Population genetics of Mesembryanthemum crystallinum in Egypt.
Genetic diversity plays an important role in any long term management planning of a species. Mesembryanthemum crystallinum has been naturalized in disturbed regions along the Mediterranean coast competing with native plants. The levels and pattern of the genetic variation within and among its populations along Deltaic Mediterranean coast of Egypt was investigated using random amplified polymorphic DNA (RAPD). Forty-two samples representing nine populations of M. crystallinum were collected. The results showed that %PPB values for a single population ranged from 9.14% to 28.91% with an average of 19.76%. The average of Shannon information index (SI), expected heterozygosity (He) and unbiased expected heterozygosity (uHe) values were 0.098, 0.064 and 0.072, respectively. According to AMOVA analysis, 9% of the total genetic structure was attributable to regional divergences and 38% to population differentiation within regions and 53% differences among individuals within populations. Mantel test showed a low correlation (r2 = 0.001) between the studied populations. The dendrogram exhibited two clusters of populations which were confirmed by principal coordinate analysis (PCoA). The study concluded that M. crystallinum has lower levels of diversity than other plant species with similar life history characteristics and high genetic differentiation among population.