Morus alba var. nigra is one of the most consumed fruit for its special taste and its nutritional and medicinal properties. In the current investigation, the morphological variation of 110 genotypes of this species was evaluated. Most of the traits exhibited significant differences among the studied genotypes. Tree growth habit in most of the genotypes was upright and the main part of evaluated genotypes showed high density for the canopy. Leaf length ranged from 43.85 to 155.62 mm; while leaf width varied from 45.41 to 147.61 mm. Fruit length ranged from 13.08 to 28.68 mm and fruit width varied from 8.35 to 17.06 mm. Fruit weight ranged from 0.75 to 5.02 g with an average of 1.54 and also fruit taste was sweet in the majority of genotypes. Fruit weight showed positive correlations with tree growth habit, tree growth vigor, and leaf dimensions. The Ward dendrogram reflected similarities and dissimilarities among the genotypes and identified two main clusters with several subclusters. Finally, 18 genotypes were superior in terms of fruit characters and are valuable gene pools for breeding programs. Such variations in phenotypic traits provide the possibility to choose populations/genotypes for domestication, breeding, and industrial uses and recommend for the effective conservation strategies.
