Canola Quality and Fatty Acids Composition as Influenced by Delayed Cropping and Late Season Drought Stress

Abstract

To investigate the effects of drought stress and delayed planting on oil quality and fatty ‎acids composition of canola cultivars, a factorial split-plot test was conducted in a ‎randomized complete blocks design with three replications at Seed and Plant Improvement ‎Institute, Karaj, Iran for two years (‎2015-2017) ‎.Planting date at two levels of timely ‎planting (Oct. 27) and late planting (Nov. 27) and irrigation at two levels of normal ‎irrigation (control) and restricted irrigation from pod formation stage onwards were ‎considered the main factors. Canola cultivars including Kodiak, Traviata, Compass, ‎Diffusion, Mehr2, Elvise and Tassilo were the variables. The simple effects of planting date, ‎irrigation, and cultivar on all research parameters were significant. The interaction effect of ‎planting date × irrigation was significant on oil yield and oil content at the level of 5% and ‎in terms of linoleic and palmitic acids, and stomatal resistance, it was significant at the level ‎of 1%. The interaction effect of irrigation × cultivar was significant on palmitic acid, ‎glucosinolate and stomatal resistance at the level of 1%. Late season drought stress and late ‎planting dramatically reduced oil yield (58%), oil content (8%) and qualitative ‎characteristics of canola cultivars. Among the studied cultivars, Tassilo cultivar was ‎recommended for all conditions of this research with the seed yield (4407 kg ha-1), oil yield ‎‎(2007 kg ha-1), chlorophyll content (1.43 mg g-1fw), high oleic and linoleic fatty acids, as ‎well as low and standard erucic acid (0.41%) and glucosinolate (22.8 μmol g-1).‎