The effect of row spacing and weed density on growth indices of canola (Brassica napus) in competition with wild mustard (Sinapis arvensis)

Abstract
In order to evaluate the competitive ability of canola growth indices against wild mustard, field experiment was conducted in agricultural research station of Gorgan University in 2009-2010. The experiment was carried out as factorial in a Randomized Complete Block design with three replications. The experimental factors included canola row spacing at 3 levels (12, 24 and 36 cm) and wild mustard densities at 4 levels (0, 4, 8 and 16 plant per m2). Results showed that growth indices of canola (LAI, CGR, RGR and TDM) decreased in competition with wild mustard. Also, leaf area distribution around the canopy at the higher height in row spacing of 12 cm as compared to 24 and 36 cm. Results revealed, higher leaf area index and better vertical leaf area distribution of canola could be reduced wild mustard biomass, and could be more competitive ability in weed-infested conditions.
Key words: Vertical leaf area distribution, Crop growth rate, Leaf area index