Growth analysis of four safflower cultivars at different plant arrangement in dryland condition

In order to study the effects of three plant arrangements (Rectangle 40*40, Square20*20 and diamond 20*20) on growth of safflower, a field experiment was conducted in the experimental farm of University of Agricultural and Natural Resources in Gorgan, Iran, using the line NO10, Darab295, Arak2811 and Zarghan cultivars. The results of the growth analysis revealed that the trend of changes with GDD in the TDM, CGR, RGR, LAI and NAR was similar for the all plant arrangements and under study cultivars. For example, the LAI increased, but subsequently decreased with increasing GDD in the all treatments. The cultivar of Arak2811 possessed higher TDM, CGR, but lower NAR when compared with the other cultivars. The RGR in the rectangle arrangement was lower than in the other two arrangements. After about 900 GDD, the values of the NAR for the rectangle arrangement were to lowest. It was found that the seed yield was under the influence of plant arrangement and the cultivars.Araak2811, significantly, had the highest seed yield (3746 kg/h). Plant arrangement of equal distances between and within plant (rectangle and square) had the highest seed yield.