Patterns of genetic diversity in North Africa: Moroccan-Algerian genetic split in Juniperus thurifera subsp. africana.

Juniperus thurifera is a key element of the forest communities in arid and semi-arid areas of the western Mediterranean. Previous genetic and morphological investigations suggested that Algerian populations are genetically more similar to European than to Moroccan populations and advocated their recognition at the variety rank. We aimed to investigate the spatial genetic structure in J. thurifera to verify the distinct character of the Algerian population in terms of the genetic breaks reported among several North African taxa. We also modelled species distributions since the Eemian to recognise the impact of past climatic changes on the current pattern of diversity and predict possible changes in species distribution in the future. Species-specific microsatellites were used in the analysis of 11 populations from Algeria, Morocco and Europe. We revealed the significant genetic distinctiveness of the Algerian populations from the Moroccan and European stands that may have important taxonomic and conservation implications. The diversity pattern revealed for J. thurifera reflects the east-west genetic splits reported among some North African plant and animal taxa and suggests an impact of shared historical processes. Additionally, modelling of the distribution allowed us to identify possible glacial refugia and their impact on the modern pattern of differentiation in J. thurifera. Reduction of species occurrence, especially in the European domain, is likely according to the future projections of the species distribution.

Genetic variation and structure of maize populations from Saoura and Gourara oasis in Algerian Sahara.

BACKGROUND: The ability of maize populations/landraces to tolerate drastically extreme environments over the past four centuries in Algeria leads to characterize these genetic resources for germplasm management as well as the identification of the best landraces useful for genetic improvement. Thus, the aim of the present work was a fingerprinting of an Algerian maize collection (47 landraces) from Saharan oasis by using 24 agro-morphological traits and18 Simple Sequence Repeats to evaluate genetic diversity and population structure. RESULTS: Phenotypic traits showed large significant variation in which earliness, plant size, ear and kernel features and crop yield appeared the most discriminant traits among landraces by using principal component analysis (PCA). One hundred ninety-seven different alleles were detected with a high mean number of allele per locus (10.9). The selected SSR were highly informative with PIC values > 0.65 as well as an overall genetic diversity (0.47) highlighting a broad genetic variability in the analyzed landraces. Genetic structure analysis revealed a high genetic differentiation among the 47 maize landraces with an overall Fst value (0.33). Cluster analysis for morphological traits as well as for SSR markers grouped the 47 Algerian populations regardless their geographic origin. CONCLUSIONS: Maize from Algerian desert harbors a wide genetic diversity offering a source of novel/unique alleles useful for maize breeding programs to face the ongoing and future major challenge, the climate changes.

A simplified Protocol to Induce Callogenesis in Protoplasts of Date Palm (Phoenix dactylifera L.) Cultivars.

BACKGROUND: In Algeria, date palm is currently confronted to the Bayoud disease. Biotechnological tools such as protoplastsfusion can appear as an alternative to ensure rapid multiplication and improvement of this species. OBJECTIVES: Callogenesis induction in protoplasts isolated from embryogenic callus of three date palm cultivars. MATERIALS AND METHODS: Some factors influencing the isolation and culture of protoplasts segregated from the calli of three date palm (Phoenix dactylifera L.) cultivars (Deglet Nour, Akerbouch and Degla Beida) were studied. Protoplasts of each cultivar were cultured on a semi-solid medium supplemented with various hormonal balances. RESULTS: Maceration with an enzymatic solution containing 1.5% cellulase and 1% macerozyme R10 in the presence of 0.5 M mannitol for more than 16 h with gentle agitation allows isolation of a great number of viable protoplasts. In addition, purification of protoplasts on a cushion of 21 or 25% sucrose was effective in cell debris removal and maximum recovery. The culture of isolated protoplasts on a semi-solidified Murashige and Skoog medium, with 0.3% agarose, 2 mg. L-1 2,4-D and 0.5 mg.L-1 BAP allowed good viable protoplast maintenance as well as cell wall regeneration. After more than two months of culture, cell divisions were still occurring and microcalli became visible to the naked eye, containing a large number of cells. CONCLUSIONS: The developed protocol can be useful for application of somatic hybridization to improve date palm cultivars.