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Volume 2 Number 11 November 2016

Genotype by Environment Interaction and Kernel Yield Stability of Groundnut (Arachis hypogaea L.) Varieties in Western Oromia, Ethiopia


Authors: Alemayehu Dabessa ; Birru Alemu ; Zerihun Abebe ; Dagnachew Lule
Pages: 113-120
Abstract
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 agro-ecologies.

Possibilities of Using Renewable Energy Sources for Covering All the Energy Needs of Hydroponic Greenhouses. A Case Study in Crete, Greece


Authors: John Vourdoubas
Pages: 107-112
Abstract
Hydroponic greenhouses consume large amounts of energy in order to cultivate the desired crops. Usually they consume fossil fuels for heat production and grid electricity for the operation of various electric devices. The aim of the current work is the investigation of the possibility of using renewable energy sources for covering all the energy needs of a hydroponic greenhouse in Crete, Greece. This could be achieved with the combined use of solid biomass and solar electricity. Solid biomass and solar-PV technology are mature, reliable, well-proven and cost-effective technologies. Solar irradiance and solid biomass, in the form of olive kernel wood, are abundant in Crete and they are extensively used for energy generation. For a hydroponic greenhouse in Crete, Greece with a covered area of 1,000 m2 and annual energy consumption of 245.5 KWh/m2, the installation cost of the abovementioned renewable energy systems has been estimated at   42,380€ and the CO2 emissions savings due to the use of solar energy and solid biomass at 104,725  kg CO2 /year. The size of the solar-PV system has been calculated at 17 KWp and the annual consumption of olive kernel wood at 66.87 tons/year. Therefore the use of renewable energies instead of fossil fuels in hydroponic greenhouses results in economic and environmental benefits and it should be promoted in order to increase sustainability in agriculture.