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A study to explain the spatial genetic structure and the dynamics of the Laperrine's olive (Olea europaea subsp. laperrinei), a long-living tree from the central Saharan mountains is presented. The study proves that long distance gene flow gets highly limited by the desert barriers.

Date palm (Phoenix dactyliferaL.) is the mainstay of oasis agriculture in the Saharan region. It is cultivated in a large part of the Mediterranean coastal area of the Sahara and in most isolated oases in the Algerian desert. We sampled 10 oases in Algeria to understand the structure of date palm diversity from the coastal area to a very isolated desert location. We used 18 microsatellite markers and a chloroplast minisatellite to characterize 414 individual palm trees corresponding to 114 named varieties. We found a significant negative inbreeding coefficient, suggesting active farmer selection for heterozygous individuals. Three distinct genetic clusters were identified, a ubiquitous set of varieties found across the different oases, and two clusters, one of which was specific to the northern area, and the other to the drier southern area of the Algerian Sahara. The ubiquitous cluster presented very striking chloroplast diversity, signing the frequency of haplotypes found in Saudi Arabia, the most eastern part of the date palm range. Exchanges of Middle Eastern and Algerian date palms are known to have occurred and could have led to the introduction of this particular chlorotype. However, Algerian nuclear diversity was not of eastern origin. Our study strongly suggests that the peculiar chloroplastic diversity of date palm is maintained by farmers and could originate from date palms introduced from the Middle East a long time ago, which since then, hasbeen strongly introgressed. This study illustrates the complex structure of date palm diversity in Algerian oases and the role of farmers in shaping such cryptic diversity.

Background: The Phoenix dactylifera L. (date palm) is known for its traditional medicinal properties across the history of native population in Algerian Sahara. There is a large trend of consumption of date palm pollen preparations in many human infertility cases in our country. However, the validity has not been scientifically tested. There has been no direct scientific research on this application. This study was undertaken to identify cultivars with greater potential in the traditional medicine uses. To evaluate the effects of date palm pollen on some sexual behavioural parameters of male adult rats, we tested the role of pollen powder from Deglet Nour cultivar on some male reproductive parameters., Materials and Methods: An Ethnobotanical survey was conducted in 17 oases in southern Algeria to identify all cultivars with medicinal interest. Local people were interviewed with open questions. A questionnaire and personal interviews for data collection were designed to record important cultivars, parts used and preparations. To determine the active constituents of date palm pollen used in traditional medicine, a phytochemical screening was performed. The effects of oral administration of date palm pollen suspension on male adult rats were investigated on body and testicle weights, serum testosterone level., Results: 131 prominent cultivars were found within 12 cultivars containing various parts with medicinal effects. Some primary and secondary metabolites were detected by phytochemical screening. The pollen increased the weight of the body, testicles and enhanced the serum testosterone level of male rats treated., Conclusion: The present survey has provided the identification and recognition of date palm cultivars used in traditional Saharan medicine. Date palm pollen could improve sexual activities in male infertility cases and may be attempted to derive drugs.

In the present central Saharan conditions, the Laperrine's olive regeneration has never been observed and its populations are locally threatened. The production of plants originating from seeds was proposed as a multiplication strategy. In order to determine the impact of sexual reproduction, seeds issued from ten mothers (sampled from four locations in the Hoggar, Algeria) were genotyped using microsatellites. Compared to the initial population, a significant lost of allelic richness was revealed, indicating that our seed sampling was not representative of the local gene diversity. Paternity analyses allowed measurement of the effective pollen-mediated gene flow within patches. Preferential mating between some genotypes was revealed. A trend for a higher multipaternity on seeds collected on trees from relatively large patches was also observed. Lastly, seedlings issued from trees of small patches displayed low growth performance. The implications of our observations in the development of an efficient conservation strategy by seeds are discussed.

We report here for the first time callus formation from protoplasts in date palm (Phoenix dactylifera L.). Protoplasts were isolated from young leaves of offshoots and embryogenic calli in Deglet nour and Takerboucht genotypes. The protoplast yield depended on genotype, donor plant material, mixture of enzyme solution, and incubation time. With regard to the donor material, the best response was obtained with callus. Cell division was induced in both liquid culture and nurse culture. The best donor material for cell division was callus and the best response was obtained with the feeder layer, which induced a division rate of 30% in Deglet nour and 15% in Takerboucht genotypes. The dividing cells developed to microcalli on the feeder layer; the microcalli developed to calli on modified MS medium; however, the calli failed to regenerate into roots or shoots.