Biology Reference
In-Depth Information
seedlings of both the species and their intermediate types are present in the islands
in abundance. Operon RAPD primers, especially OPM08 and OPK14, which have
species-specific bands, are helpful to discriminate the seedlings
[5]
.
RAPD markers were used to characterize the diversity of germplasm of Egypt
[6]
,
Jordan
[7]
, Saudi Arabia
[8]
, and Morocco
[9]
. High genetic diversity in Tunisian
germplasm was demonstrated by the use of RAMCO (a combined marker system of
RAPD and ISSR primers) and a set of microsatellite loci
[10]
. A microsatellite kit
for characterizing the date palm diversity was developed using 16 loci
[11]
. These
loci are conserved and cross-transferable to 14 species of
Phoenix
and 6 other gen-
era of palms
[11,12]
. They were used with minor modifications to test lack of gene
flow in
P. atlantica
[13]
and diversity in date palm germplasm native to Algeria
[12]
, Tunisia
[10]
, Sudan
[14]
, and Qatar
[15]
. Genetic diversity of date palm is low
in Morocco
[9]
, Saudi Arabia
[8]
, and Algeria
[12]
but rather high in Tunisia
[10]
mainly due to the history of germplasm or cultivar exchange in the respective coun-
tries. Additional details are provided in
Table 4.1
on the use of markers at species
and in
Table 4.2
on date palm diversity at different geographical locations. A com-
prehensive study of germplasm accession of all the date-growing countries, using a
universal set of RAPD, AFLP, ISSR, and SSR loci, should be undertaken to get a
consensus of the location of biodiversity hot spots.
4.3 Molecular Biology of Sex Determination
Date palm is a dioecious plant with individual male and female trees. The tree
takes 5-7 years to flower, and hence long periods of time are required before the
sex of the plant is known. It is easy to propagate the female trees by offshoots or by
Table 4.1
Molecular Markers for Use in Related Species of Phoenix
Species
Marker Systems
Conclusion
Reference
P. canariensis
,
P.
dactlyifera
, and
intermediate types
54 operon RAPDs
OPM08 and OPK14 gave
species-specific bands
[5]
11 species of
Phoenix
and 4 palm genera
16 nuclear SSR loci
of GA repeat
Cross-transferable to 11
other
Phoenix
species, and
a few were transferable
to
Elaeis guineensis
, 11
species of
Pritchardia
and
Pritchardiopsis jeanneneyi
,
and 6 species
of
Astrocaryum
[11]
P. dactylifera
,
P.
canariensis
,
P. sylvestris
,
P. atlantica
15 nuclear SSR
loci, 1 plastid
minisatellite
P. atlantica
distinct and
isolated for a long time,
with no gene flow
[13]
14 species of
Phoenix
17 SSR loci
Also suitable for 14 other
species of
Phoenix
[12]
