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Crop wild relatives (CWR) are wild species that are more or less genetically related to crops that can be used to introgress useful genes for improvement of productivity, resistance to biotic and abiotic stresses and quality of cultivated crops. They are important in crop improvement to achieve food security for an increasing population and to overcome the challenges caused by climate change and the new virulence of major diseases and pests. These genetic resources are increasingly threatened in their natural habitats through over-exploitation and land reclamation and degradation. Therefore, their efficient and effective conservation would be taxonomically and genetically valuable and will contribute to maintaining and promoting the sustainability of crop diversity, facilitating agricultural production and supporting the increasing demand for food, feed and natural resources. A checklist of 5780 Crop Wild Relatives (CWR) taxa from North Africa was obtained using the CWR Catalogue for Europe and the Mediterranean (PGR Forum). Of which consists 76% of the flora of North Africa. The checklist contains 5588 (~97%) native taxa and 192 introduced. Families with higher taxa richness are Fabaceae, Asteraceae, and Poaceae. These three families constitute more than 33% of the total taxa included in the checklist. About 9% (502) CWR taxa identified as a priority for conservation in North Africa using four criteria, the economic value of the crop, the relatedness degree of wild relatives to their crop, threat status using IUCN red list assessment, and finally the centre of origin and/or diversity of the crop. Of these, 112 taxa were assigned high, 268 medium and 122 low priorities for effective conservation. Those assessed as threatened using IUCN Red list and national assessment represent approximately 2% (119 taxa) of the CWR in the region. However, 21 taxa are assessed as critically endangered (CR), 53 as endangered (EN), and 45 as vulnerable (VU). Wild relatives of some globally important crops are present, with those related to wheat (Triticum aestivum L. and T. durum L.) and barley (Hordeum vulgareL.) among the highest priority crops for the North Africa region. Amongst CWR assessed as threatened, only 8 (6.7%) CWR are related to food crops, Avena agadiriana B.R. Baum. et G. Fedak (VU), A. atlantica B.R. Baum et G. Fedak (VU), A. murphyi Ladiz. (EN), Beta macrocarpa Guss. (EN), Olea europaea subsp. maroccana Guss. (VU), Rorippa hayanicaMaire (VU) and Aegilops bicornis (Forssk.) Jaub. et Spach (VU). The wild relative of Safflower Carthamus glaucus M. Bieb is restricted to Egypt and Libya and assessed as rare in Egypt. The information available about the conservation and threat status of CWR in North Africa still lags behind, and more investigations are required.

Amplified fragment length polymorphism (AFLP) analysis was used to study the genetic variation within and among populations of genus Olea. A group of genotypes, all of them cultivated varieties of a single species, Olea europaea, was compared with wild olives and with a group of individuals belonging to different Olea species. Five primer combinations were used which produced about 290 polymorphic bands. The data obtained were elaborated with the Nei's genetic similarity coefficient, applying different clustering methods and the Principal Coordinate Analysis. Cultivars, wild olives and North-West African species formed groups clustering together at a similarity level of 0.56, while the Olea species from East Africa and Asia grouped separately. Species from the Indian Ocean and Australia showed the highest diversity. We hypothesize that cultivars and wild plants are different forms of the same O. europaea species. The Olea from East Africa and Asia may be assigned to a different species, while the role of O. laperrini as well as that of O. maroccana as an intermediary form is confirmed.

We assessed the genetic differentiation of the Mediterranean olive from its wild relatives found in different geographic areas (Mediterranean, Asia, Africa) using eighty RAPDs revealed with eight primers. Variance analysis (AMOVA) enabled us to estimate the overall genetic differentiation parameters between wild populations. Oleasters from the Near East and Turkey were discriminated from the other Mediterranean populations. Olea laperrinei, O. maroccana and O. cerasiformis were the taxa the most related to the Mediterranean olive. In contrast, O. africana was shown to be the most genetically distant taxa from the Mediterranean olive. However, we characterised hybrid trees between these two taxa. Significant trends between genetic and geographic distances were met within the subspecies cuspidata and within the Mediterranean olive. A genetic diversity gradient was observed in both subspecies europaea and cuspidata. These results are in agreement with a mechanism of differentiation by distance in the O. europaea complex, but another non-exclusive mechanism could also be gene flow between differentiated taxa. Furthermore, we characterised the discriminating power of each RAPD to recognise the different taxa using intraclass correlation coefficients. Lastly, IGS-RFLPs enabled us to assess rDNA polymorphisms on a sub-sample of individuals. On the basis of these data, a low interspecifc differentiation was found. This suggests a recent genetic divergence between the different taxa of the O. europaea complex or the occurrence of gene flow during favourable periods or because human displacements. All the olive cultivars were genetically related to the oleaster populations supporting that Mediterranean is the olive domestication area.

Polymorphism in the lengths of restriction fragments of the whole cpDNA molecule were studied in 15 taxa (species or subspecies) of the genus Olea. From restriction analysis using nine endonucleases, 28 site mutations and five length polymorphisms were identified, corresponding to 12 distinct chlorotypes. From a phenetic analysis based on a Nei's dissimilarity matrix and a Dollo parsimony cladistic analysis using, as an outgroup, a species of the genus Phillyrea close to Olea, the ten taxa of section Olea were distinguished clearly from the five taxa of section Ligustroides which appear to posses more ancestral cpDNA variants. Within the section Ligustroides, the tropical species from central-western Africa, Olea hochtetteri, showed a chlorotype which differed substantially from those of the other four Olea taxa growing in southern Africa, supporting a previous assessment according to which O. hochtetteri may have been subjected to a long period of geographical isolation from the other Olea taxa. Within the Olea section, three phyla were identified corresponding to South and East Africa taxa, Asiatic taxa, and a group including Saharan, Macaronesian and Mediteranean taxa, respectively. On the basis of cpDNA variation, the closest Olea taxa to the single Mediterranean species, Olea europaea, represented by its very predominant chlorotype, observed in both wild and cultivated olive, were found to be Olea laperrinei (from the Sahara), Olea maroccana (from Maroccan High Atlas) and Olea cerasiformis (from Macaronesia). These three taxa, which all share the same chlorotype, may have a common maternal origin.[PUBLICATION ABSTRACT]

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. laperrineisubsp. 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.[PUBLICATION ABSTRACT]