Chloroplast-DNA variation in the wild and cultivated olives (Olea europaea L.) of Morocco

Polymorphism in the lengths of restriction fragments of the whole cpDNA molecule was studied in cultivated and wild olive growing throughout Morocco. The main Moroccan varieties and old trees cultivated locally (66 individuals), wild olive (45 individuals) and 5 individuals of the taxon, O. laperrinei subsp. maroccana endemic to the western part of the High Atlas, were scored for 10 restriction enzymes. A total of 470 restriction fragments were obtained of which 18 were variable. Four chlorotypes were identified. Chlorotype (I), predominant in wild and cultivated olive of the whole Mediterranean Basin, was observed in all the cultivated trees and in 74% of the wild trees (oleasters) analysed from Morocco, confirming that cultivated and wild olive material are closely related maternally. Chlorotypes II and III, each characterised by a length mutation, were observed exclusively in Moroccan wild types, suggesting that these did not originate exclusively in cultivated varieties, as reported previously by several authors. As compared to the predominant chlorotype I, Chlorotype IV, characterised by a site mutation, was present exclusively in the maroccana individuals, confirming the originality of this taxon.