SYNTHESIS AND ASSESSMENT OF DATE PALM GENETIC DIVERSITY STUDIES
Keywords:Cultivar characterization, Genetic diversity, Germplasm, Molecular markers, Phenotype, Population differentiation
A thorough assessment of genetic diversity and population differentiation of Phoenix dactylifera are critical for its dynamic conservation and sustainable utilization of its genetic diversity. Estimates of genetic diversity based on phenotypic, biochemical and molecular markers; and fruit quality traits were utilized in assessing the population differentiation of date palm populations throughout its center of diversity. Some phenotypic traits may not exhibit variation in response to environmental or management factors and can be used as stable descriptors of date palm cultivars and for cultivar identification. The majority of analyzed studies based on isozyme and microsatellite markers, reported larger within-population than among-population genetic diversity levels. Most variation estimated for fruit quality traits was found among populations; however, substantial differences in genetic diversity components were found among and within populations. The overall partitioning of genetic diversity, based on phenotypic, biochemical, molecular, and fruit quality traits suggested that date palm cultivars represent a complex gene pool within which historical movement of germplasm, recent introductions and human selection are shaping their genetic structure. The empirical evidence derived from this assessment suggested that the genetic structure of date palm populations is controlled by the environment, isolation by distance, and the biological characteristics of the tree.