Understanding the Prehistoric Presence of the Sweet Potato in Polynesia: An Investigation on Seed Floatability and Viability

The sweet potato, originally domesticated in Central and South America is widely cultivated and important in Polynesian societies. The crop was thought to have been introduced to the Pacific islands through contact with European travelers, but 1000-year-old sweet potato archeological remains indicate the crop arrived much earlier. One commonly proposed introduction process are two-way ocean voyages by early Pacific sailors between Polynesia and South America. This has recently been challenged by genetic evidence that predate human presence in the region and suggest arrival of the plant in Polynesia, circa 50 thousand years ago. Sweet potato seeds are found inside capsules capable of floating; therefore, arrival of seeds by oceanic drift is a proposed dispersal process. We test two aspects of the drift dispersal hypothesis: 1) how long can seed capsules remain floating on seawater and 2) how does contact with seawater impact seed viability. Oceanic surface drift simulations determined that 82 days was the minimum duration of a successful voyage. In our experiment, the seed capsules underwent 120 days of seawater exposure. The seed capsules failed to maintain buoyancy for the required duration, sinking after 19 days on average. However, sea water exposure only reduced seed viability by approximately 65%. These findings indicate sweet potato seeds were capable of surviving a drift voyage from South America to Polynesia. However, they would need a vegetation mat or other medium to provide buoyancy for the duration necessary.The Byrd Polar and Climate Research CenterThe College of Arts and Sciences HonorsNo embargoAcademic Major: International Studie