Role of foliar nutrition on the growth, yield, and fatty acid compositions of linseed (Linum usitatissimum L.)

Abstract

Linseed is considered as one of the oldest valuable plants, grown for oilseed and fiber crops. Despite the immense nutritional and industrial importance of linseed, no study has highlighted the effect of foliar nutrition and its day timing on the morpho-physiological characteristics. Therefore, a two-year study was conducted to assess the effect of foliar applying urea, boric acid, and salicylic acid, as well as the different day timing of foliar fertilization (at sunrise and sunset) on the quantitative and qualitative traits of linseed. This factorial experiment was performed based on a randomized complete block design with three replications in the research farm of Islamic Azad University, Miyaneh Branch, Iran. Based on the results, spraying urea at 9 and 15 g L−1 doses increased morpho-physiological attributes. However, the 3 and 6 g L−1 concentrations of boric acid resulted in maximizing mean yield and yield components. Additionally, the highest oil content and yield were respectively obtained by applying salicylic and boric acids. In general, foliar nutrition raised the level of saturated and unsaturated fatty acids compared to the control treatment. Further, a higher efficiency was achieved in case of enhancing quantitative and qualitative characteristics following foliar fertilization in the early morning (a.m.) compared to the sunset (p.m.). The foliar nutrition with urea, boric acid, and salicylic acid at moderate concentrations at the a.m. improved morpho-physiological traits, yield, and its components, as well as the qualitative characteristics of seed oil in terms of unsaturated fatty acids.