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Estimation of genetic parameters is pertinent as variability within population determines the extent of improvement achieved through crop improvement methods. In view of this, forty-nine coffee (Coffea arabica L.) germplasm accessions, which were collected from Gomma Woreda, were evaluated at Agaro with the objectives of assessing genetic variability, heritability and genetic advance for morphological traits. The experiment was conducted in simple lattice design with two replications. Data on 26 quantitative characters were recorded. The result revealed significant differences (p<0.05) among the accessions for most of the traits studied. The phenotypic coefficients of variation (PCV) was greater than genotypic coefficients of variation (GCV) for all the characters studied, this shows the influence of environmental factors on the characters. Estimates of variability indicated that high phenotypic (PCV) and genotypic coefficients of variation (GCV) were recorded for coffee berry disease (CBD) severity and yield per tree. High heritability was recorded for hundred bean weight (80.21%), number of nodes of primary branches (67.89%), stem diameter (67.16%), height up to first primary branch (66.6%), bean length (62.79%), bean width (61.43%), average inter node length of primary branches (58.33%), angle of primary branches (53.32%), leaf width (52.94%) and canopy diameter (51.95%). The high GAM were recorded for coffee berry disease reaction (88.86%), clean coffee yield per tree (24.03%), number of secondary branches per tree (22.34%), height up to first primary branch (20%) and hundred bean weight (20%). High heritability was coupled with high genetic advance as percent of mean for characters such as hundred bean weight and height up to first primary branch. The high heritability with high genetic advance as percent of mean observed for these characters is due to the lesser influence of environment in expression of the characters and additive gene effects. The present study indicated the presence of variability for some important morphological traits among the accessions. Therefore, the variability observed for yield, disease resistance and other important traits should be utilized to improve Gomma woreda coffee. However, since high morphological variation between accessions is not a guarantee for a high genetic variation, molecular and biochemical studies need to be considered as complementary to morphological variability. On the other hand, as most of the traits exhibited low GCV and/or low GAM, there is no opportunity to improve these traits using simple selection. Therefore, heterosis breeding should be applied to improve these traits.

In Ethiopia, the natural forests with the occurrence of wild Arabica coffee gene pools are under constant threats, largely due to anthropogenic activities. The study was conducted to compare the variability among the wild arabica coffee genotypes in biomass assimilation and allocation patterns under varying light and irrigation conditions at the Jimma Research Center, southwestern Ethiopia. The treatments included irradiance (moderate and full sunlight), irrigation (well watered and water stressed) regimes and twelve coffee genotypes of different geographical areas. One-year-old seedlings were used to record dry mass of leaves, main stem, primary branches and root growth. Each organ was separately oven-dried and total dry matter production and allocation patterns were measured and analyzed. The results depicted highly significant differences between the contrasting irradiance and irrigation regimes as well as among coffee genotypes. Significantly the lowest and highest stems dry mass values recorded for Berhane-Kontir and Harenna genotypes, respectively. Most accessions had relatively lower assimilations in shade as compared to full sun light conditions. Likewise, coffee seedlings significantly differed in root dry mass and root to shoot ratio, dry matter partitioning due to the main and combined treatment effects. Overall, total biomass assimilation and partitioning were higher for unshaded, water stressed and Harenna genotypes from the respective treatment groups. Conversely, leaf dry matter, leaf share was significantly high under moderate shade environments. The total dry matter share varied for the seedling growth parts (root = 22%, leaf = 35%, stem = 43% and whole shoot = 78%). The root growth followed the order of Harenna > Yayu > Bonga > Berhane-Kontir populations. The reverse was true for the leaf and whole-shoots, demonstrating the completion between above and below ground growth parts and thus the need to consider both dry matter assimilation and partitioning patterns in identifying desirable genotypes and optimum environments for future breeding program in Ethiopia

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