Papers by Alemayehu Dabessa
Himalayan Journal of Agriculture, Oct 10, 2020
Field Crops Research, 2004
The size and nature of the genotype (G) and genotype  environment (G  E) interaction effects fo... more The size and nature of the genotype (G) and genotype  environment (G  E) interaction effects for grain yield, its physiological determinants, and grain size exhibited by the Andean grain crop quinoa at low latitudes were examined in a multienvironment trial involving a diverse set of 24 cultivars tested in 14 sites under irrigation across three continents. These environments included a wide latitudinal (from 21830 0 N to 16821 0 S), altitudinal (from 5 to 3841 m a.s.l.) and temperature (average daily temperatures during crop cycle varied from 9 to 22.1 8C) range; while average daily photoperiods exhibited a smaller variation, from 11.2 to 12.8 h. The G  E interaction to G component of variance ratio was 4:1 and 1:1 for grain yield and grain size, respectively. Two-mode pattern analysis of the environment-standardised matrix of grain yield revealed four genotypic groups of different response pattern across environments. This clustering, which separates cultivars from mid-altitude valleys of the northern Andes, northern altiplano, southern altiplano and sea level, showed a close correspondence with adaptation groups previously proposed. The results of the genotype clustering can be used to choose genotypes of contrasting relative performance across environments for further studies aimed at assessing the opportunity to select for broad or specific adaptation. Classification of sites for grain yield grossly discriminated between cold highland sites, tropical valleys of moderate altitude, and warmer, low altitude sites. As expected from the size of the G  E interaction component, no single genotype group showed consistently superior grain yield across all environment groups. The G and G  E interaction effects observed for the duration of the crop cycle had a major influence on the average cultivar performance and on the form of G  E interactions observed for total above-ground biomass and grain yield. Although different environment types showed contrasting effects on the physiological attributes underlying grain yield variation among cultivars, it was observed that good average performance and broad adaptation could come from the combination of medium-late maturity and high harvest index. Correlation analysis revealed no association between the average cultivar responses for grain yield and grain size. Three-mode pattern analysis have
INTRODUCTION Gute -19 soybean [Glycine max (L.) Merr.] Variety designated by pedigree of PM 12-3.... more INTRODUCTION Gute -19 soybean [Glycine max (L.) Merr.] Variety designated by pedigree of PM 12-3. This variety was tested across multi-environments (locations and years). Results from multi-location yield trials revealed that PM 12-3 was found to be superior and stable in seed yield and quality traits than the commercial variety viz., PARC-3. In addition, PM-12-3 varieties are resistant to bacterial blight and bacterial pustule. Hence, PM 12-3 variety was released by Bako Agricultural Research Center for Western part of Oromia regional state and similar agro-ecological zones of western parts of Ethiopia.
Journal of Agricultural Biotechnology and Sustainable Development
Currently, inorganic nitrogen fertilizer becomes a serious threat to the environment and human he... more Currently, inorganic nitrogen fertilizer becomes a serious threat to the environment and human health. Thus, finding alternate source of nitrogen is a viable option in assuring sustainable agricultural system. Biological nitrogen fixation is a critical and key process in sustainable agricultural systems in tropical soils, which are frequently deficient in N and susceptible to leaching of plant nutrients. This process transforms atmospheric nitrogen to ammonia, nitrate and nitrogen dioxide. Several key abiotic and biotic factors limit legume productivity and biological nitrogen fixation in World agriculture, especially in sub-Saharan Africa. Within the soil, rhizobia frequently encounter various stresses that affect their growth, initial steps of symbiosis and capability of nitrogen fixation. Biotic and abiotic stresses impose a major threat to agriculture and symbiotic nitrogen fixation is dependent on host cultivar and rhizobia, but as well may be limited by pedoclimatic factors. The most common factors affecting biological nitrogen fixation and symbiosis activity in western parts of Ethiopia are soil acidity, quality of inoculants and low soil fertility. In most cases, the microsymbiont is the more affected partner, with plants growing on mineral N usually less sensitive to these stresses. Thus, it can be concluded that, particularly in a western part of Ethiopia, many studies should be focused on acidity related constraints on biological nitrogen fixation, screening of acid tolerant inoculants and low soil fertility improvements to enhance biological nitrogen fixation in smallholder farming system.
Nine groundnut varieties were tested across six environments in western Oromia, Ethiopia during 2... more Nine groundnut varieties were tested across six environments in western Oromia, Ethiopia during 2013 main cropping season to evaluate the performance of groundnut varieties for kernel yield and their stability across environments. The varieties were arranged in randomized complete block design (RCBD) with three replications. Pooled analysis of variance for kernel yield showed significant (p≤0.01) differences among the varieties, environments and the genotype by environment interaction (GxE). Additive main effect and multiplicative interactions (AMMI) analysis showed highly significant (p≤0.01) differences for varieties, environments and their interaction on kernel yield. Similarly, the first and the second interaction principal component axis (IPCA1 and IPCA 2) were highly significant (p≤0.01) and explained 41.32 and 7.2% of the total GxE sum of squares, respectively. The environment, genotype and genotype by environment interaction accounted 14.7, 24.1 and 53.3% variations, respectively. This indicated the existence of considerable amounts of deferential response among the varieties to changes in growing environments and the deferential discriminating ability of the test environments. Shulamith and Bulki varieties showed the smallest genotype selection index (GSI) values and had the highest kernel yield and stability showing that these varieties had general adaptation in the tested environments. In the genotype and genotype by environment (GGE) biplot analysis, IPCA1 and IPCA 2 explained 63.5% and 22.4%, respectively, of genotype by environment interaction and made a total of 85.9%. GGE biplot analysis also confirmed Bulki and Shulamith varieties showed better stability and thus ideal varieties recommended for production in the test environments and similar agroecologies.
Uploads
Papers by Alemayehu Dabessa