Changes in oil and fatty acid composition of developing seeds of taramira (Eruca Sativa mill.) as influenced by sulphur and nitrogen nutrition

Randomized field experiments were conducted to study the interactive effect of sulphur (S) and nitrogen (N) on oil, protein, sugar and fatty acid composition in developing seeds of taramira (Eruca sativa Mill.). Two combinations of S and N (in kg ha⁻¹): S₀ + N₁₀₀ (−S+N) and S₄₀ + N₁₀₀ (+S+N) were used. In +S+N treatments, S was applied either as a single basal dose (T₂) or in two (T₃) or three splits (T₄). A rapid increase in total oil content commenced at 20 days after flowering (DAF) and continued to 40 DAF; the dry matter however, continued to accumulate until maturity. A gradual rise was found thereafter and finally the oil accumulated as storage oil. Combined application of S and N resulted in increased oil accumulation in the seeds right from the initial stage. The maximum increase was observed, when S and N were applied in three splits. There was a strong positive correlation between S and oil content in the seeds. Soluble protein content increased from 10 to 30 DAF, followed by a decline until maturity. Among the +S+N treatments, i.e. T₂, T₃ and T₄, the treatment T₄ resulted in maximum increase in soluble protein content of developing seeds. Total sugar content decreased from the initial stage of seed development till harvest. The fatty acid composition of the oil changed substantially during seed development. S and N application in three splits (T₄) resulted in the increased oleic acid (18:1) content, while decreased erucic acid (22:1) content over other treatments. Reduction in 22:1/18:1 fatty acid ratio in the oil resulted in improved quality of oil.