Evaluation of genomic SSRs and EST-SSRs markers in genetic diversity studies in European Chestnut populations.

Adaptive potential and phenotypic plasticity determine the capacity of the species to adapt to new environmental changes. In this study, six genomic (SSRs) and 11 genic (EST-SSRs) microsatellites markers were used to estimate neutral and adaptive genetic diversity in nine European chestnut populations. These populations were distributed throughout representative areas of contrasting climate conditions in the Mediterranean basin. All neutral SSRs tested were polymorphic for all the populations analysed whereas 9 out of the 11 EST-SSRs resulted polymorphic. Genetic diversity values obtained with genomic SSRs were higher as compared to those obtained with EST-SSRs (Ho=0,60 and Ho=0,32 respectively). Moreover, genomic SSRs showed higher within population gene diversity and lower among population variation as compared to the EST-SSRs. Principal coordinates analysis showed slightly different grouping of the populations for the two types of markers. These preliminary results confirm that combining genomic and EST microsatellites is a useful tool to give complementary information to understand the genetic and adaptive diversity in chestnut.