Mulberries (Morus spp., Moraceae family) contain nutritional and medicinal values, and may help reduce cholesterol, blood sugar, and cancer risk. The present study aimed to investigate the phenotypic variation of black mulberry (Morus nigra L.), white mulberry (M. alba L.), and M. alba L. var. nigra and to select the promising accessions for cultivation in orchards. Analysis of variance showed significant differences for all traits among the investigated accessions, thus indicating the existence of high phenotypic variation among the examined accessions. Fruit weight in M. nigra ranged from 2.61 to 5.55 g, in M. alba ranged from 1.27 to 2.75 g, and in M. alba var. nigra ranged from 1.06 to 4.93 g. Fruit weight showed positive and significant correlations with leaf length (r = 0.61), leaf width (r = 0.74), fruit length (r = 0.85), fruit width (r = 0.92), and fruit weight (r = 0.91). Principal component analysis (PCA) showed that traits were placed into two main and independent components accounting for 73.72% of the total variance. Cluster analysis divided the accessions into two main groups, the first group included the accessions of M. nigra, while the second group included the accessions of M. alba and M. alba var. nigra. Based on fruit quality related characters, such as fruit weight and total soluble solids, accessions no. 28, 15, 25, and 16 in M. nigra, accessions no. 16, 11, 14, 5, 20, and 3 in M. alba, and accessions no. 16, 10, 7, and 26 in M. alba var. nigra were promising and can be used for cultivation or in mulberry breeding programs due to their larger fruits with better taste.
