Genetic Diversity of Wild Populations of Arabica Coffee (Coffea Arabica L.) in Yayu Forest of Ethiopia Using Inter-Simple Sequence Repeat (Issr) Marker
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Date
2006-07
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Addis Ababa University
Abstract
Arabica coffee (Coffea arabica L.), which contributes over 70 percent of the world's coffee
productions, is characterized by a low genetic diversity, attributed to its allopolyploidy origin,
predominately self-pollinating nature and its recent evolution. A total of 81 wild coffee trees from
four populations of Yayu (Geba-Dogi) forest and Sore forest (only thee samples for comparison)
were used to assess the within and among populations genetic diversity using inter-simple
sequence repeat (ISSR) marker. Two populations (Yayu-1 and Yayu-2) are from disturbed region
of the forest and two populations (Yayu-4 and Yayu-5) are from undisturbed region of the forest.
The samples range in age from about 2 years old to very old trees. Larger genetic diversity
estimate was observed for Yayu-2 (P=27.27%, H=0.079, H’j=0.175) and lower for Yayu-4
(P=10.91%, H=0.31, H’j=0.07). Individuals in disturbed regions are clearly distinguished from
those in undisturbed regions on dendrogram generated based on Jaccard similarity coefficient
and unweighted pair-group method using arithmetic averages (UPGMA). Smaller genetic
distance exists between Yayu-1 and Yayu-2 (0.011) and larger genetic distance exists between
Yayu-1 and Yayu-4 (0.109). Larger proportion of the total genetic diversity exists within
population (above 55%), which is the pattern for populations with mixed-mating. The results of
the present study suggest that coffee populations in the semi-disturbed regions of the forest have
higher genetic variability and need to be given priority for both in situ and ex situ conservation
as well as for breeding purposes. Those from undisturbed populations should also be conserved
as they may have some unique genes.
Key words: Coffea arabica, ISSR, Yayu, intraregional diversity, Ethiopia
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Keywords
Coffea arabica, ISSR, Yayu, intraregional diversity, Ethiopia