Investigating the allelopathic potential of wild mustard (Sinapis arvensis) on germination components of wheat cultivars using Polyethylene Glycol 6000

In order to evaluate the allelopathic effects of shoot and root water extract of wild mustard (Sinapis arvensis) on germination properties and seedling growth of wheat cultivars, an experiment was conducted in the form of completely randomized design with three replications at the physiology laboratory of Golestan Agriculture and Natural Resources Research Center in Iran in 2011. Experimental treatments were components of water extract wild mustard shoot and root (0, 2.5, 5 and 7.5%) and wheat cultivars (Morvarid, Moghan, Tajan and Arta). Also, in order to separate the osmotic effects of different concentrations of wild mustard water extract from allelochemicals effects was used the polyethylene glycol 6000. The results showed that with increasing the concentration of shoot and root water extract of wild mustard, percentage and rate of germination, shoot and root length, shoot and root dry weight and seedling dry weight of different wheat cultivars decreased significantly. So that in the highest concentration, Moghan and Morvarid cultivars showed the least influence and Tajan and Arta cultivars showed the highest influence. Furthermore the different concentrations of polyethylene glycol had no effect on the traits mentioned above. This confirms that the osmotic potential of extracts had no influence in to intensify of allelochemicals effects. Fitting of three-parameter logistic model provided a successful estimation of the relationship between different levels of water extract and germination percentage. Generally, wild mustard shoot showed more inhibitory effect than the root.