Abstract:
Arabica coffee (Coffea arabica L.) is an economically important crop, which is contributing the highest of
all export revenues in Ethiopia. There has been no systematic diversity analysis carried out in Limu coffee
germplasm accessions. Thus, the over all objective of this experiment was to characterize and estimate the
extent of genetic variation and correlations between pairs of morphological and organoleptic characters.
Forty nine Coffee arabica accessions from Limu Kossa Wereda (Jimma) were planted in simple lattice
design. Analysis of variance indicated the presence of significant (P<0.05) variability of coffee accessions
for most of quantitative traits. However, the results not indicated variation for characters such as stem
diameter, canopy diameter, average internode length of stem, average length of primary branches, average
internode length of primary branches, number of primary branches, and percentage of bearing primary
branches. Principal component analysis grouped 22 quantitative characters in to ten uncorrelated
components. About 85.74% of the variation present among accessions was explained by ten principal
components. Clustering analysis grouped the accessions in to four genetically divergent classes based on
the average similarity value for quantitative characters. Magnitude of genetic and environmental
variations explaining a given trait was found different. Accordingly, high broad sense heritability value
was obtained for most of quantitative characters. However, canopy diameter (1.51%), average internodes
length of stem (0.09%), average length of primary branches (16.03%) and percentage bearing primary
branches (10.3%) showed low. Mean square for organoleptic traits indicated the presence of significant
(P<0.05) variations among coffee accessions for cup quality attributes studied except aromatic intensity,
bitterness, astringency, and body. Cluster analysis based on coffee quality traits grouped 49 coffee
accessions into three genetically divergent and three uncorrelated principal components. Shannon diversity
values were variable among qualitative traits. Traits such as growth habit, leaf shape, stipule shape and
fruit shape showed high level of diversity for most of collection sites. Over all, the study confirmed the
presence of trait variation in Limu coffee accessions and this could be exploited in the genetic improvement
of the crop through hybridization and selection.
