Evaluation of Traits of Dry Bean (Phaseolurs vulgaris L.) under Weed Interference Conditions Using Boltzmann Model

Proper application of herbicides is a major concern in sustainable agriculture. This issue depends on our knowledge about weed plants، especially weed-crop competition. Therefore، In order to evaluate the effect of weed competition on some dry bean’s traits an experiment was conducted in 2011. The experiment was a randomized complete block design with 3 replications. Treatments included weed-infested and weed-free periods until 0، 10، 20، 30، 40 and 50 days after crop emergence. In order to evaluate trends of dry bean’s traits Boltzmann model was fitted to the data. Crop height had a descending trend in weed-infested treatments، while it had an ascending trend in weed-free plots. Increase in duration of weed interference reduced main stem’s node formation of the crop. Weed interference affected crop’s number of branches. This trait had a descending trend in weed-infested plots، while it was ascending in weed-free treatments. Weed competition influenced pods length as well، so that the minimum value of this trait (6. 56 cm) was observed in full season weed-free treatment. Regression analysis revealed a significant negative relationship between weed biomass accumulation and evaluated dry bean’s traits (height، number of nodes in main stem، number of branches and pods length) at 1% probability level. Therefore، weeds are able to restrict dry bean’s development and growth through constraining environmental essential resources in which consequently lead to a final yield reduction.