Coconut - Genomics of Cultivated Palms - page 13

Table 2.1a Molecular and Biochemical Markers in Coconut: RAPD Markers

Primers Used Germplasm/Materials Conclusion Reference

14 primers mostly
OPA series

14 populations of
Pacific Islands

Pattern of continuous
variation but 2
southern groups with
domesticated type;
northeastern group
with wild type fruits

[8]

80 primers
(Operon AH,
OP, A, C, M
series) 16
polymorphic

28 palms of 3 yellow
dwarfs (Malayan [MYD],
Andaman [AYD], and
Kulasekaram [KYD])

Greater diversity within
accessions than
between accessions;
MYD is putative origin
of other 2 dwarfs;
KYD16
individual is distinct

[9]

8 primers mostly
from OPA, B,
C series

81 palms of 20 accessions
(15 from India, 5 from
Indonesia, Philippines,
Malaysia)

Narrow diversity in
Indian accessions,
tall genotypes high
heterogeneity; dwarfs
did not cluster together

[10]

45 primers
(Operon C,
M, E, and
BE series)

33 accessions from all
coconut-growing
continents

Five informative primers:
OPE6, OPC13, OPF14,
OPM2, and OPM17;
high diversity in New
Caledonian accessions

[11]

Niu Leka, or Fiji dwarf, is the third type of dwarf; it is cross-pollinated and has
large fruits but compact stems with short nodes. The genetic nature of the Fiji dwarf
is elaborate [20] along with unique microsatellite allele possessed by the cultivar.
A standard three- or four-letter abbreviation delineates coconut cultivars by their
geographical origin and habit. The last letter in the abbreviation denotes the habit
of the cultivar. For example, RIT refers to the tall cultivar of Rennell Island in the
South Pacific, known as Rennell Island Tall. Coconut populations are broadly clas-
sified in five groups, based on their geographical origin, as South Asia, Southeast
Asia, African, South Pacific, and Latin American and Caribbean. Foliar polyphenols
[28] and their components are found to be a reliable indicator of geographical ori-
gin of the coconut. Coconut populations on a coast are similar to each other com-
pared to those on other coasts, although they may be located on the same continent.
West African coconut populations on the Atlantic coast [29] are genetically proximal
to those in Mexico on the Atlantic coast. The highest level of genetic diversity with
the polymorphic microsatellite alleles [19] and RAPD assay [8] is seen in Pacific
Island talls. Most of the molecular marker studies confirmed the heterogeneity in
tall coconut populations and their differentiation from homogenous dwarf popula-
tions [9,11,13,22] . Three different SSR marker kits are available and being used for