Biodiversity, genetic diversity, and genetic resources of date palm

Abstract

Phoenix dactylifera L. is composed of genetically discrete clones representing thousands of cultivars without the benefi ts of a dynamic mutationrecombination system; its genetic resources are the most important component of biodiversity in its natural habitats; these include modern cultivars, landraces, obsolete cultivars, breeding lines, and related wild species. Cultivated Phoenix is closely related to a variable aggregate of wild and feral palms distributed over a wide desert belt across the Middle East and North Africa. Genetic diversity and genetic structure of the species gene pool complex have been shaped and greatly altered by human and natural selection, clonal propagation, and spatiotemporal exchange of germplasm. The mixed sexual-clonal propagation system acted on the sexual traits, impacted the genetic structure of populations, and may have resulted in the accumulation of domesticated traits in the date palm. Traditional oases continue to play a vital role in the maintenance and enrichment of date palm biodiversity, genetic diversity, and genetic resources through multiple processes and dynamic conservation practices. However, with the advent of modern plantations emphasizing elite cultivars, a better understanding of the intraspecifi c genetic variation of date palm and its distribution in oasis agroecosystems is essential for the conservation and sustainable utilization of its biodiversity and genetic resources. In-depth assessment of the genetic vulnerability of date palm to biotic and abiotic stress requires knowledge of the extent and distribution of its genetic diversity, both of which depend on the species evolution and its unique breeding system, past genetic bottlenecks, and ecological, environmental, and anthropogenic factors.