Safflower (Carthamus tinctorius L.) is a temperate plant grown in arid and semi-arid regions of the world, and is the most drought tolerant oilseed crop. The objective of this study was to evaluate the effect of genotype and plant density on growth, phenology and yield of safflower. Treatments included five safflower genotypes and six plant densities laid out in a randomised block design. Increasing plant density from 62,500 to 100,000 plants ha-1 significantly (P < 0.05) increased leaf area index (LAI), leaf area duration (LAD), total leaf chlorophyll content (Tchl) and net assimilation rate (NAR) at all phenological stages in both winter and summer. For all genotypes, the highest LAI, LAD, Tchl, NAR, total dry matter accumulation (TDM) and seed yield resulted at a plant density of 100,000 plants ha-1. Maximum LAI, LAD, NAR and Tchl were observed at 50% flowering, compared to other phenological stages in all genotypes and plant densities. In general, genotype ‘Sina’ at 100,000 plants ha-1 significantly (P < 0.05) had the highest LAI, LAD, Tchl, TDM and seed yield compared to other genotypes and plant densities in both summer and winter.

Safflower (Carthamus tinctorius L.) is a multipurpose oilseed crop that is tolerant to drought, saline, heat and cold conditions; and yields high quality edible seed oil. The objective of this study was to evaluate the effect of plant density and genotypes on oil content and fatty acid composition of safflower. A field experiment was conducted in the years 2015 and 2016, during winter and summer seasons. Treatments included five safflower genotypes and six plant densities. Genotype and plant density significantly interacted (P < 0.05) to influence oil content and fatty acid composition of safflower. Increasing plant density from 62,500 to 100,000 plants ha-1 significantly (P < 0.05) increased the oil concentration from 16 to 54%, depending on the interaction between genotype and plant density and genotype by environment (winter and summer seasons). However, as plant density increased from 100,000 to 200,000 plants ha-1, safflower oil content significantly (P < 0.05) decreased in all genotypes. The lowest and highest oil contents was produced by genotype ‘Gila’ planted at density 62,500 or 200,000; and ‘Sina’, ‘Pi 537 636’ at 100 000 or 125, 000 plants ha-1 in winter or summer, respectively. Fatty acid composition was significantly influenced by genotype and plant density interactions during the two growing seasons. The main fatty acids identified included linoleic, oleic, stearic and palmatic. There was a significant (P < 0.05) increase in linoleic acid content and a decrease in oleic, palmatic and stearic as plant density increased from 62,500 to 100,000 plants ha-1, depending on genotype or growing season. Genotype ‘Sina’ at 100,000 plants ha-1 produced the highest oil content and with high unsaturated fatty acid concentrations.