The yield of 186 F 4 barley breeding lines, under stress and non-stress conditions, utilizing four stress indices: S (stress susceptibility index); P (yield deviation between genotype and best genotype in given environment); b (regression coefficient) and PCA (principal component analysis) scores, was investigated in an experiment carried out at the Agricultural Research Station of the Field Crop Institute of Sétif (Algeria). The results indicated significant differences between lines, with a grain yield mean ranging from 127.3 to 1246.6 g m -2 over the four cropping seasons and a genotype 9 environment variance component 1.83 higher than the genotypic variance component. S index identified divergent plant material under stressed and unstressed environments. Yield differential between lines with high and low S index was large, limiting the use of the S index to compromise between high yield and adaptability. Lines with low S values are high yielding under stress but are less responsive when growing conditions improve. Low P index identified lines with high yield in the unstressed environment and poor yield under stress conditions, while high P identified lines performing poorly in both environments, suggesting that P index was able to integrate both yield potential and yield stability. Lines with a slope b \ 1 showed similar grain yield as those with high P or low S values. Lines with of slope b = 1 have average yield, and as such combine average yield, adaptability and stress resistance. Because of their close mutual relationships, the indices were represented by the first principal component of the PCA, suggesting that PC (principal component) scores would be more appropriate to integrate yield potential and adaptation to variable environments.
Our objective is to study interaction between physical and chemical properties of soils and their earthworm community characteristics in different areas irrigated by wastewaters and well waters. The fields have different topography and agricultural practices conditions and are located in two regions of Batna department (Eastern Algeria). Both regions are characterized by a semiarid climate with cold winters and Calcisol soils. Nine fields were subject of this study. Three of these fields are located in Ouled Si Slimane region whose irrigation is effectuated by natural waters of Kochbi effluent. The other six fields are located at edges of Wed El Gourzi, effluent from Batna city, and partially treated through water treatment station. The best rates of water saturation and infiltration as well as abundance of earthworms were recorded at sites characterized by irrigation with wastewaters downstream of El Gourzi effluent. PCA characterizes two major groups: a group of hydrodynamic infiltration parameters and structural index stability of soil, explained by fields irrigated with wastewaters downstream of El Gourzi effluent. This group includes chemical characteristics: pH and electric conductivity. The second group is the characteristics of earthworms and includes organic matter content, active limestone levels, and Shannon Biodiversity Index.
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