Submitted to: Encyclopedia of Life Support Systems
Publication Type: Book / Chapter
Publication Acceptance Date: 6/1/2011
Publication Date: 6/25/2011
Citation: Jaradat, A.A. 2011. Biodiversity of date palm. In: Encyclopedia of Life Support Systems: Land Use, Land Cover and Soil Sciences. Oxford, UK: Eolss Publishers. p. 1-31.
Interpretive Summary: The date palm is the dominant component upon which the oasis agro-ecosystem is based. Besides its unique nutritional, biochemical, and biophysical characteristics, the date palm tree is a rich source of aesthetic and cultural values. It is the only indigenous wild desert plant domesticated in its native harsh environment. The tremendous advantage of the date palm tree is its resilience, its long-term productivity, and its multipurpose attributes. However, some of its unique characteristics (i.e., slow growth, slow offshoot-based propagation system and the difficulty of predicting adult characteristics of the seedlings) have restricted its improvement in the past. Man-made selection acted on the genetic diversity available in the wild progenitor of the date palm to increase yield, fruit size and palatability; reduce branching; facilitate vegetative propagation; and maintain genetic integrity of date palm cultivars. The evaluation and conservation of date palm genetic resources are imperative, especially where the genetic diversity has not been previously identified, characterized and evaluated. A biodiversity-based paradigm for sustainable agriculture in oasis agro-ecosystems is potentially the most cost-effective and durable solution for the problems associated with environmental stresses. Future advances in developing elite date palm cultivars will depend on the identification or development of molecular and phenotypic markers that may assist in identifying economically and agronomically important traits and cultivars. The future of date palm largely depends on developing advanced knowledge and information about the dynamics, management, and sustainability of the oasis agro-ecosystem, and in-depth understanding of the genetic diversity of the date palm and its wild relatives. The information on date palm biodiversity will help planners, scientists and farmers ensure that the oasis agro-ecosystems are sustainable by being resilient to future changes in global climate, markets, and other social and economic pressures, and the outlined strategies for conservation and sustainable use of date palm biodiversity. If properly designed and implemented, changes will result in integrated protection of environmental resources of the fragile oasis agro-ecosystems.
Technical Abstract: The date palm (Phoenix dactylifera) is the dominant component upon which the sustainable biophysical and socio-economic structures of the oasis ecosystem are based; a fruit tree with unique nutritional, biochemical and biophysical characteristics, a rich source of aesthetic and cultural values, and a genetic resource. The date palm is the only indigenous wild desert plant definitely domesticated in its native harsh environment. Along with the camel (Camelus dromedarius), the date palm was responsible for opening the vast desert territories for human activity and the development of oasis agro-ecosystems. The oasis represents the climax of rigorous management of scarce water and land resources in alliance with the date palm. Phoenix dactylifera is composed of genetically-discrete clones representing thousands of cultivars without the benefits of a dynamic mutation-recombination system. It is closely related to a variable aggregate of wild and feral palms distributed over a desert belt across the Middle East and North Africa. Genetic diversity and genetic structure of the gene pool complex of date palm have been shaped and greatly altered by natural and human selection, clonal propagation, and spatio-temporal exchange and movement of germplasm. Traditional oases continue to play a vital role in the maintenance and enrichment of date palm genetic resources and genetic diversity through multiple processes and dynamic conservation practices. However, a better understanding of the intra-specific genetic variation of date palm and its distribution in oasis agro-ecosystems is essential for the conservation and sustainable use of its biodiversity. If properly designed and implemented, strategies for conservation and sustainable use of date palm biodiversity will minimize anthropogenic disturbance, interference and impact, optimize ecosystem functions, and result in integrated protection of environmental resources of fragile oasis agro-ecosystems. Sustainability and provision of multiple services of these ecosystems depend largely on a highly diverse genetic base of date palms. In-depth assessment of the genetic vulnerability of date palm to climate change, desertification and salinity stress requires knowledge of the extent and distribution of its genetic diversity, both of which depend on the species evolution and unique breeding system, past genetic bottlenecks, and ecological, geographical and anthropogenic factors.