Open Sesame: The Pollination of Sesame Plants
Have you ever wondered how those sesame seeds got on your hamburger bun? Thanks to pollinating insects, sesame is one of the oldest cultivated crops in the world dating back to over 4000 years ago! Not only has sesame been used on the top of breads and sushi but also it has historically been used as cooking oil. Sesame flowers contain both male and female structures which allow them to self-pollinate. However, sesame can be cross pollinated by insects that carry pollen from flower to flower. When cross-pollinated, sesame plants yield more seed weight per plant than when self-pollinated.
The start of agriculture nearly 10,000 years ago, was based on the artificial selection of plants by humans, and the planting of seeds from the best plants. When plants are cross-pollinated, there is a better chance that the desirable traits from two plants are combined into one and make it desirable for selection. Without this cross-pollination by insects, sesame would probably not resemble the seed or oil we know it as today. Sesame flowers are commonly pollinated by insects of the orders: bees (Hymenoptera), beetles (Coleoptera), moths and butterflies (Lepidotera), and flies (Diptera). Like many food crops, bees are responsible for 80-90% of the pollination in sesame.
For the farmer in the crowd
Sesame can be very beneficial to rotate in a cropping system. Not only does sesame help break the cycle of other crop pests such as nematodes and fungi; but also sesame can promote pollinator colonies by providing a food source and reducing insecticide exposure. There are currently no major insect pests for sesame in the United States so usually sesame can be grown the entire season without an insecticide application. This prevents any off-target injury to beneficial insects such as pollinators. If sesame is grown in rotation with another crop that requires insecticide applications, but benefits from insect pollination, such as cotton, pollinator populations can recover during the sesame rotation year. In the event that insecticide applications are necessary, studies have shown that pollinators, especially Hymenopterans are more active during the first half of the day. With this in mind, insecticide applications in the evening would help to reduce off-target pollinator injury. Cross-pollinated sesame can yield 22-33% higher than self-pollinated sesame which can translate into a significantly higher profit per acre.
Andrade, P. B., Freitas, B. M., Rocha, E. E. M., Lima, J. A., Rufino, L. L. 2013. Floral biology and pollination requirements of sesame (Sesamum indicum L.). Acta. Sci., Anim. Sci. vol. 36: 93-99.
Blal, A. E. H., Kamel, S. M., Mahfouz, H. M., El-Wahed, M. S. 2012. Impact of pollination and fertilization of sesame production in the reclaimed lands, Ismailia Governorate, Egypt. Journal of Agricultural Sciences, 57: 121-133.
Mahfouz, H. M., Kamel, S. M., Belal, A. H., Said, M. 2012. Pollinators visiting sesame (Sesamum indicum L.) seed crop with reference to foraging activity of some bee species. Cercetări Agronomice în Moldova 45: No. 2 (150).
Oplinger, E. S., Putnam, D. H., Kaminski, A. R., Hanson, C. V., Oelke, E. A., Shulte, E. E., Doll, J. D. 1990. Sesame. Alternative Field Crops Manual. https://hort.purdue.edu/newcrop/afcm/sesame.html.
Written by Benjamin Sperry, M.S. student in Agronomy at UF/IFAS
Written for ENY5006 Principles of Entomology with Dr. Christine W. Miller