In order to investigate the effect of the amount plant density on yield, yield components and growth characteristics of spring type of forage canola in summer cultivation, this experiment was conducted in Ghazvin(Esmail Abad) at 2011- 2012. This experiment was done in split plot form and with a randomized complete block design with three replications. The main factor included five levels of plant density :( 100, 125, 150, 175 and 200 plant per m2). The sub factor included two varieties of spring type of Canola including RGS003 and SARIGOL. The impact of plant density (p≤0.01) on final dry forage was significant. The highest dry forage yield was obtained from applying 100 plants per m2 and RGS003 variety with the average of 7381(kg.h-1). The highest forage protein (%) was obtained from using 100(plant.m-2) and RGS003 variety with the average of 13.12(%) whereas the lowest forage protein (%) was approached from200(plant.m2) and SARIGOL variety with average of 11.06(%). The highest forage fat(%) was obtained from using 100(plant.m-2) with average of 2.44(%). The RGS003 variety with average of 2.192(%) compared to SARIGOL variety with the average of 1.580(%) produced more forage fat. The highest LAI was obtained from using 200(plant.m-2) with average of 18.04. Increasing or decreasing in plant density resulted to decreasing in LAI. The effect of plant density and cultivars were significant on crop growth rate (CGR), relative growth rate (RGR), net assimilation rate (NAR), specific leaf weight (SLA), leaf area ration (LAR) and leaf area index (LAI).
