Euphorbia resinifera is a melliferous, medicinal, and endemic plant to Morocco. Nevertheless, its ecological and genetic diversity still unknown. The objective of this study is to analyze the diversity and genetic structure of Moroccan wild populations of E. resinifera using ISSR markers. Twelve natural populations collected from its geographical range in Morocco were analyzed using 14 ISSR primers. A total of 125 bands were obtained, with polymorphism of 74.81%. The polymorphic information content (PIC), resolving power (Rp), Shannon’s information index (I), and total genetic diversity (Ht) were 0.33, 2.8, 0.35, and 0.21, respectively. The analysis of molecular variance showed that 75.56% of the total variability is present within populations and that 24.44% exists among populations. Also, the analysis showed a very low genetic differentiation between groups of mountain range type (FCT = 0.066), mountain versant type groups (FCT = −0.024), and altitude groups (FCT = −0.022). Moreover, the geographical distances between populations are correlated with their corresponding genetic distances according to the Mantel test (r = 0.507; P < 0.0001). These results suggest that the population structuring follows a model of isolation by geographical distance. Indeed, the genetic structuring of populations into two groups obtained from PCoA and structure analysis revealed a dependence on the geographical origin of the populations. By contrast, the genetic distances are not correlated with the altitude.

The Euphorbia resinifera is melliferous and medicinal plant and one of the endemic species of Moroccan Atlas Mountains. It is very well known for its honey of high nutritional and therapeutic quality. The objective of our study is to characterize and evaluate the phenotypic variation of this spontaneous species. Seventeen qualitative and quantitative morphological characters related to the bush, stem, spine, flower, and fruit of the plant were used to assess the morphological variability of twelve natural populations collected from its geographical range in Morocco. The results of the analysis of variance showed significant differences between the studied populations for the most examined traits reflecting the existence of a high phenotypic variability within this species. The principal component analysis showed that E. resinifera populations were clustered in three distinct groups not related to mountain range type. The results highlight a high phenotypic diversity within studied populations of this species in Morocco. This work aims to study the phenotypic variability of E. resinifera to delineate conservation strategies and also to establish forms of rational economic exploitation.