Optimizing sunflower (Helianthus annuus L.) hybrids growth, achene and oil yield through soil applied sulphur and zinc

Sunflower growth and yield depend on nutrient availability, with a comparatively higher requirement for sulphur (S) and zinc (Zn). Therefore, implementing appropriate agronomic practices, particularly crop fertilization, is essential to enhance productivity and improve crop quality. The current research was carried out in two consecutive years (2021 and 2022) to study the growth and yield response of sunflower hybrids to S and Zn levels at Agriculture Research Station District Swabi of Khyber Pakhtunkhwa province of Pakistan. Four levels of S and Zn each were tested which include 0, 20, 30 and 40 kg S and 0, 10, 15 and 20 kg Zn ha^-1 applied to two locally produced hybrids i.e. PARSUN-3 and PARSUN-1. The experimental results showed that both S and Zn had significantly affected growth and yield of sunflowers. Applications of 40 kg S and 20 kg Zn ha^-1 produced taller plants (7.5 and 8%) with delayed flowering (13 and 4.5%) and maturity (3%) over control. Also yield and yield components of sunflower were significantly higher at these levels of S and Zn. Application of 40 kg S and 20 kg Zn ha^-1 increased yield by 68 and 33% over control. PARSUN-3 hybrid, which is a dwarf genotype and short growth cycle produced higher yield and yield components. Yield and yield components of sunflower were also higher with addition of 30 kg S and 15 kg Zn ha^-1. PARSUN-3 with addition of 30 kg S and 15 kg Zn enhanced growth and yield of sunflower and is recommended in the study area. Further research and field trials could provide deeper insights into the long-term impacts of this approach across different crop varieties and environmental conditions.