Evaluation of physical and chemical characteristics of bean and cup quality of arabica coffee genotypes grown in Southern Ethiopia.

The study aimed to investigate physical characteristics, cup quality, and biochemical content variability among thirty South Ethiopian Arabica coffee genotypes over three locations. The results revealed the existence of statistically significant variation among genotype, location, and GEI effects for all studied traits. The overall coffee quality score for most of the tested genotypes in three locations was above 80 %. Therefore, in terms of quality, most of the tested genotypes can be used to produce specialty coffee in the study areas. A wider range of caffeine (0.52 % dwb to 1.53 % dwb) was recorded among the studied genotypes. Accordingly, the low caffeine contenting genotypes could be a promising candidate for the development of low caffeine varieties through selection and hybridization. Cluster analysis grouped genotypes into different clusters based on quality trait variation and similarity among genotypes. According to the PCA, caffeine content (0.35), chlorogenic acid (0.34), aromatic quality (0.31), trigonelline (0.29), acidity (0.28), astringency (0.28), color (0.27) in the first PCA, flavor (-0.48), and screen size (0.46) in the second PCA were the important variables contributing more to the variation, and these traits could be considered for effective parent selection in quality improvement programs. Genotype AW9648 achieved the highest score in overall quality attributes at all three locations and could be promoted as a promising candidate and best parent for hybridization in terms of quality. Hence, genotype by environment interaction was significant, the coffee quality improvement program should give due attention to incorporating genetic and environmental influences by using a multi-locational selection strategy.

Study on characters associations and path coefficient analysis for quantitative traits of amaranth genotypes from Ethiopia.

Selection based on yield alone may not be effective for yield improvement in plant breeding programs. Thus, in order to progress the genetic gains during selection, yield should be considered along with potential yield contributing traits. The objective of this study was to improve the genotype of amaranth and increase the effectiveness of selection in the program by identifying the correlation and path coefficients between yield and its relevant attributes. On 120 genotypes of amaranth planted during two growing seasons in 2020 and 2021, the study was carried out using an alpha lattice design with two replications. The results revealed significant positive phenotypic and genotypic associations on leaf yield, with leaf area, leaf breadth, branch number, leaf number, plant height at flowering, and grain yield all having positive direct effects. Similar strong positive phenotypic and genotypic relationships were found for grain yield and grain sink filling rates. Using path coefficient analysis, the direct and indirect effects of yield-related traits on yield were also determined. In addition to having a strong direct impact on grain output, the grain sink filling rates showed both phenotypic and genotypic evidence of substantial positive relationships with grain yield. It was further suggested that leaf yield in amaranth genotypes may increase through the indirect selection of plant height at maturity, leaf length, and terminal inflorescence lateral length, which showed such significant indirect influences, mostly through leaf area, days to maturity, and days to emergence, which displayed such strong indirect effects, primarily through plant height at flowering. This study consequently shows the need for traits with significant positive indirect impacts via leaf area to be considered indirect selection criteria for improving leaf yield in amaranth genotypes. The grain sink filling rate also significantly improved grain yield indirectly at both the phenotypic and genotypic levels, mainly via days to flowering and leaf yield. This demonstrated that selection that mainly targeted days to flowering, leaf yield, and grain sink filling rate would ultimately boost the grain yield in amaranth genotypes.

Multivariate analysis for yield and yield-related traits of amaranth genotypes from Ethiopia.

The genus Amaranthus is one of the few dicotyledonous, non-grass mesophytes that use specialized C4 annuals or short-lived perennials to produce significant amounts of edible small-seeded pseudo cereals. In this study, we characterized the genetic diversity of 120 genotypes of amaranths collected from diverse amaranth-growing regions of Ethiopia using multivariate analysis of yield and yield-related traits. The experiments were carried out at Hawassa University, in the years 2020 and 2021. The experimental design was set up using an alpha lattice design and replicated two times. The collected data were examined for 24 descriptors. Principal component analysis showed that the first six principal components with eigenvalues greater than one contributed 80.41% of the variability. However, the first two principal components explained 52.42% of the total variation. The highest contributing traits in the first component were days to flowering, basal stem diameter, plant height at flowering, plant height at maturity, auxiliary inflorescence length, number of branches, terminal inflorescence lateral length, days to maturity, terminal inflorescence stalk length, leaf number, leaf length, top lateral branch length. The traits with the greatest weight on the second component were leaf area, basal lateral branch length, leaf length, and leaf width, grain filling period, grain sinking filling rate, and grain yield. Therefore, selection based on these traits would be effective for yield improvement in amaranth genotypes. Additionally, the hierarchical clustering grouped all the genotypes into five clusters. The pairwise generalized squared distance (D2) among the five clusters based on Mahalanobis's D2 statistics revealed the maximum and highly significant genetic distance was observed between II and III (277.79), while the minimum inter-cluster distance observed between clusters I and II (39.50). The findings suggest that amaranth genotypes in Ethiopia have a lot of genetic variation, which might be used for future breeding and ought to be conserved.

Genetic diversity of Ethiopian durum wheat (T. turgidum subsp. durum) landraces under water stressed and non stressed conditions.

Ethiopia, being a major center of origin and diversity for durum wheat, possesses a highly variable genetic pool with diverse agroecological adaptations. Wheat landraces are an important source of genetic variation for breeding programs. This study was conducted to study the genotypic diversity of Ethiopian durum wheat genetic resources under two contrasting environments namely drought-stressed and non-stressed. It was carried out on 100 landraces and 4 local checks using an augmented design. Data were collected on 13 traits comprising yield and yield components, phenology, and canopy condition. The analysis of variance revealed significant differences between landraces for different traits with different sources of variation. Several landraces were found to outyield the checks at both environmental conditions. Intermediate to high estimates of the phenotypic coefficient of variation (PCV), genotypic coefficient of variation (GCV), heritability in a broad sense (h2b), and genetic advance in percent of the mean (GAPM) were observed for all the studied traits except for days to flowering at normal, thousands seed weight at stress, and days to maturity, leaf chlorophyll concentration measurement, and canopy temperature measurement at both conditions. The estimation of variability parameters showed that genotypic variation was higher than environmental variation for most traits. The number of tillers, spike length, kernel per spike, and grain yield indicated higher values for h2b and GAPM (74.42% and 20.86; 83.2% and 28.24; 70.79% and 28.0; and 89.54% and 74.71) at normal and (97.87% and 98.22; 71.27% and 28.51; 75.52% and 43.9; and 90.04% and 103.68) at the stressed condition, respectively. Spikelets per spike, kernel per spike, and thousands seed weight were positively correlated with grain yield. Grain yield exhibited a weak negative correlation with days to heading and days to maturity. Principal components analysis revealed that six traits were the major loadings on the first two principal components that describe 37.9% and 41.0% of the total morphological variance at normal and stressed conditions, respectively. Cluster analysis grouped the landraces into six clusters, with each cluster showing variation in performance for different traits under normal and stressed conditions. The intracluster distance was maximum in cluster I (D2 = 7.68) and (D2 = 8.19) at normal and stressed conditions respectively and the intercluster distance was found to be maximum between clusters I and IV (D2 = 11.02) and clusters I and II (D2 = 10.33) at normal and stressed conditions respectively. The presence of significant genetic variability among the evaluated durum wheat landraces suggests an opportunity for improvement of grain yield through the hybridization of genotypes from different clusters and subsequent selection. Genotypes with superior agronomic traits that outperform the best checks are identified as potential parents for yield improvement programs for moisture stress.

Genetic diversity and differentiation of cultivated amochi (Arisaema schimperianum Schott) in Ethiopia as revealed by AFLP markers.

Amochi (Arisaema schimperianum Schott) is an off-season crop plant in southern Ethiopia, grown during the dry season on residual moisture, for its edible tubers. It has gained importance as a "security crop" especially during the years of moisture stress and food shortage. Amochi is irritating in contact to the skin. Removal of this effect is an important question for breeding. As the first step, however we attempt to establish base line information of its breeding system and genetic variability using AFLPs. The extent of genetic differentiation among 11 populations (96 individuals) of amochi sampled along altitudinal gradients that varied from 1700 to 3200 m a.s.l. was investigated. The populations were classified in to three altitudinal groups: lowland (1700 to 2200 m a.s.l.), central-highland (2201 to 2600 m a.s.l.) and highland (2601 to 3200 m a.s.l.). Polymorphic loci (167) scored from four primer pair combinations, were used for principal component analysis (PCA), and analysis of molecular variance (AMOVA). Both PCA and unweighed pair group with arithmetic mean (UPGMA) clearly differentiated populations into their respective altitude groups, with large genetic distances. AMOVA analysis revealed 70.5%, 16.7% and 12.8% variability between altitude groups, between populations and within populations respectively. Average diversity indices within populations were also low. Since the largest proportion of variation is located between altitude groups, rather than within populations, we suggest future studies on the chemical composition, low irritation, and other desirable traits should consider populations from different altitude ranges.