The Allelopathic Interactions of Crops on Growth Characteristics of (Pigweed Amaranthus retroflexus L.), (Wild Oat Avena fatua L.) and Wild Barely (Hordeum spontaneum Koch.)

A greenhouse study was conducted in Agriculture department of Shiraz university in 2009 to examine the allelopathic interactions of wheat (Triticum aestivum L.), corn (Zea mays L.) and canola (Brassica napus L.) extract on seedling growth of wild oat(Avena fatua L.), wild barely (Hordeum spontaneum Koch.) and pigweed (Amaranthus retroflexu L.). The experiment was done in a completely randomized design with 3 factorial replications. The treatments included water extract of wheat, corn and canola as individual, binary and ternary mixtures at 50% and 100% which were made and their effects on the growth factors of weeds was investigated. The results showed the binary mixture of wheat and corn extracts with 50% and the same mixture at 100% concentrations have the inhibitoriest effects on dry weight and final height of pigweed. The individual wheat extract at 50% concentration had the inhibitoriest effect on wild oat dry weight. The binary mixture of wheat and canola extract at 50%concentration decreased wild oat leaf area. The binary mixture of corn and canola extraction at 50% concentration and the individual corn extract at 100% concentration decreased wild barely dry weight. The individual canola extract at 100% concentration has the most inhibiting effect on final height of pigweed. The ternary mixture of wheat, canola and corn at 50% concentration decreased the wild barely leaf area. The results showed the extract at 100% concentration compared with 50% had the inhibitoriest effect. Also, binary and ternary mixtures of extracts had inhibitory effects compared to individually extract.