Impact of Cultivar, Harvest Date and Threshing Parameter Settings on Floret and Carthamidin Yield of Safflower

Abstract

The industrial need for safflower (Carthamus tinctorius L.) increased over the last decade due to its potential use as food colorant. Safflower is mainly cultivated in Asia for its use as floret. In Germany, an economically attractive cultivation for floret use would require a mechanization of harvest. In order to develop a mechanical harvesting system, field experiments were conducted at the experimental station Ihinger Hof of the University Hohenheim in 2017 and 2018. Safflower was harvested with a combine harvester to obtain the florets. Two safflower (i) cultivars were harvested with (ii) three threshing parameter settings on (iii) five harvest dates to evaluate threshed floret yield, dry matter and carthamidin content, and carthamidin yield. Results showed that the maximum threshed floret yield was achieved at the latest harvest date (784.78–1141.76 kg ha−1), while the highest carthamidin contents were observed depending on cultivar on the first two harvest dates (0.53–3.14%). The decisive and resulting amount of carthamidin yield reached its maximum with the Chinese cultivar and the threshing parameter setting P3 between the fourth and fifth harvest date in 2018 (19.05–19.36 kg ha−1). Highest dry matter contents were achieved at the last harvest date (62.67–77.77%). Individual capitula weight and carthamidin content decreased with later harvest dates. Further investigations should clarify whether the individual capitula weight and carthamidin content correlate with each other or are independent of the date of harvest. This could be a decisive criterion for the selection of cultivars for harvesting florets with a combine harvester. Reduced costs of machine harvesting compared to hand harvesting will make the cultivation of safflower for the food coloring industry in Germany more attractive in the future.