Genotypic and environmental variability of tocopherols and phytosterols in linseed (<i>Linum usitatissimum</i> L.) oil

Linseed, Linum usitatissimum L., oil is highly valued for its nutritional and industrial properties, which is due to its unique profile in fatty acids and of minor components such as tocopherols and phytosterols. In this study, we investigated the effects of genotype, growing year, and location on the content and composition of these compounds in L. usitatissimum oil, with a focus on understanding their variability under field conditions. Ten genotypes were cultivated over three growing seasons (2013–2015) in one southern (Lavaur) and two northern (Airaines and Poix-de-Picardie) locations in France. Oil was extracted using a modified protocol and analyzed via high-performance liquid chromatography for tocopherols and gas chromatography-mass spectrometry for phytosterols. Our results revealed a mean total tocopherol content of 403.7 mg/kg oil, with γ −tocopherol as the dominant isoform (397.4 mg/kg oil), and a mean total phytosterol content of 396.7 mg/100 g oil. Notably, genotype accounted for 49% of tocopherol variability, whereas environmental factors, especially location and year, contributed significantly to phytosterol variation (up to 44% variance). The adverse effects of the hotter, drier 2015 season on both compound classes underscore the impact of abiotic stress on oil quality. These findings provide a framework for breeding programs aimed at optimizing L. usitatissimum oil for both nutritional enhancement and industrial applications.