Genetic diversity of Tunisian male date palm (Phoenix dactylifera L.) genotypes through morphological traits and ISSR markers: new insights for future breeding programs
摘要
The date palm (Phoenix dactylifera L.) is a dioecious plant, with female trees producing dates and male trees, commonly referred to as “Dhokar”, providing pollen. Pollination plays a crucial role in date production, and its success is closely linked to pollen quality and metaxenic effects. Given this importance, selecting male genotypes with superior agronomic traits is essential. However, limited knowledge of male germplasm poses a challenge for breeding programs. Therefore, evaluating the extent of genetic diversity among male date palm is a key prerequisite. The present study investigated both morphological variability and molecular diversity of a set of 30 male genotypes with varying flowering times, all originating from Tunisia. Significant morphological variability was observed across both vegetative and reproductive traits. The principal component analysis based on quantitative traits highlighted morphological similarities among the three flowering groups: Early, full-season and late flowering. In addition, ISSR analysis confirmed the high level of genetic polymorphism, with a mean of polymorphic information content (PIC) of 0.841. The molecular dendrogram showed genotype clustering that was independent of flowering group affiliation. Combined morphological and molecular analyses demonstrated substantial genetic variation within the evaluated male genotypes. These findings contribute valuable insights into the biodiversity of male date palms and support the conservation, utilization and genetic improvement of this underexplored germplasm.