Yield, Antioxidant Components, Oil Content, and Composition of Onion Seeds Are Influenced by Planting Time and Density

Abstract

Research was carried out on onion landrace (Ramata di Montoro) for seed production in southern Italy, with the aim to evaluate the effects on yield and quality of four bulb planting times in factorial combination with four densities, using a split plot design with three replicates. The number of flower stalks per plant, their height and diameter, and the inflorescence diameter decreased with the bulb planting delay and density increase. The highest plant leaf area and LAI (leaf area index), seed yield, number, and mean weight were recorded with the earliest planting time, with the lowest bulb density eliciting the highest plant leaf area but the lowest LAI and seed yield per hectare. The ratio between seeds and inflorescence weight, and seed germinability, decreased with the planting delay and density increase. Seed oil, protein, and antioxidant content (polyphenols and selenium) were highest with the last crop cycle. The polyunsaturated fatty acids, predominant in oil, increased with planting time delay, whereas the monounsaturated fatty acids decreased. Linoleic, oleic, and palmitic acid prevailed among polyunsaturated, monounsaturated, and saturated fatty acids, respectively. Planting from 20 December to 10 January with 3.3 cold-stored bulbs per m2 was the most effective combination in terms of seed yield per hectare, whereas seed oil content and quality were the best, with the last crop cycle starting on 21 February, independent of bulb density.

Seeds as Potential Sources of Phenolic Compounds and Minerals for the Indian Population

“…In fact, more than 20 bioactive compounds with phenol structure have been reported for this botanical species [ 34 ]. The total polyphenols content was also similar for other species, such as Allium cepa seeds, reported in the range of 200–400 mg/100 g by other authors [ 35 , 36 ]. In this respect, Žilic et al [ 37 ] demonstrated that polyphenols play an important role in sunflower seed oil, by protecting it from oxidation during storage.…”

Oil content, fatty acid composition and biodiesel properties among natural provenances of Siberian apricot (Prunus sibirica L.) from China

“…(2015). The oil content of Siberian apricot is higher than sunflower ( Helianthus annuus L.; 19.7%–34.6%; Seiler et al., 2018), Barbados nut ( Jatropha curcas L.; 11.68%–42.08%; Kaushik & Bhardwaj, 2013), tree‐of‐heaven ( Ailanthus altissima Swingle; 38%; Hoseini et al., 2018), onion ( Allium cepa L.; 22%–26%; Amalfitano et al., 2019), purpleblow maple (Acer truncatum Bunge; 17.81%–36.56%; Qiao et al., 2018) and tree peony ( Paeonia ostii T.; 18.30%–24.04%; Liu et al., 2019). This means that Siberian apricot is the most potential biofuel material, and it is economical to obtain oil by processing Siberian apricot seeds.…”

Recent Advances in Bioactive Compounds, Health Functions, and Safety Concerns of Onion (Allium cepa L.)

“…The content of phenolics in the onion bulb and its antioxidant property were increased with the application of mycorrhizal inocula, humic acids, and elevated atmospheric CO 2 (137). Planting time and density were also found to influence the antioxidant components of onion seeds (138). Besides, stored atmosphere conditions could affect the quality and bioaccessibility of total phenolics and antioxidant activity of the floral stem of the second-year onion resprout (139).…”