Study of genetic diversity and differentiation of argan tree population (Argania spinosa L.) using AFLP markers

Abstract

The argan tree (Argania spinosa L. Skeels, Sapotaceae) is a genetic resource endemic in Morocco. Genetic diversity within and among 13 populations (130 genotypes) of argan tree was studied using AFLP markers. Having checked twenty combinations of labeled primers for regular genomes (500-6000 Mb) (EcoRI+3/ MseI+3 selective bases) and for small genome (50-500 Mb) (EcoRI+2/MseI+3 selective bases), we selected four combinations specific for regular genome able to produce a relatively high polymorphism and a low error rate (0.12 %). A total of 477 unambiguous peaks were amplified ranging from 70 to 500 bp. The average polymorphism information content (PICAVG) value ranged from 0.19 to 0.23. Marker index (MI) and resolving power (RP) varied from 21.23 to 28.82 and 27.63 to 44.92, respectively. Analysis of molecular variance (AMOVA) showed that 19 % of the genetic variation was partitioned among populations and 81 % of the genetic variation was within populations. This was confirmed by the coefficient of gene differentiation between populations (Gst=0.22), and gene flow was estimated to 1.709. The STRUCTURE analysis, principal coordinate analysis (PCoA) and Unweighyhed Pair Group Method with Arithmetic Mean (UPGMA) revealed that populations of A. spinosa were clustered into three genetic groups. The present results can be explored in the design of in situ and ex situ conservation and management programs.