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 thre...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.展开更多
文摘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.
