Canola quality and fatty acids composition as influenced by delayed cropping and late season drought stress

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 on wards 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, with considering all conditions of this research, the Tassilo cultivar having 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). was recommended as a favorable cultivar for planting in temperate cold regions with arid and semi-arid climates.