Effect of planting date and plant densities on light extinction coefficient, light interception and grain yield of safflower )Carthamus tinctorius L.(

In order to determine the effect of planting date and plant densities on light extinction coefficient, light interception and grain yield, this research was conducted in Jovain-Sabsevar in Season (2004-2005). The experimental design was a split _ plot based on randomized compelet block with three replications. The main plots were planting dates (Sep16,Oct7 and Oct27). Sub plots were plant densities (6,8,10,13,20 and 40 plant.m-2). The results presented that planting date had no significant effect on LAI,K,LI. But effect of planting date on number of capitul per plant, number of grain per capitul , grain yield per plant and grain yield (ton/ ha) were significant. The largest number of capitul per plant, number of grains per capitual, grains yield per plant, grain yield (ton/ ha) were obtained in 3th planting (Oct27). The effect of plant population on plant height, the height of first branch from the ground, LAI,K,LI, number of capitul per plant, number of grains per capitul, grain yield per plant and grain yield (ton/ ha) were significant. The results showed that the largest plant height, the height of first branch from ground , LAI,K,LI and grain yield (ton/ ha) were obtained in 20 and 40 plant per m2. Hence, the largest number of branch, number of capitul per plant, number of grain per capitul and grain yield per plant obtained in 6 and 8 plant per m2. But, both factors had no effect on 1000 grains weight. Plant densities had positive and significant correlation with grain yield (ton/ ha) , LAI , K and LI. Although plant population had negative and significant correlation with number of capitul per plant , number grain per capitul and grain yield per plant. So , LAI , LI correlation's with of grains yield (ton/ ha) was positive and significant. These factors showed linear relitionship with grain yield (ton/ ha). In this investigation , LAI and LI raised with plant population increment simultaneously. Maximum light interception obtained in 40 plant per m2 (LI=92%). however , optimum light interception (LI=95%) had not obtained.