Molecular Analysis of the Genetic Olive Patrimony Cultivated in the Tunisian Arid Regions

Olive trees represent the main tree cultivated in Tunisia, and farmers prefer to plant this species in marginal lands because of its high adaptability to harsh climates. Thus, genetic analysis of this species can reveal specimens resistant to abiotic stress and allow their valorization in olive tree genetic improvement programs. The study objective is to examine the genetic diversity of olive resources in the country's arid lands and create a molecular database for their genetic profile. In this case, we selected the most polymorphic microsatellites for the species Olea europea L. to analyze the genetic fingerprinting of eight olive varieties cultivated in the south of Tunisia. The markers produced 66 different alleles varied from five for DCA3 and DCA18 to ten alleles per locus for DCA16. Except for DCA17 and DCA18, the tested SSR markers were highly polymorphic with an observed heterozygosis, (Ho) which passed from 62 to 100% with a mean value of 76%. The molecular analyses confirmed the richness of the olive polymorphism in southern Tunisia. PCAo and tree analysis segregated the eight varieties into three main groups, which proves the existence of three main genetic pools. The genetic profiles of these varieties will be valued for the genetic improvement of the Tunisian olive heritage to strengthen their tolerance to abiotic stresses and establish a predictive genetic matrix of future climate changes.