Phenotypic Diversity in the Hararge Coffee (Coffea arabica L) Germplasm for Quantitative Traits

A field experiment was conducted at Awada Agricultural Research Sub-Center, Ethiopia, to study the magnitude of phenotypic diversity among Hararge coffee (Coffea arabica L.) germplasm accessions based on quantitative traits. A total of 104 entries consisting of 100 accessions from Hararge and 4 standard cultivars were evaluated using nested design. Analyses of variance showed significant differences among the accessions for all the traits considered, indicating the presence of high genetic variability among the Hararge coffee germplasm accessions. Cluster analysis grouped the entries into 6 groups of different sizes, ranging from 5 entries in cluster VI to 44 in cluster III. The maximum inter-cluster distance was obtained between clusters II and VI while the minimum was observed between clusters I and III. Clusters I and V, I and VI, II and IV, II and V, II and VI, III and VI, IV and V and V and VI were significantly divergent. The first four principal components constituted 78.5 percent of the total variation prevalent within the germplasm accessions, while 38.5 percent was represented by the first principal component. The length of the longest primary branch, stem diameter, average length of primary branches, total number of internodes per plant and total number of primary branches per plant were the five important characteristics that contributed most to the total variation in the first principal component, implying that there is high potential to improve these traits through selection. The study revealed the presence of high genetic diversity among Hararge Coffee germplasm accessions and the possibility of developing improved varieties through selection and hybridization. Keywords: Cluster Analysis; Coffea arabica; Genetic Diversity; Germplasm; Hararge; Quantitative Traits East African Journal of Sciences Vol. 2 (1) 2008: pp. 13-1