Genetic diversity, chemical constituents and anatomical analysis of eight popular Olive (Olea europaea L.) cultivars in Al-Jouf region, Saudi Arabia

In light of the multitude of olive trees cultivated and the lack of the genetic diversity of available
genotypes to select varieties and lines that are characterized by high diversity and better performance
under the corresponding conditions, A comparison analysis of the genotyping and morphological
characteristics of eight olive cultivars growing in Saudi Arabia’s Al‑Jouf region was conducted and
analyzed. Morpho‑anatomical and chemical characteristics along with both inter‑simple‑sequence
repeats (ISSRs) and start‑codon‑targeted (SCoT) markers were used to evaluate the genetic diversity
among eight olive varieties in Al‑Jouf, Saudi Arabia. Analyses of 27 morphological, chemical, and
anatomical characteristics concluded the existence of genetic differences among the studied varieties.
Moreover, six ISSR and eight SCoT primer combinations produced a total of 48 loci, of which 18 (10
ISSR and 8 SCoT) were polymorphic. The average polymorphism information content (PIC values of
0.48 and 0.44, respectively) and marker index (MI of 0.79 and 0.48, respectively) detected for ISSR
and SCoT markers revealed the prevalence of high genetic diversity among the studied olive varieties.
Based on chemical and anatomical characteristics and the selected molecular markers, the eight
olive cultivars were grouped into two distinct clusters. Clusters in the adjacent joint dendrogram
produced using ISSR, SCoT and combined data were similar, and grouped all individuals into two
groups. However, the dendrogram generated on the basis of SCoT separated individuals into
subgroups containing at least two varieties. The findings showed that both methods were effective
in assessing diversity, and that SCoT markers can be used as a reliable and informative method for
assessing genetic diversity and relationships among olive varieties and can serve as a complementary
tool to provide a more complete understanding of the genetic diversity available in Olea europaea
populations in Saudi Arabia.