Manganese and zinc effect on yield, fatty acid ratio, and maternal seeds germination of canola cultivars upon late-season drought stress

Abstract

To mitigate the effects of drought stress on fatty acid compositions and seed germination, various hypothesis have been studied by researchers. In this study, the field experiments were conducted in two cropping seasons (2020–2021) to investigate the effect of micronutrients on some characteristics of canola cultivars under late-season drought stress conditions. The experiments were arranged in a factorial split-plot design with three replications. The main factors included irrigation regimes (regular irrigation and irrigation interruption at the flowering stage) and foliar applications of Zn and Mn after rosette stage (F1: none application, F2: ZnSO4, F3: MnSO4, and F4: ZnSO4+MnSO4). The third factor included three cultivars, including Nima, R15 and KS7, as subfactor. Limited irrigation at flowering stage reduced length of seedling (25% and 17%), weight of seedling (30% and 14%), and seed yield (42% and 29) in first and second year, respectively. Irrigation withholding at flowering stage reduced seed yield by 37, 27, and 42% in R15, Nima and KS7 cultivars, respectively. Based on the current experimental data, irrigation withholding at flowering stage caused severe stress to the plants, especially those with long-term growth periods such as R15 and KS7. By contrast, the minimum yield loss was obtained from Nima cultivar, an early mature cultivar. Overall, it is recommended R15 cultivar for normal irrigation and Nima cultivar for a drought environment when considered the acceptable seed yield in new plants. In general, it is suggested that a suitable performance of canola seeds is achieved by foliar application of manganese and zinc.