Date Palm

Dr. Sakina Elshibli
Department of Agricultural Sciences
University of Helsinki, Finland

Biodiversity in date palm
(Phoenix dactylifera L.)

Abstract: Date palm, is a multipurpose
tree cultivated for thousands of years for
its high nutritional, economic and ecological values. The large numbers of date
palm cultivars, with a wide range of distinct morphological diversity, have been
atarget of considerable research work,
including studies on both phenotypic as
well as genetic diversity. In this paper, the
biological nature, values and distribution
of date palm tree were introduced and the
existing knowledge of date palm biodiversity is reviewed. High genetic as well as
compositional and morphological diversity were detected within and among date
palm germplasm from widerange of production areas. This diversity constitutes a
wealth that needs to be well-recognized
and maintained for evolutionary responses in a changing environment. Cultivar
identification needs, beside the morphological characters, development of proper
markers that may assist in identifying and
screening cultivars at early stages of de58

velopment considering the genetic basis of
thesecultivars.
Keywords: date palm, Phoenix dactylifera, biodiversity, genetic diversity, phenotypic diversity, dates
1. Introduction
Biodiversity or biological diversity
comprises three main elements, namely
genetic diversity, organismal diversity and
ecological diversity (Frankel et al. 1995;
Gaston and Spicer 2004). Each of these
elements has own different components
which can be arrangedin hierarchical order; such as from individual living organism to a species. Diversity within plant
species includes genetic diversity and phenotypic diversity. Genetic diversity represents heritable variation within and between individuals or populations of plant
species. Phenotypic diversity represents
the interaction effect between genetic and
environmental diversities and is an appar-Figure 1. Date palm trees along the Nile River bank in northern Sudan. Photo by the Author.

ent indicator of organismal diversity. This
diversity is very important and represent
the basis for selection and conservation
as well as for plants improvement for sustainable utilization, which in turn, essential for present and future of human wellbeing (Ford-Lloyd and Jackson 1986). It
is necessaryto understand the existing distribution and extent of a species diversity
for proper conservation and utilization.
Date palm as an important tree species of
dry lands has been a target of considerable research work, including studies on
both phenotypic and genetic diversity. The
aim of writing this paper is to introduce
date palm tree and to review the existing
knowledge of date palmbiodiversity.
2. Date palm tree
Date palm (Phoenix dactylifera L.) is a
multipurpose tree, with a long history of
cultivation and utilization in north Africa

and Middle East for at least 5 000 years.
Date palm is a diploid (2n=36), perennial,
monocotyledonous plant. Being a dioecious species in character, date palm has
separate male and female individuals. Female trees are cultivated mainlyfor their
nutritive fruits, while one male may considered sufficient to pollinate 50 female
palms (Zaid and de Wet 2002a). Although
the average economic life of a date palm
tree is estimated to be up to 50 years, the
tree may stay productive up to 150 years
(Chao and Krueger 2007).
Date palm can reproduce both sexually
and asexually. Date palms are cloned by
separating and independentlyestablishing the offshoots produced by individual
trees. This method maintains the genetic
integrity of date palm cultivars. Offshoots
are produced in limited numbers during
a date palm’s life span (Zaid and de Wet
59

2002b). Numbers of produced offshoots
vary greatly among cultivars with the typical range being 20-30. However, not all
offshoots succeed to make roots and survive (Zaid...