No abstract

2 Field experiments were conducted to determine the interactive effect of sulfur (S) and nitrogen (N) on growth and yield attributes of oilseed crops [Brassica campestris L. (V 1 ) and Eruca sativa Mill. (V 2 )] differing in yield potential. Two combinations of S and N (in kg ha −1 ): 0S + 100N (−S+N;T 1 ) and 40S + 100N (+S+N;T 2 ) were used. Biomass accumulation, leaf area index (LAI), leaf area duration (LAD), and photosynthetic rate in the leaves were determined at various phenological stages. The results showed that the combined application of S and N (+S+N) significantly (P<0.05) improved the growth and yield attributes of both the genotypes compared with N applied alone (−S+N). Genetic variability was observed between the two genotypes in response to combined application of S and N (T 2 ). Genotype V 1 had higher biomass accumulation, photosynthetic rate, seed yield, oil yield, biological yield, and harvest index when compared with genotype V 2 . Treatment T 2 resulted in 142, 95, 56, and 349% enhancement in biomass accumulation, leaf-area index (LAI), leaf-area duration (LAD) and photosynthetic rate, respectively in comparison with treatment T 1 in genotype V 1 . Seed yield, oil yield, biological yield, and harvest index were improved by 141, 171, 85, and 30%, respectively, by treatment T 2 in comparison with T 1 . In the case of genotype V 2 , increase in biomass accumulation, LAI, LAD, and photosynthetic rate due to application of treatment T 2 were 156, 137, 125 and 467%, respectively, over the results of T 1 . Seed yield, oil yield, biological yield and harvest index improved by 193, 251, 98, and 48%, respectively, with this treatment. On the basis of results obtained in this study, it can be concluded that sulfur 1217 must be included in the nutrient management package for optimum growth and yield attributes of oilseed crops. Furthermore, the yield potential of oilseed crops with low seed and oil yield can be improved using this treatment as achieved in our study in case of taramira (Eruca sativa Mill.), a genotype with low seed and oil yield.

The aim of this research was to study the effect of sulphur (S) fertilization on oil biosynthesis and its related variables at various stages of seed development, and to find possible explanations for increased oil content in the seeds of mustard (Brassica juncea L. Czern and Coss) due to S fertilization. Acetyl-CoA carboxylase activity and contents of oil, acetyl-CoA, soluble protein, total RNA, total sugar and sulphur were determined in the developing seeds of mustard grown in the field with sulphur (+S) and without sulphur (-S). The period between 10 to 30 days after flowering was observed as the active period of oil accumulation in the developing seeds of mustard. The accumulation of the oil was preceded by a marked rise in acetyl-CoA carboxylase activity and acetyl-CoA concentration, which declined rapidly when oil accumulation reached a plateau. Total sugar content decreased, while protein content increased during the active period of oil accumulation in the developing seeds (i.e. between 10-30 days after flowering). Sulphur fertilization significantly (P < 0.05) enhanced the oil accumulation in the developing seeds at all the growth stages. The increase in the oil content was 5-63% with S fertilization over the control treatment. Acetyl-CoA carboxylase activity and contents of acetyl-CoA, soluble protein, total RNA and sugar were significantly (P < 0.05) higher in the developing seeds of +S-treated plants compared to -S-treated plants. It is suggested that the increase in the oil content with sulphur fertilization may be associated with the increases in acetyl-CoA carboxylase activity through the enhancement of acetyl-CoA concentration. Further, the increased sugar content due to S fertilization provided enough carbon source and energy for oil biosynthesis.

No abstract