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A study was conducted at Northwestern Ethiopia, during 2010 main cropping season. Fifteen maize genotypes were evaluated at four locations that differ in soil type, altitude and mean annual rainfall. The experiment was laid out in a randomized complete block design with three replications. Stability parameters that are useful tools for identification of genotypes with specific and wide adaptations, and contrasting the role played by genotype, environment and G x E interaction in multilocational variety trials were considered and analyzed. The highly significant G x E interactions indicated that genotypes performance was inconsistent across testing locations and need to be tested in several locations in order to select stable genotypes. Jibat-851, Wonchi and BHQPY-545 exhibited high mean grain yield across environments and average responsiveness with high degree of stability indicating general adaptability and thus can be recommended for north western Amhara region and for areas with similar environments. The best genotype with respect to location Adet was Gibe-1 while Wonchi was the best genotype for Merawi area. Phb-3253 performed well at Motta, while Phb-30G19 and Jibat-851 performed well at Finoteselam. Therefore, these genotypes can be recommended according to their specific adaptation area.

Garlic (Allium sativum) has for centuries been valued by humans for food, culinary and medicinal purposes world over. The objective of this study was to investigate genetic variability among garlic accessions for yield, yield related and phenology traits in Ethiopia. A field study was conducted at the DebreZeit Agricultural Research Center during 2012, using 49 garlic accessions from the highlands of North Shewa, East and West Arsi, Arsi, Bale and Sidama zones, which are among the major garlic producing areas in Ethiopia. The experiment was arranged in a 7x7 simple Lattice design, with two replications. Accession were highly significant (P < 0.01) for days to maturity, leaf number per plant, neck diameter, yield per plant, biological yield per plant, dry weight above ground, bulb dry weight, dry weight underground, clove number per bulb, and clove weight per bulb. Heritability estimates ranged from 82.48% for clove number, to 6.46% harvest index. High heritability, combined with high genetic advance (as per cent of mean) observed for mean clove number, yield per plant, biological yield per plant and clove weight per plant showed that these characters were controlled by additive gene effects. Thus phenotypic selection for these characters would likely be effective in variety selection and development. Bulb yield per plant had positive and highly significant genotypic and phenotypic correlations, with all characters, except plant height and harvest index. Path analysis at phenotypic level revealed that biological yield and bulb dry weight contributed major positive direct effects to bulb yield per plant. These traits showed positive and highly significant genotypic correlations with bulb yield except harvest index

Information on the combining ability and heterotic pattern of elite inbred lines is essential to maximize their use in hybrid maize development. This study was conducted to determine combining ability and heterotic pattern of locally developed maize inbred lines for grain yield and related traits. Seventeen inbred lines (10 female inbred lines and 7 tester inbred lines) were used to generate 70 single cross hybrids using line by tester crossing scheme. The resulting 70 cross progenies plus two standard checks arranged in 8×9 alpha lattice design replicated twice were planted at three mid-altitude subhumid testing sites in Ethiopia (Bako, Hawassa and Pawe) in 2011 main cropping season. The combined analysis of variance for yield and other related traits showed highly significant differences among genotypes, crosses, female inbred lines (General combining ability, GCA), tester inbred lines (GCA), line x tester (Specific combining ability, SCA); and the interactions of these source of variation with the environment for all traits studied except for ear aspect (EA) and grain yield (GY) in female inbred lines (GCA), EA in inbred line testers (GCA) and for days to anthesis (AD) in line x tester (SCA) x environment. The significance of both GCA (lines and testers) and SCA of LxT for AD, days to silking (DS), plant height (PH), ear height (EH), EA and GY showed that both additive and non-additive gene actions are important in controlling these traits. Furthermore, the proportion of GCA sum of squares were greater than the SCA sum of squares for AD, DS, PH, EH, and EA indicating the predominance of additive gene actions in controlling these traits. For GY, the ratio of GCA to SCA sum of squares was near to unity indicating both additive and non-additive gene actions were equally important. This study identified inbred lines that can make good cross combination for more than one trait. L1 was found to be good combiner for lower values of AD, DS, PH and EH indicating that this line could be used in improving maize for earliness and short stature. L4 was ideal parent for reducing AD and DS. L3 was found to be good combiner for GY and other related traits. In addition, lines were grouped into heterotic group A, B or AB based on SCA. Based on its per se performance and combining ability, L3 was proposed to be used as a tester in heterotic group B. This study also validated T5 remain to be used as a tester in heterotic group A. Based on the SCA of crosses, heterosis and per se performance of the parents, five best cross combinations were identified for possible release or for use as parents of three way hybrids. Further verification of the stability of the selected hybrids and the new proposed tester across more locations needs to be done.

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