Genetic Variability of Argan Tree and Preselection of the Candidate Plus Trees

Argan tree productivity shows a wide disparity in space and time, while the degraded forest areas show low growth and unproductive shrubs. Moreover, even if reforestation, currently led by various local actors (Waters and Forests, Agency of Social Development, Cooperatives and Associations of development) experienced a technical improvement, the plants used do not meet any selection criteria. Generally, unknown origin seedlings are used in reforestation and good seedlings are not reproduced. In this context, this study investigates through a choice of pilot sites the characterization in-situ of populations and/or argan trees with two selection criteria related to fruit: facility of crushing and oil content. For this purpose, and with the support of local population, the identification of performance trees, prospection and collection of fruits were realized in various sites representing five principal provinces of argan trees area (Essaouira; Taroudante; Agadir Ida Outanane; Chtouka-Ait Baha and Tiznit). Within each provenance, measurements related to 6750 fruits and the morphometric data were subjected to the analysis of the variance, according to the general linear model, where the genotype factor (mother tree) is hierarchical to provenance factor. This study offers preliminary information for the development of a breeding population and allows us to make a first selection of trees, having a clear superiority relating to the characters related to the production of oil and the facility of crushing seeds. At the present moment there is a genetic base large enough to initiate a breeding program

Patterns of Genetic Diversity and Structure at Fine Scale of an Endangered Moroccan Endemic Tree (Argania spinosa L. Skeels) Based on ISSR Polymorphism

The preservation of the diversity of endangered populations of argan trees, in their natural habitat, is a crucial step toward their conservation. The aim of the present study was to evaluate the genetic diversity of the argan trees in the wild, and to establish a phylogenetic map using DNA fingerprints. The ultimate goal was to develop a core set that would represent the existing diversity in the whole germplasm. In regard to this, 200 samples of Argania spinosa individual trees were collected from 10 different provenances in the region of Essaouira (Morocco). The genetic variation between and within these argan trees was investigated using previously described Inter-Simple Sequence Repeat markers. These markers generated a total of 149 fragments, in which 148 (99.33%) were polymorphic. The samples collected in the 'Ouled Lhaj' provenance showed the lowest diversity (% of polymorphic locus P=48.32%; genetic diversity Nei h=0.153; allelic richness A=1.483), compared to those collected in the 'Mramer' provenance (%P=68.46%; h=0.233; A=1.685). Also, the results showed a high level of genetic differentiation among provenances (AMOVA=44%, Gst=0.40), and a limited gene flow (Nm=0.73) between the provenances. In addition, these data suggested a low correlation between the genetic diversity of the tree and their respective geographical location in relation to the proximity to the littoral. Finally, a core collection of 13 genotypes that represent the essential of the detected diversity was established. The distribution pattern of this genetic diversity provides an important baseline data for the conservation strategies of argan tree species in the wild

The use of plants in the traditional treatment of diabetes patients: survey in southern Morocco

This study was conducted in public healthcare establishments in Guelmim city in south of Morocco to report medicinal plants used in folk medicine to treat diabetes. Three hundred sixty-two informants were interviewed through semi structured interviews. The inventory includes scientific, popular and common names of the plants, used parts and method of preparation. The survey shows that 24.6% of the patients use these plants. Twenty-seven medicinal plants belonging to seventeen families were inventoried and three species were cited for the first time in the treatment of diabetes in Morocco. Olea europea L., Artemisia herba-alba Asso and Trigonella foenum-graecum L. are the most plant species used to treat diabetes, and the two most cited families are Lamiaceae (5 species) and Apiaceae (4 species). Leaves represented the most utilized part of plants and decoction was the most cited mode of preparation of drugs. The present study highlights the wide variety of herbal remedies used to treat diabetes and the frequency of this use in diabetic patients

Univariate and Multivariate Analysis of Agronomical Traits of Preselected Argan Trees

A collection of thirty argan trees (Argania spinosa (L.) Skeels), representing the Aoulouz provenance in southwest of Morocco were used to study genetic variability and selection for three years. In this study, the genetic diversity of thirty genotypes (tree mothers) of argan (Argania spinosa) collected from Aoulouz was evaluated using agro-morphological characters. The main objective of the study was to assess and describe with multivariate analysis the genetic diversity in order to select good candidate trees for a future breeding program. The results obtained showed a large variation for all the traits examined. Analysis of variance using general linear model provided a significant variation between genotypes. Furthermore, genotypic and phenotypic variances for quantitative traits, particularly for seed length, seed width, almond length and oil content were higher. Phenotypic coefficient of variation was higher than genotypic coefficient of variation for all the characters. High heritability was recorded for oil content (97.90%), seed width (72.68%) and seed length (57.55%) respectively, indicating the additive gene action. In addition, a three dimensional plot based on principal coordinate analysis method was used to evaluate the performance genotypes as to the production of oil for three years. The genotypes ‘Ao-12R’, ‘Ao-7R’, ‘Ao-4R’, ‘Ao-4V’, ‘Ao-11R’, ‘Ao-8V’ and ‘Ao-7V’ were found to be the best for high oil content. Identification and selection with superior agronomic traits may be an effective method for genetic improvement of argan trees, and a first step for further breeding studies

Univariate and Multivariate Analysis of Agronomical Traits of Preselected Argan Trees

A collection of thirty argan trees (Argania spinosa (L.) Skeels), representing the Aoulouz provenance in southwest of Morocco were used to study genetic variability and selection for three years. In this study, the genetic diversity of thirty genotypes (tree mothers) of argan (Argania spinosa) collected from Aoulouz was evaluated using agro-morphological characters. The main objective of the study was to assess and describe with multivariate analysis the genetic diversity in order to select good candidate trees for a future breeding program. The results obtained showed a large variation for all the traits examined. Analysis of variance using general linear model provided a significant variation between genotypes. Furthermore, genotypic and phenotypic variances for quantitative traits, particularly for seed length, seed width, almond length and oil content were higher. Phenotypic coefficient of variation was higher than genotypic coefficient of variation for all the characters. High heritability was recorded for oil content (97.90%), seed width (72.68%) and seed length (57.55%) respectively, indicating the additive gene action. In addition, a three dimensional plot based on principal coordinate analysis method was used to evaluate the performance genotypes as to the production of oil for three years. The genotypes ‘Ao-12R’, ‘Ao-7R’, ‘Ao-4R’, ‘Ao-4V’, ‘Ao-11R’, ‘Ao-8V’ and ‘Ao-7V’ were found to be the best for high oil content. Identification and selection with superior agronomic traits may be an effective method for genetic improvement of argan trees, and a first step for further breeding studies

Phylogeography at the crossroad: Pleistocene range expansion throughout the Mediterranean and back-colonization from the Canary Islands in the legume Bituminaria bituminosa

Aim: Species with widespread distributions offer excellent opportunities for investigating recent biogeographical patterns across broad scales. Here, we tested the hypothesis that, due to its intermediate geographical location, NW Africa is pivotal in explaining the phylogeographical patterns of taxa with Mediterranean–Macaronesian distributions using a legume species with short generation times. Location: Mediterranean, with a focus on NW Africa and the Canary Islands. Taxon: Pitch trefoil (Bituminaria bituminosa). Methods: We generated genetic data and performed phylogeographical and demographic analyses at two geographical scales: Mediterranean Basin (MB), using plastid sequences (115 individuals), and Macaronesia, using plastid sequences (182 individuals) and 10 nuclear microsatellite loci (220 individuals). We also performed a literature survey focusing on phylogeographical studies of other circum-Mediterranean taxa. Results: Northwest Africa was identified as a centre of genetic diversity (19 out of 38 haplotypes) and demographic expansion of B. bituminosa in the MB during the Pleistocene. Our literature review revealed two main phylogeographical patterns in widespread species: pre-Mediterranean evergreen sclerophylls versus Pleistocene facultative-deciduous (including Bituminaria) taxa, but on average, both functional groups show a similar, large genetic diversity (~40% of haplotypes) in NW Africa. At the Macaronesian scale, we found that Canarian Bituminaria is composed of two genetic sublineages that coexist and hybridize on the central islands and in the mainland Macaronesian enclave (Anti-Atlas region). Demographic analyses rejected the progression rule as the model of island colonization but strongly suggested that AntiAtlas populations are the result of back-colonization from the easternmost islands before the Last Glacial Maximum (LGM). Conclusions: Bituminaria displays a pattern of Quaternary eastward expansion in the MB that appears to be paralleled by several members of its functional plant group. Thus, our study reveals a previously undescribed dual role of NW Africa in plant biogeography, acting both as a source of species expansion to the rest of the MB and a LGM refugium of plant populations with a Macaronesian island origin

Analyse de la plasticité phénotypique de l'arganier (Arganiaspinosa L.) sous différentes conditions géographiques et identification des descripteurs morphologiques déterminants sa diversité génétique

A large sampling of argan trees (Argania spinosa L.) has been established in the five provinces of argan ecosystems. The main objective of the study was to assess and describe the genetic variation using univariate and multivariate analyses and to describe their productivity under different geographical conditions. 150 wild trees were sampled across various sites representing the principal natural range of argan trees area: (Had Dra/Essaouira, Aoulouz /Taroudant, Alma/Agadir-Ida Outanane, Biougra/Chtouka-Ait Baha and Lakhsas/Tiznit). The qualitative and quantitative traits related to tree, fruit, seed and almond were used during three years in the fields (n = 150) for the tree and the laboratory for the fruits (n = 37800) to evaluate the genetic variation within and among provenances. The results obtained from the analysis of the variance, according to the general linear model (P ≤ 0.001), showed a large variation for all the traits. Furthermore, the Shannon-Weaver diversity index (H’) varied for different qualitative characters. The inter- and intra-provenance distribution of this variance was investigated. The results showed that for the productivity under different geographical conditions, 30 kg of fruit gives 17 kg of seed, 2 kg of almond, 15 kg of hull and 1/2 L of oil. The genetic variation is mainly present among and within sites studied. Based on the hierarchical cluster analysis, respectively, two clusters were obtained. The first cluster is composed of the two provenances: Had Dra and Biougra, with the highest means values of traits. The second cluster presented by the Alma, Aoulouz and Lakhsas, provenances with lowest means values of traits studied. In general, great variability was noted and not associated with eco-geographical origin. So, the high degree of variation among genotypes could be useful for selection and breeding programs.Un grand échantillonnage d'arganiers (Arganiaspinosa L.) a été établi dans les cinq provinces d’écosystèmes d'arganiers. L'objectif principal de l'étude était d'évaluer et de décrire la variation génétique des arganiers à l'aide d'analyses uni-variées et multi-variées et de décrire leur productivité dans différentes conditions géographiques. 150 arbres sauvages ont été échantillonnés dans divers sites représentant la principale aire de répartition naturelle d’arganier : (Had Dra / Essaouira, Aoulouz / Taroudant, Alma / Agadir-Ida Outanane, Biougra / Chtouka-Ait Baha et Lakhsas / Tiznit). Les traits qualitatifs et quantitatifs liés à l'arbre, au fruit, à la graine et à l'amandier ont été utilisés pendant trois ans dans le terrain pour l'arbre (n = 150) et dans laboratoire pour les fruits (n = 37800), pour évaluer la variation génétique au sein et entre les provenances. Les résultats obtenus par l'analyse de la variance, selon le modèle linéaire général (P ≤ 0,001), ont montré une grande variation pour tous les traits. De plus, l’indice de diversité de Shannon-Weaver (H’) varie pour différents caractères qualitatifs. La distribution inter et intra-provenances de cette variance a été étudiée. Les résultats montrent que pour la productivité sous différentes conditions géographiques, 30 kg de fruits donnent 17 kg de graines, 2 kg d'amandes, 15 kg de coque et 1/2 L d'huile. La variation génétique est principalement présente entre et au sein des sites étudiés. Sur la base de l'analyse hiérarchique, respectivement, deux groupes ont été obtenues. Le premier groupe est composé de  deux provenances : Had Dra et Biougra, avec les valeurs moyennes des traits les plus élevées. Le deuxième groupe est présenté par les provenances Alma, Aoulouz et Lakhsas. En général, une grande variabilité a été notée et non associée à l'origine éco-géographique. Ainsi, le degré élevé de variation entre les génotypes pourrait être utile pour les programmes de sélection et d’amélioration

Saline Water Irrigation Effect on Oil Yield and Quality of Argan Trees Domesticated in Laâyoune, Morocco

Salinity is one of the major severe constraints that limit crop productivity in 40% of the land surface, notably in the Mediterranean region. In this study, we worked in an argan orchard located in Laâyoune, Morocco. The orchard is characterized by a saline soil and trees that are irrigated with highly saline water. The study aimed to evaluate the effect of irrigation with saline water on oil yield, total phenolic content, flavonoid content, antioxidant activity, and fatty acid composition. The results show that saline water irrigation has a no significant effect on oil yield and most oil quality parameters, yet has a highly significant effect on total polyphenols, flavonoid content as well as two saturated acids (C16:0 and C20:0)