Diversité allozymique de peuplements de cyprès naturels et introduits au Maroc: Conséquences pour la gestion des ressources

Abstract

For the purpose of managing Cupressus atlantica natural genetic resources in Morocco, diversity among 9 provenances from 3 cypress species (Cupressus atlantica and 2 introduced species: C. sempervirens and C. arizonica) was studied using seven enzymatic systems. Mean allele number per locus (A) ranged from 2.0 in C. atlantica and C. arizonica to 1.7 in C. sempervirens. Genetic diversity was high (He = 0.29 in C. atlantica; 0.27 in C. sempervirens and 0.33 in C. arizonica) but heterozygote deficiencies were observed. C. atlantica provenances exhibited a low differentiation (G ST = 0.013). The high interspecific differentiation (GST = 0.279) was due to the distance between the 2 Mediterranean cypresses (C. atlantica and C. sempervirens) and the Arizonica cypress. Two enzymatic systems (GOT et SOD) strictly differentiated these 2 origins and could be used for introgression monitoring. Advice for preserving and using C. atlantica genetic resources and for reducing the degradation of these natural stands are proposed.