=12.05%). This pronounced differentiation is probably caused by the genetic adaptations to notably different climatic conditions present in the south (Mediterranean climate) and east (Continental climate) of B&H. The clear genetic differentiation of the southern and eastern B&H chestnut populations from the Italian population, determined by pairwise Gst, FCA and Bayesian Structure analyses, indicates that these populations most likely originated from independent shelter zones (refugia), after the last glaciation period. Based on these results we propose a presence of an introgression zone in the northwestern Balkans, established through gene flow from the Italian and the Balkan Peninsula. The obtained insights into the structure of all analyzed populations will significantly contribute towards establishing a regional conservation and utilization strategy for European chestnut in western Balkans.