The length, number, and endodermis area of needles discriminate two genetically distinct populations of Cedrus atlantica Manetti in the Moroccan Middle Atlas

The variation in some adaptive characters of cedar needles was studied in two different regions of the Moroccan Middle Atlas that have different local environmental conditions and levels of genetic diversity. The two populations are localized in the Azrou and Ifrane regions. Tukey’s tests showed that the needle/brachyblast number (Nn/R), length (Nl), and needle width (Nw) showed the greatest variation. In addition, all anatomical characters studied showed a significant correlation with Nw, whereas only the area of the vascular bundles (AVb) was related to Nl. Discriminant analysis revealed that Nn/R, Nl, and the area of the central cylinder (ACc) are high-discriminating characters among populations of Azrou and Ifrane and confirms their isolation. These adaptations of the morphological and anatomical traits of the Atlas cedar needles of the Azrou and Ifrane regions are discussed in relation to the local environmental conditions and have been found to be in harmony with their genetic distinctiveness revealed previously.