Little attention has been paid to indigenous plum accessions and their distribution in many parts of Iran despite their importance as genetic resources and sources of germplasm. In this study, we used morphological and pomological characteristics to elucidate the phenotypic diversity of 79 autochthonous plum (Prunus domestica L.) accessions. Significant differences were observed among the accessions based on all of the studied characters. Fruits ripened from 23 July to 22 September. Fruit skin color ranged from yellow to black, with the predominant skin color being black. Fruit weight ranged from 4.97 to 42.19 g (average 17.23 g). Fruit flesh thickness varied from 5.70 to 17.16 mm. Fruit weight showed significant and positive correlations with leaf and fruit dimensions, and a negatively significant correlation with tendency to suckering. Principal component analysis showed that fruit-related characters were the most effective traits for differentiating the studied accessions. The Ward dendrogram revealed the similarities and dissimilarities among the accessions with identifying two major clusters. In terms of productive traits and fruit quality, the fruits of some accessions can be used for processing and drying and those of others can be freshly consumed. Finally, the results of this study provide information on the morphological and pomological characteristics of indigenous plum accessions that could be used in the conservation and management of this valuable genetic resource and also applied in plum breeding programs.
