Growth, Yield, and Phosphorus Efficiency of Safflower Cultivars as Affected by Phosphorus Application in East Azarbaijan Province, Iran

Abstract

ABSTRACT Identifying the cultivars that efficiently take up and use soil phosphorus (P) can reduce the financial and environmental costs of using P fertilizers. To investigate the growth, yield, and P acquisition efficiency of different cultivars of safflower affected by P deficiency and P applications, this study was conducted as a randomized complete block design in factorial arrangement with three replications in the Tikmeh Dash research station in East Azerbaijan province, Iran in 2016–2017. The studied factors were P fertilization in five levels (0, 10, 20, 30, and 40 kg P ha-1 from Triple superphosphate (TSP)) and safflower cultivars (Padideh and Goldasht). The results showed that under the P deficiency condition, the grain yield of Padideh was about 17% greater than that of Goldasht (1544 vs 1319 kg ha-1). Padideh cultivar was superior to Goldasht in terms of oil percentage (43.2 vs. 40.9%). Grain yield correlated with straw yield (R2 = 0.526**), P concentration (R2 = 0.192**), and the number of fertile capsules (R2 = 0.51**). In general, it is concluded that P concentration in straw is an important factor for grain production in safflower. Although both cultivars showed the greatest benefit-cost ratio of grain and oil yield in the 10 kg ha-1 P treatment, the Padideh cultivar was the superior cultivar. For the conditions of about 7.2 mg kg-1 available Olsen P, the application of 10 kg ha-1 P (50 kg ha-1 TSP) for the Padideh cultivar can be economical.