Morphological diversity of argan (Argania spinosa (L.) skeels) populations in Morocco
2004
Fouzia Bani-Aameur
Argan (Argania spinosa (L.) Skeels) populations, a Sapotaceae tree endemic to Morocco, were surveyed for variation of four morphological characters with three to six phenotypic classes. Twenty-five sampling sites were dispersed within four major ecosystems of argan main distribution area south-west of Morocco (5: Haha + Ida Ou Tanane, 6: Souss plain, 13: Center and west High Atlas mountain and 17: Anti Atlas mountain). Variation was monitored using the Shannon-Weaver diversity index (H'). Ecosystem 5 (sub humid to semiarid) was highly significantly less diverse than the three ecosystems 6 (semiarid), 13 (semiarid) or 17 (semiarid to arid). Characters showed a similar level of diversity except within eco system 5 where fruit and stone shapes had lower diversity indices than leaf shape or branching angle. Although populations were highly polymorphic for all characters, polymorphism was low in some populations for fruit and stone shapes, whereas it was high for leaf shape and branching angle in most populations. Indeed, differences between site populations means within the four ecosystems were not significant, their mean diversity index interval being located between 0.76 and 0.48 as compared to global Morocco index (0.64). As it is, this study suggests that, although there is no difference between sites, future conservation plans may have to privilege large numbers of sampling sites within all ecosystems as a precaution not to miss the character diversity.
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