Algal habitat-forming forests composed of fucalean brown seaweeds (Cystoseira, Ericaria, and Gongolaria) have severely declined along the Mediterranean coasts, endangering the maintenance of essential ecosystem services. Numerous factors determine the loss of these assemblages and operate at different spatial scales, which must be identified to plan conservation and restoration actions. To explore the critical stressors (natural and anthropogenic) that may cause habitat degradation, we investigated (a) the patterns of variability of fucalean forests in percentage cover (abundance) at three spatial scales (location, forest, transect) by visual estimates and or photographic sampling to identify relevant spatial scales of variation, (b) the correlation between semi-quantitative anthropogenic stressors, individually or cumulatively (MA-LUSI index), including natural stressors (confinement, sea urchin grazing), and percentage cover of functional groups (perennial, semi-perennial) at forest spatial scale. The results showed that impacts from mariculture and urbanization seem to be the main stressors affecting habitat-forming species. In particular, while mariculture, urbanization, and cumulative anthropogenic stress negatively correlated with the percentage cover of perennial fucalean species, the same stressors were positively correlated with the percentage cover of the semi-perennial Cystoseira compressa and C. compressa subsp. pustulata. Our results indicate that human impacts can determine spatial patterns in these fragmented and heterogeneous marine habitats, thus stressing the need of carefully considering scale-dependent ecological processes to support conservation and restoration.
Combining ability and gene action 6 half diallel crosses. Results revealed that ability mean squares were significant for all studied additive and nonadditive components in the predominance of additive gene effects for From the GCA effect, it was observed that combiner for all yield component ombining ability and gene action of a set of durum wheat characters were studied using 6 6 half diallel crosses. Results revealed that general (GCA) and specific (SCA) combining were significant for all studied traits, suggesting the importance of both additive and nonadditive components in the inheritance of these traits. Baker ratio indicate the predominance of additive gene effects for the majority of traits studied except grain yield.it was observed that none of the six parents was yield components. Among the fifteen crosses, Zenati-Bouteille/Flamengo x followed by Waha x Ofanto, Waha x Mexicali 75 and Ofanto x Guemgoum Rkhem the greatest positive SCA effect for grain yield. Days to heading index could be used as an indirect selection criterion for better grain yield.selecting early heading genotypes having high fertile tillers number could improve grain
This research was conducted to screen and analyse the variability within twenty F 3 populations of bread wheat (Triticum aestivum L.) generated by Line x Tester mating design.The results indicated the presence of sufficient variability within and between F 3 populations for the eight measured variables, which represent plant phenology, physiology, yield and yield components. Different populations have been identified to improve the measured variables separately. The number of spikes appeared to be the most important determinant of grain yield.PCA and cluster analyses indicated that the Acsad 1069 /El Wifak and Acsad 1135 /Hidhab, with a relatively high grain yield, aboveground biomass and 1000 grains weight, are the best F 3 populations to improve the productivity. However, Acsad 899 /Rmada and Acsad 1135 /Rmada populations were earlier and had a low number of spikes. These populations had also favorable genes for heat tolerance.
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ABSTRACTThis research was conducted to screen and analyse the variability within twenty F 3 populations of bread wheat (Triticum aestivum L.) generated by Line x Tester mating design.The results indicated the presence of sufficient variability within and between F 3 populations for the eight measured variables, which represent plant phenology, physiology, yield and yield components. Different populations have been identified to improve the measured variables separately. The number of spikes appeared to be the most important determinant of grain yield.PCA and cluster analyses indicated that the Acsad 1069 /El Wifak and Acsad 1135 /Hidhab, with a relatively high grain yield, aboveground biomass and 1000 grains weight, are the best F 3 populations to improve the productivity. However, Acsad 899 /Rmada and Acsad 1135 /Rmada populations were earlier and had a low number of spikes. These populations had also favorable genes for heat tolerance.
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