Fifteen (15) samples of different date palm cultivars were collected from different locations in Al-Ahsa oasis in the eastern province of Saudi Arabia. Extracted proteins from these samples were analyzed by electrophoresis, and clustered according to the average linkage between groups hierarchical clustering method. The results reveal high degree of similarity based on Jaccard`s similarity method on the basis of presence and absence of bands, that ranged between 0.421 to 0.917, which was represented by phylogenetic dendrogram in six clusters. The closely related cultivars "Hel" and "Hat" in addition to "Khl" represent the sixth cluster, which is separated out of other cultivars with high degree of similarity that ranged between 0.636 to 0.714; it was confirmed by the first principal component with high loading (52.3%), and characterized by four bands (92, 100, 205 and 108 kda). These bands were mostly positioned close to each other in the scatter diagram. The second principal component with loading of 15.7%, which were represented by three bands 19, 25, and 37 kda, have been confirmed the first cluster of closely related cultivars "Shi" and "Shl", as well as the closely related cultivars "Mj" and "OmR" among the second cluster. It can be concluded that most of Al-Ahsa oasis date palm cultivars were from one genetic origin, however, each cultivar was grown from seed of locally known cultivar, and later was selected due to preferred fruit characteristics. More biochemical and molecular studies would be necessary to uncover the genetic relationships between area cultivars.
Key words: SDS-PAGE, bands, phylogenetic, cluster, dendrogram, similarity, principal components.