Study the effect of density on allelopathic of wheat (Triticum aestivum L.) Niknejad cultivar and some weed species using equal-compartment-agar method

Equal-compartment-agar method was used for studying the effect of allelopathic interaction of wheat and some problematic weeds in wheat. This experiment was accomplished as factorial in complete randomized design with 3 replications in weed research department of Crop Protection Research Institute, Tehran, Iran during 2006. The treatments were Niknejad cultivar in 4 densities 0, 8, 16 and 24 seedlings in glass tube and wheat weed spices: rye, oat, field bindweed and hairy vetch. The results indicated that the length of weeds was affected by wheat exudates more than their dry weight and similarly, rootlet was affected more than hypocotyl. In general growth of monocot species was decreased by wheat more than that of dicot species. Except hypocotyl length and dry weight, the increase in wheat density added the inhibition on weeds. Weed species had significant effect only on wheat hypocoty length and dry weight. mean while, oat was shown to be the most inhibitor. Except seedling hypocotyl length and dry weight, treatment of 16 wheat seedling density, caused the increase in wheat growth and dry weight.