Genetic Diversity Analysis of Some Ethiopian Specialty Coffee (Coffea arabica L.) Germplasm Accessions Based on Morphological Traits

Abstract

Information on genetic variability is a prerequisite for further improvement of the yield and quality of coffee. However, lack of information on genetic variability for specialty coffee accessions has been one of the major problems in coffee improvement program. Forty nine coffee (Coffea arabica L.) germplasm accessions, which were collected from Gomma Wereda, were evaluated at Agaro research station with the objective of estimating the genetic diversity. The experiment was conducted in simple lattice design with two replications during 2011/12 cropping season by superimposing on six years old coffee trees which were planted in July, 2006 and grown under uniform coffee shade tree (Sesbania sesban) conditions. Data on 26 quantitative characters were recorded. The analysis of variance showed significant (P<0.05) variation among the accessions for all morphological traits except percentage bearing primary branches, leaf area, bean thickness and rust incidence. This indicated the existence of variability among the tested materials. Cluster analysis of quantitative characters grouped the 49 coffee germplasm accessions into five clusters. This makes the germplasm accessions to be moderately divergent. The distances between most of these clusters were highly significant at (P<0.01), suggesting the possibility of getting suitable accessions for hybridization program among the tested materials. Principal component analysis showed the variation in the first two principal components, which explained the lion’s share of the observed variation, (42%), was mainly due to inter node length of main stem and primary branches, leaf length, hundred bean weight, plant height, number of main stem nodes, number of primary branches, length of primary branches, number of secondary branches and canopy diameter. So, these traits were identified as a source variation among Gomma wereda coffee accessions and can be used for selecting diverse parents in future coffee hybridization program.