Allelopathic effects of pigweed (Amaranthus retroflexus L.) organs on seed germination and seedling growth of canola (Brassica napus L.)

Greenhouse and laboratory studies were conducted to examine the allelopathic effects of water extracts of pigweed (Amaranthus retroflexu L.) leaf, stem, root and flower at different growth stages on canola seed germination and seedling growth. Water extracts of leaf, stem, root and flower as individually, binary, ternary and quadri mixtures at 0, 50 and 100% concentrations were made and their effects on the germination, shoot and root length, shoot and root dry matter of canola were investigated. Experiment was conducted in a completely randomized design in factorial arrangement with three replications. The results showed that quadric mixture of leaf, stem, root and flower exerted the most inhibitory effects on canola germination at 100% concentration in maturity stage. The most inhibitory effects on canola shoot length at 100% concentration in 2-4 leaf stage were observed in ternary mixture of leaf, stem and root extract. Quadric mixture of leaf, stem, root and flower extracts had the most inhibitory effects on canola root length at 100% concentration in maturity stage. The most inhibitory effects were observed in quadric mixture extract on canola shoot dry matter at 100% concentration in maturity stage. Ternary extract of leaf, stem and root extracts showed the most inhibitory effects on canola root dry matter at 100% concentration at 2-4 leaf stage.