Allelopathic Effect of Eucalyptus globulus Labill. on Seed Germination and Seedling Growth of Highland Teff (Eragrostis tef (Zuccagni) Trotter)) and Barely (Hordeum vulgare L.)

The phenomenon of allelopathy, whereby a plant species chemically interferes with the germination, growth or development of other plant species has been known and documented for over 2000 years. Allelochemicals are secondary metabolites of plants, released into the environment through volatilization, leaching, root exudation and decomposition of residues. This study was aimed to examine the allelopathic effect of Eucalyptus globulus on seed germination and early growth of highland teff (Eragrostis tef) and barely (Hordeum vulgare L.) conducted at Kulumsa Agricultural Research Center. Fresh leaf, juvenile stems, root and mixtures of these aqueous extracts at 0%, 5%, 10%, 15%, 25% and 50% concentrations respectively were used to run the experiment under Laboratory condition. The employed research design was Complete Randomized Design with three replications and two factorials as: plant parts and concentrations. The quantitative data was collected, coded and then subjected to SAS Version 9.1 procedure following two ways ANOVA. The means were compared by using least significance difference test (LSD) at P<0.05 probability level. It was noted that aqueous extracts at a concentration of 10%, 15%, 25% and 50% had an inhibitory effect on both crops seed germination and seedling growth. The effect was found in much higher than the control treatment. The inhibitory effects were increased as the extract concentration increased and more pronounced in fresh leaf aqueous extract compared to the rest extract sources. This finding indicates allelochemials in the Eucalyptus globulus plant parts adversely affect seed germination and early seedling growth of teff and barely. The Phytotoxicity of Eucalyptus globulus fresh leaf aqueous extract showed the highest impact affecting early root growth of barely and shoot growth of teff under the highest level of concentration (50%) of the extracts.