Assessment of Genetic Diversity of Argania spinosa L. Growing in Arid and Semi-arid Areas of Morocco as Revealed by Inter-Simple Sequence Repeats

Abstract

Argania spinosa L. (Sapotaceae family), endemic to Morocco, is a multipurpose tree with an important ecological and socio-economical interest. Nevertheless, the sustainability of the agro-forestry system is now threatened by overgrazing and over-exploitation leading to an alarming decline in the number of trees. In the present study, inter-simple sequence repeats (ISSR) markers were used to evaluate the genetic variation and to assess the genetic diversity distribution within and among 17 argan populations growing naturally under semi-arid and arid climate. Thus, a total of seven primers generated 260 well-defined bands, with an average of 37.14 bands per primer. Studied populations showed a relatively high level of genetic diversity at species level and low level of genetic diversity at population level. The percentage of polymorphic bands, Nei's gene diversity and Shannon's information index at population and species level were 30.15%, 0.164, 0.217 and 98.8%, 0.172, 0.293, respectively. A relative low level of genetic differentiation (Gst = 0.39) was in agreement with the results obtained from the analysis of molecular variance (AMOVA). Estimated gene flow was Nm = 0.781 among populations. Mantel test revealed a non-significant correlation between genetic and geographic distance (r = 0.065, P < 0.05), suggesting that the geographic distribution is not the major factor that shaped the present population genetic structure. The results can help preserve A. spinosa L. tree as an endangered species, however, refining these finding using co-dominant markers is recommended in order to establish conservation strategies.

Agro-Fruit-Forest Systems Based on Argan Tree in Morocco: A Review of Recent Results

“…The characterization of the genetic variability was evaluated as well through molecular approaches, confirming the important genetic diversity among the argan population. Different types of DNA markers were successfully applied such as RAPD Markers (Majourhat et al, 2008), AFLP markers (Pakhrou et al, 2016), SSR markers (Majourhat et al, 2008;El Bahloul et al, 2014;Chakhchar et al, 2017a), ISSR markers (Ait Aabd et al, 2015;Mouhaddab et al, 2015Mouhaddab et al, , 2016aYatrib et al, 2015;Pakhrou et al, 2017), and IRAP (Pakhrou et al, 2017). The results of these studies show with consistency that argan genetic diversity is high.…”

“…The argan species display a wide genetic diversity, which is evident even within the same locality and under similar ecogeographical conditions. This diversity provides a broad genetic basis for domestication and breeding programs (Mouhaddab et al, 2015(Mouhaddab et al, , 2016b(Mouhaddab et al, , 2017Yatrib et al, 2015;Pakhrou et al, 2016;Chakhchar et al, 2017a). The reproductive mode of A. spinosa, which is essentially allogamic, may explain the origin of such diversity.…”

MULTIPLE SPATIAL CHANGES IN THE ARGAN ECOSYSTEM- (Argania spinosa (L.) Skeels) - CASE STUDY (MOROCCO)

“…Among other impacts, it was an urgent need to measure and analyse it, in order to design action to reverse the process (Laaribya et al, 2021). The sustainability of the Argan agro-forestry system is now threatened by overgrazing and over-exploitation leading to an alarming decline in the number of trees (Yatrib et al, 2015).…”