Environmental and genetic interactions underlying the morphological and genetic variability of the red juniper (Juniperus turbinata Guss.) in northeastern Morocco: implications for conservation

Plant species often show morphological variations in response to their environments. In this study, we examined the trees, cones, seeds and leaves of three populations of Juniperus turbinata in north-eastern Morocco, located in littoral, semi-continental and continental zones, to evaluate how local conditions influence morphological characters. Additionally, a genetic study using Simple Sequence Repeat (SSR) markers was conducted to assess the genetic diversity and structure within these populations, aiming to determine the genetic contributions to observed morphological differences. The results showed significant morphological variation across zones. Cones from the littoral population were larger and rounder, while those of the semi-continental and continental populations were more elongated and robust. Seeds and leaves characters also varied in patterns linked with elevation and aridity. Genetic analysis revealed moderate differentiation among populations, with higher genetic diversity in the continental site, as confirmed by several calculated indices such as the number of effective and private alleles, Shannon’s information index, and observed and expected heterozygosities. Interestingly, the population structure profile identified two distinct genetic pools, with littoral and continental populations clustering closely together. This limited genetic differentiation likely due to gene flow or shared ancestry, suggests the formation of a single genetic group despite geographical separation. The results of this study show that the local environmental factors are the primary drivers of morphological variation, particularly in cones and seeds, while also highlighting a notable genetic component. These findings data are essential for defining conservation strategies adapted to local populations of J. turbinata in the context of climate change.