Effect of Sulphur Application on Photosynthesis and Biomass Accumulation of Sesame Varieties under Rainfed Conditions

Oilseeds yield response to sulphur (S) has been well investigated but the dynamics of total biomass accumulation (TBA) and partitioning by sesame plants in response to S are not well understood. This study was initiated to investigate the effects of S on sesame, in which four sesame varieties V-1,V- SG-27; V-2,V- SG-30; V-3,V- SG-36; V-4,V- SG-51 and four S treatments T-1, 20; T-2, 30; T-3, 40; T-4, 50 kg ha(-1) were used. Results revealed that the leaf area index and photosynthetic rate of sesame varieties were significantly higher under T-3 with V-3. Similarly, S fertilization considerably increased the TBA and maximum TBA was reached at late-flowering with V-3 in T-3. Relative to T-1, plants in T-3 had 33 and 23% higher capsule and seed biomass, respectively. Furthermore, total S accumulation and distribution in different plant organs changed with growth stage, at pre-flowering and mid-flowering stage maximum S was found in the stem, whereas at late-flowering and full-maturity stage highest S was recorded in reproductive parts. These results implied that S fertilizers should be applied to agricultural fields to improve oilseed production and by selecting the appropriate and area-specific genotype we can increase sesame seed yield under rainfed conditions.