Comparison of the effectiveness of ISSR and SSR markers in determination of date palm (Phoenix dactylifera L.) agronomic traits

Abstract Date palm (Phoenix dactyliferaL.) is extensively cultivated in the Middle East and in North Africa. Seven ISSR markers and five SSR loci were selected and used to evaluate genetic diversity in twenty-six Tunisian cultivars. ISSR primers amplified a total of 43 polymorphic DNA fragments. The average was 6.1 fragments per primer. The microsatellites examined in this study were highly polymorphic possessing a great number of alleles with an average of 7.2 alleles per locus. Principal component analyses based on Nei Genetic distances showed groups of cultivars with a common maturity period and a common fruit consistency. SSR markers discriminate the fruit characteristics subpopulations in a more convincing way than ISSR markers. The Mantel test emphasizes a significant correlation between genetic distance and fruit consistency. A significant difference was observed between soft and dry subpopulations using ISSR data and between semisoft and the other fruit consistency subpopulations using SSR data

Molecular and morphological analyses of date palm (Phoenix dactylifera L.) subpopulations in southern Tunisia

Phoenix dactylifera L. is widely distributed and performs an important socioeconomic role in the south of Tunisia.The objective of this work was to evaluate different methods of estimating the diversity and genetic structure of Tunisiandate palm subpopulations. Nine morphological traits and five SSR loci were used to study morphological and genetic diversity. Correlations between phenotypic and genetic distances were assessed. Analyses of variance of the morphological data reveal significant differences among subpopulations for all traits measured. The Mantel test shows that morphological variation is correlated with fruit maturity period (r = 0.161; p = 0.020). Analysis of molecular variance reveals significant genetic variation among fruit-consistency subpopulations (p < 0.05) and the Mantel test emphasises a correlation between genetic distance and fruit consistency (r = 0.110; p = 0.029). This information will be useful for germplasm collection, for conservation and for various date palm culture programmes in the Tunisian continental oases.Phoenix dactylifera L. tiene una distribución amplia y una importante función socioeconómica en el sur de Túnez.El objetivo de este trabajo fue evaluar los diferentes métodos de estimación de la diversidad y la estructura genéticade las subpoblaciones de palmera datilera de Túnez. Se utilizaron nueve características morfológicas y cinco loci SSRpara estudiar la diversidad morfológica y genética, y se evaluó el nivel de correlación entre las distancias fenotípicasy genéticas. El análisis de varianza de los datos morfológicos reveló diferencias significativas entre las subpoblaciones para todos los caracteres medidos. La prueba de Mantel mostró que la variación morfológica se correlacionó con el período de maduración de las palmeras (r = 0,161; p = 0,020). El análisis de varianza molecular reveló una variación genética significativa entre las subpoblaciones clasificadas por su consistencia del fruto (p < 0,05) y la prueba de Mantel destacó la correlación entre la distancia genética y la consistencia del fruto (r = 0,110; p = 0,029). Esta información será útil para la recolecciones y conservación de germoplasma y los diversos programas de cultivo de la palmera datilera en los oasis de Túnez continental