Foliar Application of Boron can Increase Seed Formation, Seed Yield and Oil Content in Sunflower (cv. BARI Surjamukhi-3)
Abstract
Afield 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 (H BO ) containing 17% Boron (B) was applied at 20-25 and 40-45 days after sowing 3 3 (DAS) as foliar mode. Five treatments comprised of different foliar doses of B were applied. T-control (spray with distilled 1 water), T-50 mg L-1 B, T-100 mg L-1 B, T-150 mg L-1 Band T-200 mg L-1 B. The foliar application of B significantly 2 3 4 5 increased the seed formation, seed yield and yield contributing characters of sunflower. The treatment T (150 mg L-1B) 4 produced the highest seed yield (2.25 t/ha) that was equal with the treatment T (200 mg L-1B). The minimum unfilled seed 5 (19.00%) was recorded in T (150 mg L-1B), which was identical with the next higher dose T (19.00%) treatment. Foliar 4 5 application of B also significantly increased the oil content in sunflower seeds. The maximum oil content (39.99%) was recorded in T (200 mg L-1B), which was significantly higher over B control but identical to rest of the treatments. Thus, 5 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.
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Introduction
Sunflower (Helianthus annuus L.)is considered as an essential oilseed crop, which grows well in Bangladesh during winter season. The oil of sunflower contains plenty of essential fatty acid such as linoliec and linolenic acid in comparison with rapeseed and mustard oil. But Rabi (winter) season is considered the best for producing sunflower in Bangladesh. The southern regions of Bangladeshis most suitable to grow sunflower after harvesting T. aman rice (BARI, 2023). The area and production of sunflower in 2020-2021 was 0.012 lakh ha and 0.014 lakh MT, respectively (DAE, 2022) and its cultivation and production are gradually increasing. Sunflower, has been recorded to be particularly sensitive toB deficiency and normally used as an indicator for the assessing available Bin soils (Oyinlola, 2007). As Bis essential for crop growth and can be applied according to crop demand, harmful effects also detected by the applying overdose in early phases of growth (Oyinlola, 2007 and Shorrocks, 1997). Foliar application may be required when the demands are higher than the boron supplied through the soil application. The doses of boron may affect either by positively and negatively the yield and the components in vegetative and reproductive stages of sunflower. The reproductive growth is much sensitive for boron than vegetative growth (Asad et al., 2003). Chatterjee and Nautiyal (2000) reported that the pollen viability and abortion of stamens and pistils, which contribute to poor seed set due to malformed capitulums and consequently low seed yield, due toB deficiency at flowering time. The demand of boron to sunflower varies depending on the stage of plant growth. The critical content of boron at the time of sunflower emergence is 20 mg kg-1 of soil (Asad, 2002). That is the reason why some farmers prefer foliar nutrition when applying micronutrients. Many scientists have described the effects of foliar application of boron on the growth and development of sunflower. Boron is an important element, which influenced yields of many crops like sunflower, cotton (Dodas, 2006). However, in depth research regarding the foliar application of Bin sunflower for seed formation and its yield is scarce in Bangladesh. Therefore, the present study was carried outwith following objectives: (i) to know the effect of foliar spray of boron (B) on seed formation, seed yield and oil content in sunflower and (ii) to find out the optimum foliar dose of B for maximizing the seed yield.
Conclusion
Foliar application of B two times at 20-25 and 40-45 days after sowing of seeds, i.e. in vegetative and pre-flowering stage, respectively significantly contributed to increase seed formation, seed yield, biomass yield, oil content in sunflower (BARI Surjamukhi-3). Boron application in the form of foliar mode also decreased seed sterility and increased the B concentration and uptake by the plants. Boron @ 150 mg L-1 as foliar application containing the volume of 10 liters per plot (2.5 Lm-2) appeared as the best dose for the cultivation of sunflower in Grey Terrace Soil under AEZ 28 and similar soils in Bangladesh. NOVELTY STATEMENT The present findings indicated that up to a certain level of B application to soil, N P, K, Zn and B content showed synergistic effect. This type of research was conducted first time in Bangladesh AUTHOR’S CONTRIBUTION Most. Bilkis Banu: Conceptualization and methodology of the study. Supervision, soil chemical analysis collection of data and analysis using Statistics10. Writing results and discussions,
