Genetic diversity and population structure in Quercus suber L. revealed by nuclear microsatellite markers and generation of a core collection

Cork oak (Quercus suber L.) is an essential species of the Mediterranean region. In Morocco, it represents a source of life and is a noble species for many populations. The Maamora forest, situated in Morocco, is recognized as the largest forest in the Mediterranean basin and displays the highest diversity compared to other forests in its distribution area. This study aimed to establish a genetic database of 240 individuals from Maamora forest using seven SSR markers. Through a series of statistical analyses, we determined the level of diversity and genetic structure and created a core collection. Statistical analysis of the data showed a high degree of allelic variation, generating 47 alleles with an average of 6.71 alleles per locus. Furthermore, a high percentage of polymorphisms and a high Shannon index were observed. Intra-population genetic diversity was found to be high (86%) compared to inter-population diversity (14%). A low level of genetic differentiation (Gst = 0.12) and high gene flow were identified, consistent with the results obtained from the analysis of molecular variance (AMOVA). This suggests a possible capacity for the species to adapt to environmental conditions. A core collection of 18 genotypes was constructed, which included all the private alleles that were detected in this study. This core collection exhibited similar and crucial diversity to that identified in the initial collection, as verified by a series of genetic diversity and structural analyses. This research advocates populations and individuals for further studies on adaptation in order to improve and conserve this valuable resource in the future.