Interference Effects ofWild oat (Avena fatua L.) on Yield and Yield Components of Two Cultivars of Spring Barley in Different Density Levels

In order to study the effects and the interference of wild oat over two varieties of spring barley, a greenhouse experiment was conducted in Tabriz University. Experimental designe was complete randomized design with three replications based on factorial experiment. The treatments were four density of the barley including 2, 4, 6 and 8 plants per pot, four density of the wild oat including 2, 4, 6 and 8 plants per pot and two barley varieties (Joonob and Kavir). For all densities of barley and wild oat, one pot was considered as control (monoculture of barley and wild oat). The results indicated that, Jonob variety was superior than the Kavir. The wild oat interference decreased the number of seeds in the primary spike, biological seed yield per plant and one 1000 seeds weight in compare with control. The 6 and 8 densities of wild oat decreased number of tiller in barely in compare with control. The highest amount in whole attributes in barely related to 2:2 (Joonob barely: wild oat) and the lowest amount related to 8:8 (Kavir barely:wild oat). Reducing rate in 2, 4, 6 and 8 densities of wild oat in barely in compare with control in seed yield of barely was equal 48.04, 53.35, 65 and 70.39 percent. This results showed that with increasing of wild oat density whole attributes of barely reduced, while Kavir was more sensitive than Joonob against wild oat.