واﻛﻨﺶ دو رﻗﻢ ﺑﺮﻧﺞ ( Oryza sativa ) به رﻗﺎﺑﺖ ﺑﺎ ﻋﻠﻒﻫﺮز ﺳﻮروف (Echinochloa crus-galli )

To study the response of two rice cultivars (Hashemi and Shiroodi) to competition with barnyardgrass, an experiment was conducted outdoors in plastic pots in Bandar Anzali, Iran, in 2012. The experiment was carried out as a randomized complete block design with a factorial treatment arrangement and three replicates. Factors were two rice cultivars (Hashemi and Shiroodi) and five rice:barnyardgrass ratios (8:0, 6:2, 4:4, 2:6 and 0:8). The results showed that grain yield, aboveground dry weight and root dry weight of shiroodi cultivar were significantly increased as rice:barnyardgrass ratio reduced from 8:0 to 2:6. in contrast, there were no significant differences for grain yield, aboveground dry weight and root dry weight between 8:0 and 6:2 rice:barnyardgrass ratios for Hashemi, but these traits were significantly increased with further reduction in rice:barnyardgrass ratio. This experiment indicated that rice cultivars had different response to barnyardgrass competition in terms of grain yield, aboveground dry weight and root dry weight.