Seed Yield and Its Related Traits Performance of Common Bean (Phaseolus vulgaris L.) Varieties in Dawro Zone, Southwest Ethiopia

Poor addressing of all potential areas and slow turnover of old cultivars for more than 15-30 years are serious bottlenecks limiting production and productivity of common bean in Ethiopia. Farmers in the study area, Dawro zone, had been cultivating common bean landraces for about five centuries and Red wolaita for about 30 years. Red wolaita is low seed yielding and poor in quality due to loss of its genetic identity because of mixing up with landraces, genetic drift, and natural out crossing. Hence, thirteen newly released common bean varieties reported for their higher seed yield potential and Red wolaita were evaluated at seven locations for seed yield and its related traits performance using RCBD design with three replications in Dawro zone, southwest Ethiopia, in the 2010 main cropping season to select higher seed yielding and broadly adapted varieties. Analysis of variance (ANOVA) and additive main effects and multiplicative interaction (AMMI) models were used to analyze the data. The analysis of variance revealed presence of highly significantly difference (P < 0.01) between varieties for seed yield and its related traits performance. Combined AMMI model analysis of variance partitioned the variability in seed yield performance of varieties with the largest effect of location (50.27%) followed by variety effect (28.81%) and then variety by location interaction (GLI) effect (20.92%) indicating highly significant complication of GLI in selecting high seed yielding and broadly adapted varieties with greater influence of location. AMMI 1 biplot analysis enabled identification of higher seed yielding and broadly adapted varieties, Zebra-90, GobeRasha, Roba-1, Nasir, and Omo-95.  Higher seed yielding varieties were earlier to flower, but latest to mature. Longer plant height, and higher number of primary branches per plant, pods per plant, and seeds per pod had better contributed to higher seed yield performance. Generally, since broadly adapted varieties were the winners with rank change within themselves at all locations and no variety had performed specifically well, Zebra-90, GobeRasha, Roba-1, Nasir, and Omo-95 were recommended for production in the Zone and now Nasir, which has similar seed color with the old and low seed yielding cultivar in the Zone, Red wolaita, has got wider acceptance and at  popular production in the Zone. Keywords: AMMI, Broad adaptation, Dawro Zone, GLI, Seed yield, Variety, Yield related trait

AMMI and GGE Models Analysis of Stability and GEI of Common Bean (Phaseolus vulgaris L.)Lines in Ethiopia

When genotypes were introduced into a new and diverse production environments, occurrence of significant GEI (genotype by environment interaction) complicates selection of stable genotypes. Therefore, fifteen small red common bean lines introduced from CIAT including one standard check (Nasir) were evaluated at five representative dry bean growing locations of Ethiopia for seed yield performance using 4x4 triple lattice design in the 2013 and 2014 main cropping seasons to estimate the magnitude of GEI effects and to identify broadly or specifically adapted lines.  Combined ANOVA, AMMI and GGE biplot models were used to interpret the data.  Both the main and interaction effects were highly significant (P < 0.01) and  Environment, Line, and GEI explained 81.91%, 15.5% and 2.2% of variation in treatment structure, respectively,  and indicated greater influence of location and importance of simultaneous consideration of mean performance and stability. IPCA1 and IPCA2 were highly significant (p < 0.01) and together contributed nearly 60% variation in the GEI sum of squares. AMMI 1, GGE ranking, and GGE comparison biplots enabled identification of broadly adapted lines. Lines, KG-71-1, KG-71-23, and KG-71-44 were selected  as broadly adapted lines. GGE biplot analysis suggested presence of four mega-environments and enabled identification of specifically adapted lines. However, the specific adaptability of lines was not repeated over years and thus, GEI couldn't be exploited and broadly adapted lines  were recommended for verification and release. Keywords: AMMI, GGE, Adaptability, GEI, Broad adaptation, Line, Environmen

Dynamic Properties of Stabilized Subgrade Clay Soil

Expansive soils are fine-grained soils that can undergo a significant volume change due to the variation of water content. A change in the water content of weak subgrade material under the roadway is a cause for the damage of the road pavement. During an earthquake, the soft clay will lose the small shear strength it possesses which causes cracks and movements of the road. In the present study, soil samples were collected from Banda, Uttar Pradesh, India. The study area is at risk for seismic damage due to Himalayan frontal fault earthquakes. The soils samples are highly expansive in nature and used in road subgrade. The clay soil is treated with Rice Husk Ash and Portland cement slag. Strain control cyclic triaxial tests were carried out on the stabilized clay for different amplitudes of shear strain at frequency of 0.5Hz and 100kPa effective confining pressure. The damping ratios increase with increase in amplitude of shear strain and vary from 7-9% to 14-19% for γ= 0.4%to 1% respectively. The shear modulus decreases with increase in amplitude of strain. The modulus of degradation index decreases at a very fast rate for the first 50 cycles

Clean Development Mechanisms (CDM) and Climate Smart Agriculture (CSA): Role and Implication for Sustainable Natural Resource Management: Ethiopian Context

Ethiopia has been identified as one of the most vulnerable countries to climate variability and change, and is frequently faced with climate-related hazards, commonly drought and floods. The variability of rain fall and the increasing temperature were a cause for frequent drought and famine, and putting disastrous impact on the livelihood of the peoples. At the national level, World Bank suggests that climate change may reduce Ethiopia’s GDP compared to a baseline scenario by 2-6% by 2015, and up to 10% by 2045. The most vulnerable sectors to climate variability and change in the country are agriculture, water and human health. To cope up the effects of climate change, adaptation and mitigation measures are being practicing in the country. At the higher level, the governments has signed and ratified all the Rio Conventions, namely the United Nations Framework Convention on Climate Change and its Protocol, the Bio-diversity Convention and the Conventions to Combat Desertification. Following these, the government has initiated the Climate-Resilient Green Economy both to adapt and mitigate climate change. There are also different adaptation measures undertaking by different peoples at different levels. Thus, the purpose of this paper is to present adaptation and mitigation measures undertaking throughout the country at different levels. Keywords: Climate change, CDM, CSA, adaptation, mitigation, CRGE DOI: 10.7176/CER/11-11-04 Publication date: December 31st 201

Performance Optimization of Piled Raft Foundations in Layered Soil under Uniform Vertical Loading Using Plaxis 3D

Piled raft foundations are composite foundations that combine piles and raft to support civil engineering structure and to reduce the settlement. The data were obtained from Addis Ababa, Ethiopia. In this study, the effects of raft thickness, number of piles, pile length, spacing of piles, and pile diameter on the response of piled-raft foundations were investigated using the finite element-based program Plaxis 3D for layered soils (medium to very stiff high plastic silty clay and medium to very dense silty sand soil) subjected to uniform vertical loading. The results showed that increasing the thickness of the raft from 0.7 m to 1.7 m reduced the differential settlement by 78.21% when there were 16 piles. However, the maximum settlement also increased by 2.81%. Increasing the number of piles from 4 to 16 reduced the maximum settlement by 22.09% for a pile spacing of 4D. Moreover, increasing the pile length from 9 m to 15 m contributed to a 19.49% reduction in the total settlement for a pile spacing of 5D. Therefore, the current study provides a useful framework for analyzing and designing large piled-raft foundations