Study on the diversity of flower visiting insects and their effect on sunflower yield

抄録

The field experiment was conducted from November 2022 to March 2023 at the research farm of Sher-e-Bangla Agricultural University, Dhaka- 1207 and BARI, Gazipur-1701 to explore the diversity of pollinators in sunflower and their influence on seed yield. The experiment was designed using a Randomized Complete Block Design (RCBD) with five replications. It comprised four distinct treatments : T₁: Open flower, T₂: Netting flower at night, T₃: Netting flower the day and T₄: All time netted. The insect pollinator population consisted of eleven species from seven families and four insect orders. Among them one species of Lepidoptera, six species of Hymenoptera, two species of Diptera and two species of Coleoptera were identified visiting sunflower floral heads. The relative abundance of four Apis species, i.e. A. mellifera L., A. dorsata, A. cerana and A. florea varied on an hourly basis. A. mellifera L. was the most frequent visitor in open field (14.46) and had the highest pollination efficiency index. These insects also made a considerable contribution to the increase in thd total number of seeds per head, seed weight, oil content, and seed germination percentage compared to self-pollination. The most frequently observed pollinator was the honey bee with a higher number observed in the open field (6.75). Germination percentage was higher in the open field (91.67) and the maximum oil content of the seed was also found in the open field (39.55%). The highest yield was found in the open field (855.00 g) and the lowest was found in completely netted (439.60 g). From the study, it may be concluded that, the intrinsic value of sunflower seeds depends on the condition of pollinators and beekeeping is essential for ensuring the high-quality production of sunflower seeds.