Five weeds (Echnichloacolonum, Cyperusrotundus, Xanthium pungenswallr, Solanum nigrumand Echinochloa crus galli) were tested for allelopathiceffect onPortulaceaoleracea L.and SetariaglaucaL. Beauv. in faculty of Agriculture, Alexandria University. Different concentrations (2.5, 5, 10, 20, 30 and 50%) from the stock solution of leaf extract were used to evaluate its effect on germination, shoot and root length as well as vigour index. The results showed that low concentrationsdid not affect

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... d parameters but higher concentrations specially 30 and 50% caused significant reduction in all these parameters.Allelopathic effect of these weeds was observed especially in the case of Xanthiumpungens, Echnichloacolonum on Portulaceaoleracea and Echnichloacolonum, Cyperusrotundus on Setariaglauca.