Natural biochemical and morphological diversity of oleaster (Elaeagnus angustifolia L.) genotypes from the west of Iran: applicable for conservation, domestication, and breeding

Oleaster tree ( Elaeagnus angustifolia L.) possesses many nutritional, pharmaceutical and ecological benefits. Morphological and biochemical evaluations of wild oleaster genotypes are pivotal for its conservation, domestication, and breeding programs. In this research, 32 morphological and biochemical traits of oleaster genotypes collected from Iran were evaluated. These genotypes represented a great variety in terms of the evaluated traits. The highest coefficients of variation were noticed on leaf weight (131.96%), fruit flesh weight (54.6%), fruit skin weight (46.92%), fruit flavonoid (42.58%), and fruit weight (42.09%), respectively. Fruit weight varied from 0.26 to 2.84 g. Most of the fruits (41.3%) were red, and most of them (69.7%) had an astringent-sweet taste. The highest mean fruit weight (2.3 g), phenol content (43.06 mg GA/g FW), flavonoid content (8.14 mg CA/g FW), and total soluble solids (26.6°Bx) were for Kuleh sareh, Sarab qamish, Sheykh Vajim and Mamukh genotypes, respectively. Significant positive and negative correlations were observed between the measured traits. Principle component analysis (PCA) grouped the traits into 11 components which accounted for 73.8% of the total variance between genotypes. The weight, width, flesh weight, length, seed weight, seed length, and skin weight of the fruit exhibited the highest factor coefficients in PC1 and were therefore considered as the most influential traits responsible for the segregation of oleaster genotypes. Cluster analysis grouped the genotypes into three main clusters, although the genetic distances of the genotypes were not in accordance with their geographical distances. Based on the breeding aims, the superior genotypes can be used in future programs.