Genetic Diversity Evaluation of Date Palm (Phoenix dactylifera L.) Cultivars in Saudi Arabia Using ISSR Molecular Markers.

الملخص

The date palm (Phoenix dactylifera L.) is a fundamental crop in arid and semi-arid habitats, especially in the Kingdom of Saudi Arabia, where its genetic improvement and preservation are strategically significant. This study examined the genetic diversity of 12 cultivars collected from three major agricultural regions—Al-Ahsa, Al-Kharj, and Al-Qassim—using inter-simple sequence repeat (ISSR) markers recognized for their high polymorphism resolution and reproducibility. The three primers (ISSR-60, ISSR-64, and ISSR-81) generated different and reproducible amplification profiles, indicating significant inter-cultivar variation. Genetic similarity coefficients varied from 0.640 to 0.913, with the greatest affinity identified between Naboot Seif and Wannana and, the least between Hoshishi and both Sabaka and Rothana. Three significant genetic clusters were identified using the UPGMA, which reflected both regional origin and underlying genetic linkages. These findings highlight the usefulness of ISSR markers in detecting genomic polymorphisms and resolving cultivar-level genetic structure, providing vital insights for germplasm management, conservation measures, and the improvement of targeted breeding programs in date palm.