Morphological characterization of bale and west arsi coffee (Coffea arabica L.) Collections at gera, southwest ethiopia

Abstract

Morphological characterization of coffee accessions is a precondition for the improvement of coffee varieties for yield and disease resistance. A total of 133 coffee accessions collected from Bale and West Arsi zone were characterized using morphological traits to estimate the extent of variability among the collection at Gera Agricultural Research Sub Center along with four standard checks. The experimental treatment was laid using an augmented design with three blocks of single row with six trees per plot. The experiment was superimposed during 2018/19 cropping seasons on four years old coffee trees which was planted in July, 2015. Data on 25 quantitative and 12 qualitative traits was recorded from three representativ e trees per plot. The analysis of variance revealed a significant (P<0.05) difference among the collections for most of the quantitative traits considered. The highest (2886.33 kg/ha) and lowest (20.31 kg/ha) mean bean yield was recorded from accession B184/07and B77/07, respectively. Higher mean yield coupled with resistance to CBD were recorded from accessio n B184/07 and B29/07.Genotype variations were greater than environmental variation for all traits except plant height and number of secondary branches. Higher percent (%) and closer variation of GCV and PCV value were demonstrated by traits such as coffee leaf rust, coffee berry disease, bean yield and number of secondary branch and percent of bearing primary branch. High estimates of heritability and genetic advance as percent of mean were observed for coffee leaf rust, coffee berry disease, number of secondary branch, percent (%) of bearing primary branch, bean yield and height up to first primary branch. Coffee yield was positively and significantly correlated with percentage (%) of bearing primary branch (rg=0.64), coffee leaf rust (rg=0.39) and canopy diameter (rg=0.39). Fruit thickness, canopy diameter, height up to primary branch, percentage of bearing primary branch and coffee leaf rust exhibited positive direct effect with coffee yield. Cluster analysis based on quantitative characters grouped the accessions into six clusters of different size. The higher inter cluster distance were observed between clusters II and VI (142.82), followed by cluster I and VI (100.94). Principal component analysis with eigenvalue greater than one exhibited 70.55 % of the total variation, and the highest contribution of traits for total variation accounted by the first and second principal components with respective value of 25.88% and 20.86%. Accordingly, fruit length (0.75%), fruit thickness (0.87%), fruit width (0.86%), coffee berry disease (0.42%) and number of secondary branch (0.32%), % of bearing primary branch (0.39%) and canopy diameter (0.42%) had more contribution to the total variation. Shannon-waver diversity index (H’) for different qualitative traits showed existence of diversity for stipule shape, fruit shape, leaf tip color, fruit color, growth habit, leaf shape, angle of insertion, leaf apex shape and branching habit. Generally, the result of the study showed existence of significant genetic vari ability among tested genotypes.