Agronomy Science (Oct 2017)
Influence of nitrogen fertilization on the seed yield and the content and quality of fat in pot marigold (Calendula officinalis L.) cultivars
Abstract
Pot marigold seeds contain oil with a specific composition (presence of calendic acid); hence, they can be used as an alternative oil raw material. In 2011–2013, a field experiment was conducted to determine the effect of different nitrogen doses (0, 30, 60, 90, 120, 150 kg N∙ha-1) on the seed yield, oil content, and fatty acid composition in four pot marigold cultivars. Nitrogen fertilization exerted a positive effect on the number of flower heads and seed yield. However, the response of marigold cultivars to nitrogen doses applied varied, i.e. the yield of the ‘Tokaj’ and ‘Radio’ cultivars was significantly increased up to the dose of 60 kg N∙ha-1, whereas such an increase was noted in the ‘Orange King’ and ‘Persimmon Beauty’ cultivars at the dose of 90 kg N∙ha-1. Nitrogen fertilization modified the content of fat: the low nitrogen doses (30 kg N∙ha-1) did not influence the fat content in the seeds, whereas the increasing doses resulted in its gradual decline. The cultivars were characterised by significant differences in plant morphology, seed yield, and fat quality. During the three-year period, the highest seed and fat yields were determined for the ‘Orange King’ cultivar (1857.3 and 339.3 kg·ha-1, respectively) and the highest proportion of calendic acid in the oil (54.86%) was detected in the ‘Persimmon Beauty’ cultivar. The yield and quality of marigold oil depended on both nitrogen fertilization and the weather conditions prevailing during the growing seasons. The increase in the nitrogen doses was accompanied by an increase in the content of linoleic acid and a decrease in the level of oleic acid. The cooler and wetter growing season in 2011 turned out to promote the highest fat and calendic acid accumulation.
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