Abstract

                                Sunflower (Helianthus annuus L.) is an important entomophilic crop. Since self-fertility of sunflower varieties vary widely, they need the intervention of pollinators to ensure their productivity. A less self-fertile variety viz., Morden and another highly self-fertile variety viz., CO5 were used for experimentation to ascertain the role of pollinators in enhancing the productivity of sunflower. A paired plot experiment with two treatments i.e., open pollination and pollinator exclusion was conducted to explore the role of pollinators in these two varieties. Seed yield per head was more in open pollinated plots than in pollinator excluded plots. Seed set in less self-fertile Morden was doubled. Seed oil yield was 13 per cent more in open pollination than in pollinators excluded heads. In highly self-fertile CO5 variety, seed set and seed oil content were 11.4 and 5.8 per cent more in open pollination than in pollinator exclusion treatments, respectively. Yield difference between the treatment effect was significantly higher in less self-fertile Morden than in highly self-fertile CO5. Seed quality (100 seed weight, oil content, germination percentage and vigour index) were significantly more in the presence of pollinators in both the varieties. This study brought out the importance of pollinators in marginally increasing the yield of sunflower even in highly self-fertile varieties.

Key words : Helianthus annuus, Pollination, Honey bees, Self-fertile variety, Yield