Sixteen faba bean genotypes were evaluated in 13 environments in Ethiopia during the main cropping season for three years (2009)(2010)(2011). The objectives of the study were to evaluate the yield stability of the genotypes and the relative importance of different stability parameters for improving selection in faba bean. The study was conducted using a randomized complete block design with four replications. G × E interaction and yield stability were estimated using 17 different stability parameters. Pooled analysis of variance for grain yield showed that the main effects of both genotypes and environments, and the interaction effect, were highly significant (P ≤ 0.001) and (P ≤ 0.01), respectively. The environment main effect accounted for 89.27% of the total yield variation, whereas genotype and G × E interaction effects accounted for 2.12% and 3.31%, respectively.Genotypic superiority index (P i ) and FT3 were found to be very informative for selecting both high-yielding and stable faba bean genotypes. Twelve of the 17 stability parameters,, W i , σ i 2 , EV, P 59 , and ASV, were influenced simultaneously by both yield and stability. They should accordingly be used as complementary criteria to select genotypes with high yield and stability. Although none of the varieties showed consistently superior performance across all environments, the genotype EK 01024-1-2 ranked in the top third of the test entries in 61.5% of the test environments and was identified as the most stable genotype, with type I stability. EK 01024-1-2 also showed a 17.0% seed size advantage over the standard varieties and was released as a new variety in 2013 for wide production and named "Gora". Different stability parameters explained genotypic performance differently, irrespective of yield performance. It was accordingly concluded that assessment of G × E interaction and yield stability should not be based on a single or a few stability parameters but rather on a combination of stability parameters.

A field experiment was conducted in 2001 at Holetta and Kulumsa, Ethiopia, to study genetic diversity in Ethiopian faba bean (Vicia faba L.) landraces. One hundred sixty random germplasm accessions were grown in an alpha lattice design with two replications. Data on 12 traits were collected and analyzed. Significant differences were observed among the accessions for most of the traits (except number of pods/podding nodes) at each location even though differences pooled over location were mostly non-significant. Cluster analysis distinguished seven diversity classes of different sizes. Accessions from the northern half of the country (North and South Wello, North Gonder and North Shewa) were closely related while those from the southern part of the country (Arsi) were highly diverse. Cumulative effects of a number of characters dictated differentiation of the accessions into clusters. Some overlapping were encountered between accessions from the northern and those from the southern parts of the country. The study revealed that accessions from different regions might have similar genetic background and those from the same origin might also have different genetic background. Therefore, geographic diversity should not necessarily be used as an index of genetic diversity and parental selection should be based on a systematic study of genetic diversity in a specific population. Genetic distances between most of the clusters were significant that crosses between parents selected out of them are expected to generate desirable progenies. Future germplasm collection, conservation and utilization strategies should put more focus not only on inter-regional diversity in the country as a whole but also on intra-regional diversity in Arsi.

An experiment was conducted in 2001 at Holetta and Kulumsa, Ethiopia, to study the extent and pattern of genetic diversity in Ethiopian field pea (Pisum sativum L.) landraces. One hundred forty-eight germplasm accessions were grown in an alpha lattice design with 2 replications. Data on 12 traits were collected and analyzed. Differences among the accessions were significant for most of the traits (except number of seeds/ pod) at each location even though differences pooled over location were mostly non-significant. The accessions were grouped into five clusters of different sizes. Accessions from the southern part of the country (Arsi) distributed overall clusters while those from the northern half (North and South Wello, North Gonder and North Shewa) fell into clusters C 1 to C 3 . Cumulative effects of a number of characters dictated differentiation of the accessions into clusters. There was no definite relationship between geographic diversity and genetic diversity as overlapping was encountered in clustering pattern among accessions from different parts of the country. Accessions from different regions might have similar genetic background and those from the same origin might also have different genetic background. Therefore, geographic diversity should not necessarily be used as an index of genetic diversity and parental selection should be based on a systematic study of genetic diversity in a specific population. Genetic distances among most of the clusters were significant that crosses between parents selected out of them are expected to generate desirable genetic recombination. Selection should also consider the special advantages of each cluster and each accession within a cluster. Future germplasm collection, conservation and breeding efforts should focus not only on inter-regional diversity but also on intra-regional diversity.

Faba bean is the leading in area coverage and total production of pulses in Ethiopia. However, soil acidity becomes the major production limiting factor of faba bean in the highlands of Ethiopia. Information on genetic variability and heritability of faba bean genotypes on different traits under soil acidity stress is scanty. Thus, this study was conducted to estimate genetic variability of faba bean genotypes on grain yield and related traits at soil of pH 4.66, 4.96 and 4.49 at Holetta, Watebecha Minjaro and Jeldu, respectively, during 2017 main cropping season. The experiment comprised 50 faba bean genotypes arranged in randomized complete block design with three replications. Data were collected on grain yield (g/5plants) and some other agronomic traits: days to 50% flowering, days to 90% maturity, grain filling period, plant height (cm), number of poding nodes/plant, number of pods/ poding node, number of pods/plant, chocolate spot disease (%) and 100-seeds weight (g). Analysis of variance for traits studied showed significant differences among genotypes, locations and their interaction (P ≤ 0.01) for all traits except number of pods/poding node for the interaction. Computed genotypic (GCV) and phenotypic coefficient of variation (PCV) values were ranged from 1.08-23.05 and 1.20-23.26%, respectively, whereas heritability (H 2) and genetic advance as percent of the mean (GAM) ranged from 24.63-98.22% and 2.0-47.13%, respectively. The highest values for all components were recorded for 100-seeds weight while lowest values except for H 2 computed for days to 90% maturity. The observed PCV and GCV values were high for 100-seed weight and moderate for grain yield, number of poding node/plant and pod/plant. The values of PCV were higher than GCV for all traits. Hence, the high variation between PCV and GCV (6.78) for chocolate spot was due to environmental stress (soil acidity) besides the genetic constitution of tested genotypes. High H 2 and GAM were observed for 100-seeds weight, number of pod/plant and poding node/plant. Traits with high H 2 indicated that selection based on mean would be successful in improving the traits. Therefore, selection based on phenotypic performance of genotypes would be effective to improve traits that have high GAM coupled with high H 2 estimates.

Abstract:Ethiopia is considered an important center of secondary diversity for both faba bean (Vicia faba L.) and field pea (Pisum sativum L.). However, areas of eco-geographic distribution and the microcenter of genetic diversity are not well known. Two separate trials consisting of 160 faba bean and 148 field pea accessions were conducted at Holetta and Kulumsa in 2001. Simple and alpha-lattice designs with 2 replications were used for faba bean and field pea, respectively. Cluster analysis grouped faba bean accessions into eight and field pea into five different classes. Mahalanobis's D 2 analyses showed significant genetic distances between most of the clusters in both crops. Accessions from the northern parts of the country showed tendencies of being grouped together, indicating that their genetic background may be related. Accessions from the southern parts of the country were distributed over most of the clusters showing more genetic diversity compared to those from the northern parts. This indicates that the distribution of genetic diversity among accessions is not uniform across different eco-geographical regions in Ethiopia and the microcenter of genetic diversity for both crops may be located in the southern part of the country. The existence of more genetic diversity in one region compared to the other could be due to differences in the level of variability among the original introductions to different regions, the nature and degree of both human and natural selections after introduction, and effects of ecological and agricultural conditions as major forces of evolution. Future collection, conservation and utilization programs should focus on the southern part to safeguard and exploit the tremendous genetic diversity. However, a comprehensive study involving both morpho-agronomic traits and molecular markers would be needed for a more comprehensive conclusion.