In vitro propagation of the relict Laperrine's olive (Olea europaea L. subsp. laperrinei)

Olea europaea L. subsp. laperrinei (Oleaceae) is an endemic taxon of the mountainous regions of central Sahara, consisting of currently fragmented and small relict populations. The tree can propagate vegetatively or by seed, but no recent natural regeneration was observed in the Algerian massive populations, some of which are considered threatened with extinction. Sterile triploid individuals were also identified in some populations showing increasing vigour. As a result of its long persistence and despite its rarity, the Laperrine's olive is an iconic component of Saharan mountain ecosystems. The aim of this study is to develop an efficient micropropagation protocol for both diploid and triploid Laperrine's olive to safeguard and preserve this genetic resource. Best shoot propagation was obtained on a modified Murashige and Skoog medium supplemented with 9.2 µM zeatin. Best rooting rate of regenerated shoots was achieved on the same culture medium supplemented with 4.8 µM indole-3-butyric acid. In absence of morphological changes of in vitro regenerated plants acclimatized to the greenhouse, genetic conformity was assessed by simple sequence repeat screening. Our results suggest that in vitro propagation could be a useful tool for conservation of both diploid and triploid threatened Laperrine's olive.