Effect of Different Periods of Weed Interference and Weed Control on Height, Yield and Yield Components of Common Bean

In order to evaluate the effect of different periods of weed interference and weed control on plant height, seed yield and yield components of common bean, an experiment was conducted at the Agricultural and Natural Resources Research Center of Hamadan, Iran, in 2011. The experiment was a randomized complete blocks design with 3 replications. Treatments included two groups of weed interference and weed control. In the first group, weeds competed with crops until 10, 20, 30, 40 and 50 days after plant emergence. The second group included weed control until the aforementioned periods. Furthermore, two treatments including full season weed-free and full season weed-infested were considered as control plots. Results showed that weed dry matter had an ascending trend in weed interference treatments, while, it showed a descending trend in weed-free treatments. As the weed competition was increased, plant height showed a decreasing trend during the growing season. Number of pods per plant and number of seeds per pod in the treatments had significant differences at 1% and 5% probability levels, respectively; but they had no significant effect on 100-seed weight. Grain yield was significantly affected by the treatments (P≤ 0.01). Increasing duration of weed interference reduced the grain yield. The lowest grain yield (1168.3 kg/ha) was observed in the weed-infested plots. In contrast, increasing duration of the weed control, increased the grain yield. Maximum seed yield (2869.1 kg/ha) was produced by weed-free control treatment.