Response of sunflower varieties to silicon in the coastal region of Bangladesh

Silicon is known as a beneficial plant nutrient element; however, its beneficial role in sunflower grown at coastal ecosystem of Bangladesh is yet not documented. This experiment was conducted in a coastal region to examine the effect of Si supplementation on the growth, yield and Si uptake of different varieties of sunflower. The experiment was set at Kartikpasha village of Dumki upazila, Patuakhali district during Rabi (dry) season of 2024. The field trial followed 2- factorial design with two doses of Si (0 and 60 kg Si ha-1 from CaSiO3) and six varieties of sunflower (Chuni1, Chuni2, Unisun, Hysun36, BARI surjomukhi1, and BARI surjomukhi2). Silicon application to soil significantly increased seed and straw yields of sunflower showing 2.97 and 5.23 t ha-1 in 60 kg Si ha-1 treatment, and 2.76 and 4.64 t ha-1 in Si control treatment, respectively. Silicon application had greater effect on straw yield than on seed yield. However, varieties Chuni2, Unisun, Hysun36 and BARI surjomukhi2 were found more responsive to Si application. The Si concentration of straw widely varied showing a range of 0.80-1.57 % over the varieties, with no significant variation for Chuni1 and Chuni2 varieties. Thus, Si application at 60 kg ha-1 rate could be suggested for improvement of yield and Si concentration of sunflower having Unisun, Hysun36, BARI surjomukhi1 and BARI surjomukhi2 identified as highly Si responsive sunflower varieties. Bangladesh J. Agri. 2026, 51(1):1-14