Traditional agroecosystems as conservatories and incubators of cultivated plant varietal diversity: the case of fig (Ficus carica L.) in Morocco

<p>Abstract</p> <p>Background</p> <p>Traditional agroecosystems are known to host both large crop species diversity and high within crop genetic diversity. In a context of global change, this diversity may be needed to feed the world. Are these agroecosystems museums (i.e. large core collections) or cradles of diversity? We investigated this question for a clonally propagated plant, fig (<it>Ficus carica</it>), within its native range, in Morocco, but as far away as possible from supposed centers of domestication.</p> <p>Results</p> <p>Fig varieties were locally numerous. They were found to be mainly highly local and corresponded to clones propagated vegetatively. Nevertheless these clones were often sufficiently old to have accumulated somatic mutations for selected traits (fig skin color) and at neutral loci (microsatellite markers). Further the pattern of spatial genetic structure was similar to the pattern expected in natural population for a mutation/drift/migration model at equilibrium, with homogeneous levels of local genetic diversity throughout Moroccan traditional agroecosystems.</p> <p>Conclusions</p> <p>We conclude that traditional agroecosystems constitue active incubators of varietal diversity even for clonally propagated crop species, and even when varieties correspond to clones that are often old. As only female fig is cultivated, wild fig and cultivated fig probably constitute a single evolutionary unit within these traditional agroecosystems. Core collections, however useful, are museums and hence cannot serve the same functions as traditional agroecosystems.</p

Age, Growth and Mortality of Atlantic chub mackerel, Scomber colias Gmelin, 1789 in the Mediterranean Waters of Morocco

This work is a study of growth aspects and mortality of the Atlantic chub mackerel, Scomber colia, from the Mediterranean Moroccan coast. A total of 845 specimens were collected from commercial catches in M'diq Bay, whose total length ranged between 16.4 and 35.9 cm. The length-weight relationship was W = 0.0019 TL3.4527 (r = 0.97) for the whole population. The Atlantic chub mackerel displays positive allometric growth. Otolith edge analysis indicated that opaque zones were formed between April and September and translucent ones during the remaining months of the year. The oldest individuals in the sample were 5 years old for both sexes. Von Bertalanffy growth parameters estimated for this species were: L∞ = 37.30 cm, k = 0.26 year-1 and t0 = - 2.19 year. The difference in growth between sexes is not significant. The estimated natural mortality was 0.59 per year

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

Gene flow among wild and domesticated almond species: insights from chloroplast and nuclear markers

Hybridization has played a central role in the evolutionary history of domesticated plants. Notably, several breeding programs relying on gene introgression from the wild compartment have been performed in fruit tree species within the genus Prunus but few studies investigated spontaneous gene flow among wild and domesticated Prunus species. Consequently, a comprehensive understanding of genetic relationships and levels of gene flow between domesticated and wild Prunus species is needed. Combining nuclear and chloroplastic microsatellites, we investigated the gene flow and hybridization among two key almond tree species, the cultivated Prunus dulcis and one of the most widespread wild relative Prunus orientalis in the Fertile Crescent. We detected high genetic diversity levels in both species along with substantial and symmetric gene flow between the domesticated P. dulcis and the wild P. orientalis. These results were discussed in light of the cultivated species diversity, by outlining the frequent spontaneous genetic contributions of wild species to the domesticated compartment. In addition, crop-to-wild gene flow suggests that ad hoc transgene containment strategies would be required if genetically modified cultivars were introduced in the northwestern Mediterranean

Grafting versus seed propagated apricot populations: two main gene pools in Tunisia evidenced by SSR markers and model-based Bayesian clustering

Apricot was introduced into the Mediterranean Basin from China and Asian mountains through the Middle-East and the Central Europe. Traditionally present in Tunisia, we were interested in accessing the origin of apricot species in the country, and in particular in the number and the location of its introductions. A set of 82 representative apricot accessions including 49 grafted cultivars and 33 seed propagated ‘Bargougs’ were genotyped using 24 microsatellite loci revealing a total of 135 alleles. The model-based Bayesian clustering analysis using both Structure and InStruct programs as well as the multivariate method revealed five distinct genetic clusters. The genetic differentiation among clusters showed that cluster 1, with only four cultivars, was the most differentiated from the four remaining genetic clusters, which constituted the largest part of the studied germplasm. According to their geographic origin, the five identified groups (north, centre, south, Gafsa oasis and other oases groups) enclosed a similar variation within group, with a low level of differentiation. Overall results highlighted the distinction of two apricot gene pools in Tunisia related to the different mode of propagation of the cultivars: grafted and seed propagated apricot, which enclosed a narrow genetic basis. Our findings support the assumption that grafting and seed propagated apricots shared the same origin

Microsatellite markers as reliable tools for fig cultivar identification

UMR DAP, équipe AFEF; UMR DIAPC Publication Inra prise en compte dans l'analyse bibliométrique des publications scientifiques mondiales sur les Fruits, les Légumes et la Pomme de terre. Période 2000-2012. http://prodinra.inra.fr/record/256699International audienceAccurate and reliable cultivar identification of crop species is essential to ensure plant material identity for registration and for cultivar protection. In this article, we proposed six simple sequence repeat (SSR) loci as a sufficient tool to characterize fig (Ficus carica L.) germplasm in Morocco maintained in an ex situ collection. A set of 17 microsatellite loci was used to characterize 75 accessions representing eight caprifigs, 51 local accessions, 11 foreign accessions, and five accessions of unknown origin. Eighty-five alleles with a mean number of six alleles per locus were observed in 62 distinct genotypes. Suspected synonyms and homonyms were confirmed, some of which maybe resulted from somatic mutation. Based on genetic criteria, including linkage disequilibrium, discrimination power, and molecular criteria as polymerase chain reaction conditions of loci multiplexing, we proposed a key identification set using six microsatellite markers to discriminate all genotypes present in the ex situ collection. Our selected SSR loci set can be used for larger genetic studies of fig germplasm, and a similar approach can be adopted for other fruit specie

Maturity and spawning of Atlantic chub mackerel

Knowledge of reproductive parameters is necessary to understand the ecology, the population dynamics and to enable rational management of fish of economic interest. This work is a contribution to the study of some aspects of the reproductive biology of the Atlantic mackerel Scomber colias (Gmelin, 1789) in the Mediterranean Moroccan coast. The study is based on samples taken from commercial catches in M’diq Bay. The spawning period was determined following both the monthly changes of the gonadosomatic index and the histological maturity stages. The Atlantic chub mackerel spawn between November and March, with maximum activity in December