Effect of spring planting date on morpho-physiological traits of safflower genotypes in Kermanshah, Iran

The current study was conducted to evaluate the effect of sowing date on morpho-physiological traits of safflower genotypes in spring planting. The experiment was carried out in split-plot base on randomized complete block design in three replications. Sowing dates of March 21, April 04 and 19 assigned in main plots and cultivars including Arak 2811, Esfahan landrace, Goldasht and Sina in sub plots. The traits of dry weight at vegetative, budding, and flowering stages, relative growth rate, plant height, branches number per plant, boll number per plant, seed number per boll, 100 seed weight, biological yield, seed yield and harvest index were measured. The effect of planting dates was significant on all studied traits but seed number per boll, 100 seed weight and harvest index. The sowing date of March 21 and April 04 had the highest the lowest yield, respectively. The Interaction of planting date in genotypes was significant for traits of dry weight at vegetative, budding and flowering stages, and relative growth rate. Sina and Arak 2811 cultivars had the highest and the lowest yield, respectively. The highest positive significant correlation was between biological and seed yield. Also, there was a negative significant correlation relative growth rate and seed yield, indicating the role of this physiological trait on safflower seed yield. Therefore, planting of Sina cultivar of safflower on March 21 is recommending in Kermanshah region climate condition.