Effects of row-spacing and plant density on seed yield and yield components of safflower cultivars under irrigated conditions

In order to evaluate the effect of row spacing and seed rate on yield and yield components of safflower cultivars, a field experiment was conducted in research field of Seed and Plant Improvement Institute, Karaj, in 2015-2016 and 2016-2017 cropping seasons. A factorial experiment based on a randomized complete block design with three replications was conducted in the field experiments. Factors of the experiment consisted of two row intervals of 30 and 60 cm, two plant distances of 40 and 60 plants per square meter, and three safflower cultivars namely Padideh, Golmehr and Goldasht. In this study, the simple effect of row spacing on yield and yield components, simple effect of density on yield, oil yield, and number of grain per boll, and the interaction effect of row spacing × plant density on number of grains per boll were significant. Also, three safflower cultivars had significant differences for plant height, grain yield and oil yield. The results of this study showed that the highest grain yield was obtained at 30 cm row spacing (2312 kgha-1) and density of 60 plants per square meter (2263 kgha-1). Also, Goldasht and Golmehr had the higher grain yield compared to Padideh. Thus, the best recommendation for planting pattern of safflower cultivars in moderately cold areas is row spacing of 30 cm (two rows on stack) and density of 60 plants per square meter.