Safflower genotypes affected by nitrogen fertilization in subtropical conditions

Abstract

Nitrogen fertilization is one of the main management systems that affects safflower (Carthamus tinctorius) production. However, the response of safflower to nitrogen fertilization may vary depending on the genotype and growing conditions. The objective of this study was to evaluate the influence of nitrogen fertilization on yield components, oil content, and protein content of safflower genotypes in subtropical conditions. Two experiments were performed to evaluate the effect of nitrogen fertilization (0 and 160 kg ha–1) on six safflower genotypes. The experiment was designed in randomized blocks, in a 2 × 6 factorial design, with six repetitions. The height of the plants, yield, and oil and protein contents were determined 170 and 160 days after emergence in 2017 and 2018, respectively. The oil content and protein content of safflower genotypes were affected by nitrogen fertilization, but this effect varied depending on the genotype. Genotype 4 dominated with a grain yield of 1088 kg ha–1 and an oil yield of 215 kg ha–1. Nitrogen fertilization increased the grain yield, oil content, and protein content; thus, it is appropriate for the cultivation of safflower off-season in autumn-winter in subtropical conditions. Safflower genotype 4 could be a promising oilseed crop for southern Brazil when fertilized with 100 kg ha–1 of N.