Effect of plant density on the PAR extinction coefficient and yield of safflower cultivars

This experiment was conducted to evaluate effects of plant density on the light interception rate and yield of safflower cultivars by a factorial layout based on randomized complete block design with three replications in 2010. Several plant densities such as 15, 25 and 50 plants per m2 and Mexican, Padideh, Goldasht, Native Isfahan and Zenderoud cultivars set as experimental treatments. Results showed that effects of treatments on all traits related to light such as leaf area index , PAR extinction coefficient, and light interception in flowering stage were significant. The highest amount of leaf area index and light interception and lowest PAR extinction coefficient were related to 50 plants per m2 and Isfahan native cultivar. The effect of cultivar on yield was significant as well. Interaction of plant density and cultivar on seed yield was significant too. The greatest seed yield equal to 3611 kg/ha and 3405 kg/ha produced in 50 plants per m2 and Isfahan native cultivar, respectively. The highest amount of oil yield produced by interaction of 50 plants per m2 and Isfahan native cultivar. According to the results, 50 plants per m2 and Isfahan native cultivar can lead to produce highest seed and oil yield in the our experimental condition and same regions.