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Climatic change manifested by increasing summer drought necessitates the development of drought-tolerant forage grass cultivars. Summer dormancy is a major trait conferring drought survival and autumn recovery of perennial grasses in Mediterranean areas. Moroccan ecotypes of orchardgrass (Dactylis glomerata L.) expressed 67% greater degree of summer dormancy than tested cultivars except the highly dormant 'Kasbah.' Furthermore, summer dormancy was highly correlated with perenniality (r = 0.63, P < 0.01). However, summer dormancy was associated with low productivity. A breeding program was started to develop productive orchardgrass cultivars with high summer dormancy. Hybrids between high- and low-dormancy cultivars produced offspring with combinations of enhanced dormancy and biomass production indicating potential for breaking the negative dormancy-yield association. For example, Kasbah (dormant) × 'Medly' (summer-active) hybrids were 57% more dormant than Medly and 32% higher yielding than Kasbah. Genetic analysis of heritability and molecular markers will provide more information on the genetic control of summer dormancy. Results of crosses between contrasting populations of orchardgrass indicate potential for combining the desirable traits of summer dormancy and high annual herbage yield into an eventual cultivar. [ABSTRACT FROM AUTHOR]

Summer dormancy improves drought survival and autumn recovery of perennial forage species in Mediterranean areas. Morocco has served as a source of germplasm for orchardgrass (Dactylis glomerata L.) breeding, but little is known of the incidence and variability of the summer dormancy trait in Moroccan orchardgrass germplasm. This paper characterizes summer dormancy and summer drought survival in Moroccan ecotypes of orchardgrass. Ten Moroccan ecotypes and the cultivar Kasbah were studied in the field in Guich experimental INRA, Rabat, Morocco. Two trials were conducted in irrigated (to test summer dormancy) and in rainfed conditions (to test drought survival after summer). Under irrigation, Moroccan ecotypes of orchardgrass and Kasbah were summer dormant. According to a summer dormancy index and a combination of physiological responses, most ecotypes and Kasbah were found completely dormant. A single ecotype was considered incompletely dormant. After intense first year summer drought, plant survival was correlated (P < 0.001) with water soluble carbohydrate (WSC) content and osmotic potential in immature leaf bases (r = 0.67 and 0.62, respectively). Two Moroccan ecotypes exhibited higher post-drought survival after summer drought (98%) than Kasbah (90%) (P < 0.01). After a second year with severe drought, an ecotype outyielded Kasbah for autumn recovery (P < 0.001). Moroccan germplasm exhibited good levels of dormancy and agronomic performance that would be desirable in breeding programs. [ABSTRACT FROM AUTHOR]

Origanum compactum L. ( Lamiaceae ) is one of the most popular medicinal and culinary herbs with a long history of traditional use. This species, endemic to Morocco and Southern Spain, is considered as threatened, due mainly to over-harvesting and habitat destruction. Assessment of genetic polymorphism of threatened species constitutes a prerequisite for germplasm conservation. To support and monitor future conservation and management measures, we used 15 microsatellite loci to genotype 670 individuals of O. compactum distributed over 59 localities covering the entire geographic distribution of the species in Morocco. In contrast to what was argued in most previous studies, the genetic diversity of the Moroccan oregano was greater mostly on isolated and declined populations compared to less fragmented accessions. Accordingly, our study identifies the most relevant management units for conservation purposes on the basis of their genetic diversity level. Factors such as the perennity of the species, somatic mutations, or multiple founder events could explain this unexpected level of genetic diversity at the species level in this endangered plant. The population genetic results reflect a strong genetic structure and identify three major clusters among O. compactum populations: a Northern cluster composed of populations near the strait of Gibraltar (Tangier-Tetouan and Chefchaouen regions as well as some adjacent populations from Taounate), and two other clusters with significant mixed lineage. This result supports the hypothesis that the strait of Gibraltar could be a migration route for plants between Southern Spain and Northern Morocco. The high differentiation of populations (Fst = 0.22) and the low rate of gene flow between them (Nm = 0.88) might been caused by recent isolation of the populations through habitat disturbances. Historical demographic patterns inferred with a generalized stepwise mutation model (SSM) and two-phase model (TPM) using maximum likelihood showed significant past demographic changes in 39 of the 59 sampled populations. Implications of these results to develop appropriate conservation strategies of this endangered species are proposed. [ABSTRACT FROM AUTHOR]

Essential oils (EO, 15 collective samples and 47 individual samples) of Thymbra capitata collected from Moroccan Western Rif were analyzed using gas chromatography (GC) in combination with retention indices (RI), gas chromatography-mass spectrometry (GC-SM) and 13C NMR spectroscopy. Twenty components were identified. Carvacrol (68.2%-85.9%) was by far the major component of all the samples, while the content of thymol (0.1-0.3%) was very low. Other components present in appreciable amounts were gamma-terpinene (up to 8.9%), p-cymene (up to 7.1%), linalool (up to 4.4%) and (E)-beta-caryophyllene (up to 4.1%). In contrast, the yield of EO varied drastically from sample to sample (0.5-3.7%). No correlation could be established between yield of EO and altitude, pH, chemical composition and granularity of the soil. Cultivation under controlled conditions is suggested to improve the quantitative characteristics of carvacrol-rich Moroccan T. capitata.