Exogenous Application of Thiourea Improves the Growth, Seed Yield, and Seed Fatty Acid Profile in Late Sown Camelina

Oilseed production under semiarid conditions in Pakistan is under a threat of thermal stress at the early and later stages of the crop. This study was carried out to evaluate the effect of sulfhydryl thiourea on the performance and quality of late sown camelina. The study comprised of; (i) sowing time (ST): ST₁ = 10 November and ST₂ = 30 November; (ii) camelina genotypes: the Australian (611) and the Canadian (618); and (iii) thiourea applications (1 g L⁻¹): TU₀ = no application (control-no applications), TU₁ = water spray at the vegetative stage (positive control), TU₂ = thiourea spray at the vegetative stage (1 g L⁻¹), TU₃ = water spray at the reproductive stage (positive control), and TU₄ = thiourea spray at the reproductive stage (1 g L⁻¹). Sowing time, genotypes, and thiourea supplementation showed a significant effect on the parameters studied, including physiological attributes, seed yield, and quality parameters. Yield and yield attributes were negatively affected in the late sown crop due to a significant reduction in gas exchange and plant water status compared with an early sowing. Seed quality was also affected by late sowing as saturated fatty acids increased and unsaturated fatty acids reduced under late sown crops. However, thiourea supplementation significantly improved the gas exchange, seed yield, and oil content than the control treatment. Thiourea applications improved the concentration of unsaturated fatty acids (linoleic acid and linolenic acid) and decreased the concentration of saturated fatty acids (palmitic and stearic acid). However, thiourea applied at the reproductive stage was more effective in relation to seed yield and seed quality parameters compared to thiourea application at the vegetative stage. Oleic acid desaturation ratio was reduced due to late sowing time; however, linoleic acid desaturation ratios were increased in late sown camelina compared to an early sown crop. Among camelina genotypes, the Canadian camelina performed better in relation to physiological and yield attributes and seed quality parameters relative to the Australian camelina. Thiourea supplementation improved seed yield and seed quality by improving unsaturated fatty acids under different sowing times with more improvement in the Canadian camelina compared with the Australian genotypes.