Verifying the reliability of hybrid issued from the cross “Picholine marocaine clones X Picholine du Languedoc”

In order to verify the reliability of hybrid population issued from crossing between 3 clones of "Picholine marocaine" cultivar and the "Picholine du Languedoc" cultivar, the descendants and their parents wereanalysed using 35 microsatellite loci. No offspring resulted from self crossing of "Picholine marocaine" cultivar and 218 descendants among 220 analysed are legitimate. This study showed clearly a segregating population and may be used as a genetic material for linkage map construction and for phenotyping resistance traits related to Spilocaea oleagina disease

Effects of a Composite Endomycorrhizal Inoculum on Olive Cuttings under the Greenhouse Conditions

This study was carried out in a nursery to evaluate the impact of mycorrhizal fungi on the cutting's root growth, and root colonization of a Moroccan olive variety ‘Picholine Marocaine' under greenhouse conditions during 2 years of cultivation. The results revealed that the inoculation with a composite inoculum of arbuscular mycorrhizal fungi (AMF) stimulated an early root formation and high development of vegetative shoots in inoculated cuttings respectively, 35 days (50 days in the control plots) and 40 days (60 days in the control plots) after their culture. The progressive establishment of mycorrhizal symbiosis in the roots of the inoculated plants showed that the root and vegetative masses were respectively 24 g and 19.5 g two years after inoculation. The average height and the leave's number of the inoculated plants relative to the control were respectively s 42/ 12 cm and 145/12. The newly formed roots were mycorrhizal and present different structures characteristic of AMF: arbuscules, vesicles, hyphae and spores, whose frequency and intensity reached 90% and 75% two years after cuttings cultivation. The arbuscular and vesicular contents and the number of spores were 67%, 96% and 212 spores/ 100 g of soil respectively. The fourteen species of mycorrhizal fungi isolated from the rhizosphere belong to 4 genera (Glomus, Acaulospora, Gigaspora, and Scutellospora) and three families (Glomaceae, Acaulosporaceae and Gigasporacea).The Glomus genus was the most dominant (65%) followed by the Gigaspora genus (22%). Glomus intraradices, Gigaspora sp.2, Glomus versiformes are the most abundant species, their frequency of occurrence are respectively 30%, 21% and 16%

Substantial genetic diversity in cultivated Moroccan olive despite a single major cultivar: a paradoxical situation evidenced by the use of SSR loci

UMR DAP, équipe AFEFInternational audienceTo assess the genetic diversity in Moroccan cultivated olive, Olea europaea L. subsp. europaea, we performed molecular analysis of olive trees sampled in four geographic zones representing all areas of traditional olive culture. The analysis of 215 trees using 15 simple sequence repeat (SSR) loci revealed 105 alleles distributed among 60 SSR profiles. The analysis of chloroplast deoxyribonucleic acid polymorphism for these 60 olive genotypes allowed to identify four chlorotypes: 42 CE1, one CE2, nine COM1and eight CCK. Among the 60 SSR profiles, 52 corresponded to cultivated olive trees for which neither denomination nor characterisation is available. These local olive genotypes displayed a spatial genetic structuring over the four Moroccan geographic zones (northwest, north centre, Atlas and southwest), as pairwise Fst values ranged from 0.0394 to 0.1383 and varied according to geographic distance. As single alleles detected in local olive were also observed in Moroccan oleaster populations, results suggest that plant material was mainly selected from indigenous populations. The assumption that Picholine marocaine cultivar is a multi-clonal cultivar was not supported by our data because we found a single genotype for 112 olive trees representing 31 to 93% of the olives sampled locally in the 14 different areas. Picholine marocaine and the few other named cultivars do not seem to belong to the same gene pools as the unnamed genotypes cultivated only locally. The situation is paradoxical: a substantial genetic diversity in Moroccan olive germplasm, probably resulting from much local domestication, but a single cultivar is predominan

L’oléiculture au Maroc de la préhistoire à nos jours : pratiques, diversité, adaptation, usages, commerce et politiques

International audienceCe numéro propose une relecture de la place de l’oléiculture dans l’histoire de l’Ouest méditerranéen et plus particulièrement le Maroc. L’olivier y est considéré comme un modèle des relations sociales et environnementales : la distribution de la diversité génétique, les flux de gènes entre oliviers et oléastres, ou l’équilibre entre les variétés locales et les variétés étrangères sont liés aux stratégies de conservation, de sélection, d’amélioration et aux stratégies de développement et de valorisation oléicoles. La question de l’impact de la sélection variétale et de la dynamique évolutive de l’olivier constitue un axe commun aux chercheurs engagés dans différentes disciplines (écologie, biologie, génétique, ethnobiologie, archéologie, archéobotanique, histoire, agronomie, socio-économie, économie politique internationale). Leurs travaux mettent en perspective différents facteurs déterminant les dynamiques variétales, environnementales et sociales. Au début, les contributions apportent de nouveaux éléments sur la manière d’analyser et d’interpréter la diversité variétale et l’évolution de l’oléiculture depuis la préhistoire à la période contemporaine. Puis les approches de la génétique et de l'histoire interrogent la dominance de la « Picholine marocaine ». L'origine de cette variété, les facteurs historiques de sa diffusion au Maroc, son impact sur les agroécosystèmes traditionnels et sur la conception des programmes de sélection génétique y sont analysés. Afin d’approfondir les dynamiques à l’œuvre dans la diversification variétale de l’olivier, les approches de la génétique, de la socio-économie et de l’ethnobotanique, analysent l’évolution des écosystèmes et des pratiques paysannes. L’angle de l’économie politique internationale et de la socio-économie interroge alors le rôle des opérateurs privés et des organismes publics dans la diffusion variétale, en se focalisant en particulier sur les pépinières et les appellations d’origine oléicoles. Enfin, les dernières contributions présentent de nouvelles approches pour l'étude de l’olivier au Maroc. Des résultats préliminaires sur la plasticité de l’olivier, sur les caractères anatomiques de son bois et sur les données relatives au pollen y sont restitués. L’ensemble de ce travail fournit des éléments de réponse nuancés sur les facteurs déterminant la diffusion variétale et la dynamique de la diversification de l’olivier. Il ouvre de nouvelles pistes de recherche sur les mesures permettant de mieux évaluer les adaptations aux changements environnementaux et sur le rôle des politiques économiques dans la diffusion variétale

Population genetics of Mediterranean and Saharan olives: geographic patterns of differentiation and evidence for early generations of admixture

BACKGROUND & AIMS : The olive (Olea europaea subsp. europaea) was domesticated in the Mediterranean area but its wild relatives are distributed over three continents, from the Mediterranean basin to South Africa and south-western Asia. Recent studies suggested that this crop originated in the Levant while a secondary diversification occurred in most westward areas. A possible contribution of the Saharan subspecies (subsp. laperrinei) has been highlighted, but the data available were too limited to draw definite conclusions. Here, patterns of genetic differentiation in the Mediterranean and Saharan olives are analysed to test for recent admixture between these taxa.[br/] METHODS : Nuclear microsatellite and plastid DNA (ptDNA) data were compiled from previous studies and completed for a sample of 470 cultivars, 390 wild Mediterranean trees and 270 Saharan olives. A network was reconstructed for the ptDNA haplotypes, while a Bayesian clustering method was applied to identify the main gene pools in the data set and then simulate and test for early generations of admixture between Mediterranean and Saharan olives. [br/] KEY RESULTS : Four lineages of ptDNA haplotypes are recognized: three from the Mediterranean basin and one from the Sahara. Only one haplotype, primarily distributed in the Sahara, is shared between laperrinei and europaea. This haplotype is detected once in Dhokar, a cultivar from the Maghreb. Nuclear microsatellites show geographic patterns of genetic differentiation in the Mediterranean olive that reflect the primary origins of cultivars in the Levant, and indicate a high genetic differentiation between europaea and laperrinei. No first-generation hybrid between europaea and laperrinei is detected, but recent, reciprocal admixture between Mediterranean and Saharan subspecies is found in a few accessions, including Dhokar. [br/] CONCLUSIONS : This study reports for the first time admixture between Mediterranean and Saharan olives. Although its contribution remains limited, Laperrines olive has been involved in the diversification of cultivated olives

Diversity of plant-parasitic nematode communities associated with olive nurseries in Morocco : origin and environmental impacts

Plant-parasitic nematodes (PPN) are key impediments to efficient global crop production and impair the quality of susceptible plants in nurseries as well. In this context, nematode communities were determined in 305 solid substrate samples collected from 25 olive (Olea. europaea. subsp. europaea) nurseries in Morocco. Taxonomical and functional diversity as well as the structures of PPN communities were described and then compared between regions, cultivars as well as according to biotic and abiotic factors. A high diversity of PPN was observed, with the detection of 63 species and 26 genera. The most dominant taxa detected were spiral nematodes (Helicotylenchus spp. and Rotylenchus spp.), stunt nematodes (Tylenchorhynchus spp.), grazer nematodes (Tylenchus spp.) and root-knot nematodes (Meloidogyne spp.). Hoplolaimidae nematodes (Helicotylenchus spp. and Rotylenchus spp.) and Tylenchus spp. were better adapted to rainy conditions that prevailed in the northern regions of Morocco. Multiblock analyses demonstrated that functional diversity (cp and trophic groups) was more affected by the environment than taxonomical diversity (total number, species richness, locale diversity and evenness). They also indicated that PPN communities were more impacted by climatic variables (rainfall and minimum temperature) and nursery substrate origins than by soil physic-chemical factors. Nevertheless, a co-inertia analysis showed that N, P and K amendments in olive nurseries enhanced the development of harmful PPN, especially root-knot nematodes

A genetic linkage map of olea europaea L. using a pseudo-test cross- mapping strategy based on SSR, AFLP, ISSR, RAPD and SCAR markers

International audienceA genetic map of olive tree (Olea europaea; 2n = 46) was constructed with a total of 343 markers: 35 SSRs, 272 AFLPs, 35 ISSRs, and RAPD and SCAR scored in 140 F1 progenies from the cross between ‘Picholine marocaine’ ‘PM’ (female parent) and ‘Picholine du Languedoc’‘PL’ (male parent), respectively susceptible and resistant to Spilocaea oleagina. The female map consisted of 100 markers clustered in 24 linkage groups (LG) and covered over 1260.9 cM, while the male map was defined by 90 markers assigned to 22 linkage groups and covered 1183 cM. The consensus map obtained based on 193 markers (26 SSRs, 151 AFLPs, 12 ISSRs, 3 RAPDs, 1 SCAR) and 31 linkage groups covered 2332.8 cM

Plant parasitic nematodes communities associated with olive trees in Morocco

Plant-parasitic nematodes significantly contribute to economic losses in the ten top oliveproducing countries in the world, especially in the Mediterranean basin (Spain, Italy, Greece,Tunisia, and Morocco).Diversity and structures of plant-parasitic nematode communities respondto evolutionary, environmental and anthropogenic forces. Instead of controlling the main pathogenicnematode species as usual, one of the innovative strategies to control plant-parasitic nematodes wouldbe to manage diversity in communities in order to lead them to be less pathogenic. The present studyaims at understanding the contribution of olive domestication and human impacts on the plantparasiticnematode communities by analyzing the diversity of plant-parasitic nematodes in cultivatedolive compared to wild olive in Morocco. Thus, 220 samples were collected in 2012 in several sites withcultivated and feral olive trees (i.e. wild olive resulting from cultivated olive) in the olive production areaslocated all along the Atlas foothills, as well as on wild olive Morphobiometric observations revealeda significant diversity of plant-parasitic nematodes, belonging to 12 families and 28 genera. Our resultsshowed the presence of genera Pratylenchus and Meloidogyne in all sampled systems that are knownharmful taxa for agriculture especially in nurseries. These two genera were more abundant in thecropped systems. Principal component analysis revealed no significant effect of olive systems onthe diversity of PPN in communities but on the PPN community patterns Other factors such asolive genotype, soil physic-chemical characteristics, geo-climatic characteristics, associated plants witholive trees will also be discussed as major factors affecting the plant-parasitic nematode communitypatterns