Foliar Application of Boron can Increase Seed Formation, Seed Yield and Oil Content in Sunflower (cv. BARI Surjamukhi-3)

Abstract— A field experiment was conducted at the experimental field of Soil Science Division, Bangladesh Agricultural Research Institute (BARI), Joydebpur, Gazipur-1701during winter season of 2022 – 2023. BARI Surjamukhi-3, a popular and promising dwarf variety of sunflower was used in this study as a test crop. The objectives were to know the effect of foliar spray of boron (B) on seed formation, seed yield and oil content in sunflower and to find out the optimum foliar dose of B for maximizing the seed yield. The experiment was conducted in a Randomized Complete Block Design (RCBD) having three replications. The fertilizer boric acid (H₃BO₃) containing 17% Boron (B) was applied at 20-25 and 40-45 days after sowing (DAS) as foliar mode. Five treatments comprised of different foliar doses of B were applied. T₁- control (spray with distilled water), T₂- 50 mg L⁻¹ B, T₃- 100 mg L⁻¹ B, T₄- 150 mg L⁻¹B and T₅-200 mg L⁻¹B. The foliar application of B significantly increased the seed formation, seed yield and yield contributing characters of sunflower. The treatment T₄ (150 mg L⁻¹B) produced the highest seed yield (2.25 t/ha) that was equal with the treatment T₅ (200 mg L⁻¹B). The minimum unfilled seed (19.00%) was recorded in T₄ (150 mg L⁻¹B), which was identical with the next higher dose T₅ (19.00%) treatment. Foliar application of B also significantly increased the oil content in sunflower seeds. The maximum oil content (39.99%) was recorded in T₅ (200 mg L⁻¹B), which was significantly higher over B control but identical to rest of the treatments. Thus, sunflower grown in B deficient Grey Terrace Soil of Gazipur (AEZ-28) found responsive to foliar application of B with regard to seed formation, seed yield and oil content.