Male diversity matters: genetic structuring of insular male date palm (Phoenix dactylifera L.) revealed valuable breeding and conservation resources

ABSTRACT

Most male date palms available for pollinating different female cultivars have mainly originated from seed propagation resulting in many different local males that represent a source of genetic diversity. Favourable fruit production is related to the quality of pollen and its compatibility with a certain female variety. Therefore, the genetic characterisation of the male progenitors should be the first step to establish a selection programme to produce superior males through different procedures. In this study, the genetic diversity and population structure of 72 male date palm accessions were investigated using 15 microsatellite loci. The highest mean number of alleles per locus was obtained for Tozeur group. Bayesian model-based clustering analysis indicated the presence of two differentiated endemic male date palm genetic clusters, continental and insular, with the presence of introduced accessions originating from the Middle East. The diversity analysis in the insular region of Tunisia, which had never been performed before, revealed that this germplasm enclosed valuable endemic resources supporting the hypothesis of the presence of wild material. These findings are crucial for identifying interesting genotypes that can be integrated into international coordinated actions of Phoenix dactylifera L. breeding programmes and the protection and conservation of valuable resources.

KEYWORDS:

• Date palm
• genetic diversity
• microsatellites
• Island region
• breeding programs

Highlights

1. Two differentiated endemic male date palm genetic clusters, continental and insular, were revealed in Tunisia.

2. The presence of introduced accessions originating from the Middle East is demonstrated.

3. Results attested that the spontaneous uncultivated date palms from the island region are probably wild populations.

4. The role of male diversity in varietal improvement and renewal of less rich and ageing date palm germplasm was attested.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Author contributions

All authors contributed to the study conception and design. Material preparation, data collection and analysis were performed by Hedia Bourguiba, Afifa Hachef and Salwa Zehdi-Azouzi. The first draft of the manuscript was written by Hedia Bourguiba and all authors commented on previous versions of the manuscript. All authors read and approved the final manuscript.

Data availability statement

The data that support the findings of this study are available from the corresponding author, upon reasonable request.

Supplementary material

Supplemental data for this article can be accessed online at https://doi.org/10.1080/14620316.2023.2243950

Additional information

Funding

This work was supported by the Tunisian Ministère de l’Enseignement Supérieur et de la Recherche Scientifique (Project LR99ES12) and the Institut de Recherche pour le Développement (IRD), Montpellier, France.