Genetic differentiation and gene flow between wild and cultivated Prunus avium: An analysis of molecular genetic evidence at a regional scale

Abstract

The presence of conspecific wild-type and cultivar populations has been a common landscape feature for centuries. As orchards generally continue to expand towards the natural forest, two important issues are raised: the potential reduction of cultivar genetic diversity compared to wild populations and the extent of gene flow between the two population types. These questions were addressed in a study of Prunus avium in northern Greece using nine simple sequence repeat loci to analyse genetic variation in 93 wild-type individuals and 21 cultivars representing the local cultivated germplasm. Results showed a significant reduction of genetic diversity parameters in the cultivated germplasm compared to natural populations. Bayesian, frequency-based and Markov chain – Monte Carlo analyses have revealed that the wild and cultivar groups are genetically divergent and that realized between-group gene flow is almost completely absent. This result was further verified by a principal component analysis showing a clear separation of the two groups in low multivariate space after a principal coordinate analysis. The significant disjunction in flowering time and a considerable geographic distance between the two groups could primarily account for the absence of substantial gene flow. These findings indicate that local wild cherry can provide a source of genetic variation for future breeding in the genetically restricted cultivar group.

Keywords::

• Admixture analysis
• Bayesian clustering
• sweet cherry
• SSR
• wild cherry

Acknowledgements

This research has been co-financed by the European Union (European Social Fund – ESF) and Hellenic national funds through the Operational Program “Education and Lifelong Learning” of the National Strategic Reference Framework (NSRF) – Research Funding Program: Heracletus-II. Continuous support for the Institute of Agrobiotechnology/CERTH from the General Secretariat of Research and Technology of Greece is also acknowledged. We also acknowledged the comments made by anonymous reviewers since the comments critically improved the manuscript.

Figure 1 A principal coordinates analysis (PCOORD) in the wild cherry and sweet cherry (cultivar) groups based on the molecular variation of SSR genetic markers.

Notes

^† These authors contributed equally to this work.