Wild almond related species (subgenus Amygdalus in Prunus genus, Rosaceae family) are considered as valuable genetic resources which can be used to broaden the genetic background and to introduce new traits into commercial relatives. The current research was conducted to describe the phenotypic variability of three wild almond related species including Prunus haussknechtii Bornm., P. elaeagnifolia Spach, and P. orientalis Mill. from natural habitats. There were considerable variations among the accessions studied of each species. The range of nut weight was 0.44–1.80 g in P. haussknechtii, 0.24-0.78 g in P. elaeagnifolia, and 0.25-0.99 g in P. orientalis. Principal component analysis (PCA) indicated 17 principal components (PCs) with explaining 79.58% of total variance in P. haussknechtii, 14 PCs with explaining 89.54% of total variance in P. elaeagnifolia, and also 14 PCs with explaining 89.45% of total variance in P. orientalis. The generated dendrogram based on the combined data obtained from the three species studied showed two different major clusters and indicated high morphological diversity among and within the studied species. Results showed that the studied wild species are suitable candidates for breeding objectives of almond, such as developing rootstocks with resistance to drought and also developing late-flowering cultivars. The current investigation provided basic genetic information and a reliable basis that should facilitate attempts to protect the species studied for in situ conservation.
