Genetic Diversity of Wild Coffee (Coffea Arabica L.) Populations from Southwestern Ethiopia as Revealed by ISSR Markers
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Date
2012-06
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Addis Ababa University
Abstract
Coffea arabica L., is indigenous to the highland of southwestern Ethiopia and southeastern
Sudan. It is the afromontane rain forest species of south west and south east part of Ethiopia and
grown naturally at altitudes ranging from 1,300 and 1,800 meter above sea level. Human
population pressure and land use change in and around the afromontane rain forest highly
threatened the wild coffee populations of Ethiopia. Inter simple sequence repeats (ISSRs)
molecular markers were analysed. In the present study five wild populations of Coffea arabica
from, Bench Maji-1(Maji), Bench Maji-2(Jeba), Dawero Banja, Limmu and Anfilo were
included. A total of 71 individual plants were analyzed using four ISSR primers, three
dinucleotides (810, 812,818) and one penta nucleotides (880) primers. A total of 30 clear and
reproducible bands were amplified, and 100% were found to be polymorphic. The highest
polymorphic loci were revealed by primer 812 with 9 polymorphic loci. Among the populations
studied, Bench Maji-1 and Dawero showed 100% polymorphism, while Limmu and Anfilo
showed moderate polymorphism of 56.67% and 63.33%, respectively, whereas Bench Maji-
2showed the least polymorphism(30%). The average gene diversity relative to the overall
population was 0.45. AMOVA without grouping revealed that higher percentage of variation
(79.4%) is attributed to the within population variation while the remaining variation is due to
the among population variation (20.6%). Forest based UPGMA analysis based on Jaccard’s
coefficient revealed one major group with Limu and Anfilo and two outliers (Bench Maji and
Dawero Banja). NJ analysis based on individuals of wild Coffea arabica showed two distinct
major clusters and sub-clusters within both major clusters; and individuals from Bench Maji-1
and Anfilo tend to form their own separate groups while others tends to speared all over the tree.
In 3D PCO, most of Dawero Banja and Bench Maji individuals were intermixed with each other
and made separate group from the other two populations but individual of Anfilo and Limmu
were spread all over the plot.
Key words: Coffee, Coffea arabica, genetic markers, genetic diversity and ISSR
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Keywords
Coffee, Coffea arabica, genetic markers, genetic diversity and ISSR