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Molecular Plant Breeding 2011, Vol.2, No.12, 83
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91
http://mpb.sophiapublisher.com
83
Research Letter Open Access
Genetic Diversity of Coconut Cultivars in China by Microsatellite (SSR)
Markers
Xiaolei Liu
1,2
, Hua Tang
1
, Dongdong Li
1
, Liheng Hou
2
1. Key Laboratory of Tropic Biological Resources of Ministry of Education, Hainan University, Haikou, 570228, P.R. China
2. Plant Protection and Quarantine Station of Hainan Province, Haikou, 570203, P.R. China
Corresponding author email:
liddfym@hotmail.com;
Author
Molecular Plant Breeding, 2011, Vol.2 No.12 doi: 10.5376/mpb.2011.02.00012
Received: 19, May, 2011
Accepted: 04, Jul., 2011
Published: 00, Jul., 2011
This is an open access article published under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and
reproduction in any medium, provided the original work is properly cited.
Preferred citation for this article:
Liu et al., 2011, Genetic Diversity of Coconut Cultivars in China by Microsatellite (SSR) Markers, Molecular Plant Breeding Vol.2 No.12 (doi:
10.5376/mpb.2011.02.0012)
Abstract
Assessment of genetic diversity is an essential component in germplasm characterization and utilization. In this study, we
determined genetic diversity of 10 coconut (
Cocos nucifera
L.) accessions from six locations in Hainan province, China by using
microsatellite markers. From the used 26 simple sequence repeat (SSR) markers, we detected a total of 188 alleles with an average of
7.23 alleles per locus and an average polymorphism information content of 0.575. Expected heterozygosity (
He
) of Haikou green Tall
(HK-GT) was significantly higher than that of other Tall types, while the lowest heterozygosity was observed in Sanjiang green Tall
(SJ-GT). At the genetic differentiation index (
Fst
) of 0.078, they showed a low level of population differentiation. In addition to
diversity parameters, Bayesian assignment tests and cluster analysis were used to determine population structure. Our study provided
a better understanding of individual identities, genealogical relationships and geographical origin of coconut germplasm, and it could
contribute to more efficient conservation and utilization of this germplasm.
Keywords
Coconut cultivar; Simple sequence repeat (SSR); Genetic diversity; Hainan
Background
The coconut palm (
Cocos nucifera
L., Arecaceae) is
the most widely cultivated crop in Philippines,
Indonesia, India, Sri Lanka and China, where coconut
palm plays an important role in economy. It provides
food supply and industrial products, such as coconut
oil, copra, liquid endosperm and desiccated coconut.
Almost every part of the coconut tree can be used in
either making commercial products or meeting the
food requirements of rural communities (Teulat et al.,
2000). Coconut palms play an important role in the
economy of Hainan province, directly providing food
and income from coconut products. Moreover, it can
be indirectly used as important features of the
landscape, where tourism is a major component in the
economy. The planting area of coconut is 43,300
hectares across Hainan Island as both economic and
ornamental plants, and its yield is about 214 million
coconuts (Guo, 2005, http://www.fao.org/docrep/010/
ag117e/AG117E07.htm). However, coconut cultivation
is confronted with a relative decline in many countries
as the explosive competition from other oil crops, the
increased demand of timber, drought, pest, disease and
low fertility of the soils. Furthermore, the slow growth
and long pre-breeding period of palm inhibit the
genetic enhancement of coconut palm for productivity
and tolerance to biotic and abiotic stresses (Rajesh et
al., 2008). Germplasm collections, containing significant
amount of genetic diversity within and among coconut
populations, are essential for an effective crop
improvement. Therefore, the assessment of genetic
diversity within coconut populations becomes
increasingly significant in germplasm conservation
and utilization.
Investigation of coconut genetic diversity provides
sufficient scientific data for germplasm management.
Diversity analysis in coconut palm has been done by
morphological traits, biochemical and molecular
markers. Morphological and biochemical markers
have shortages as follows: Long juvenile phase, high