evaluation of growth indices and estimation seed yield loss threshold of canola in response to various densities of crop and wild mustard

abstract in order to study the effect of various densities of wild mustard (sinapis arvensis l.) on growth indices of canola (brassica napus l.) in climate of molathani, ahvaz, an experiment was conducted in the experimental field of ramin agricultural and natural resources university, in 2006-2007. the split-plot set of treatments was arranged within randomized complete block design with four replications. treatments included of wild mustard at five levels (0, 7, 14, 21 and 35 plants m2) and canola at three densities (60, 80 and 100 plants m2). the results showed that the increase in mustard density rates lead to decreasing total dry matter, leaf area index, crop growth rate, relative growth rate and mean pod dry matter in three canola densities (60, 80 and 100 plants m2). somewhat the lowest growth indices was obtained in 35 plants mustard (that is the highest mustard density). in addition damage rate of mustard decreased canola seed yield for 7, 14, 21 and 35 plants mustard up to 61, 71, 76 and 91%, respectively.