Grain Yield and Qualitative of Rapeseed Genotypes Change in Response to Exogenous Application of Salicylic Acid and Planting Density

A factorial split-plot experiment (2015–17) was carried out in a randomized complete block design with three replications at Karaj, Iran, to investigate the quantitative and qualitative responses of rapeseed genotypes to the exogenous application of salicylic acid at various plant densities. Three plant densities (40, 50, and 60 plants m⁻²) and two levels of application of salicylic acid (non-application and foliar application) were factorial in the main plots and six rapeseed genotypes (HW118, WPN6, HL3721, L14, Tassilo, and Natali) were in sub-plots. The number of siliques per plant, number of seeds per silique, seed yield, and oil yield improved when rapeseed genotypes treated with salicylic acid. The oil quality of studied genotypes enhanced due to a reduction in erucic acid and glucosinolate contents under the foliar application of salicylic acid. On average, by foliar application of salicylic acid, the highest seed and oil yields at the density of 40 plants m⁻² belonged to the L14 genotype, while the HW118 produced the maximum seed and oil yields at the densities of 50 and 60 plants m⁻². Generally, rapeseed genotypes should be cultivated at the density of 40 plant m⁻² and treated with foliar application of salicylic acid for achieving the maximum seed yield and oil quality.