If in fact that occurred.
I admit Wikipedia is not always reliable but the links in the article look legitimate to me.
'The sweet potato was grown in
Polynesia before western exploration. Sweet potato has been radiocarbon-dated in the
Cook Islands to 1000 AD, and current thinking is that it was brought to central Polynesia around 700 AD, possibly by Polynesians who had traveled to South America and back, and spread across Polynesia to
Hawaii and New Zealand from there.
[13][14] It is possible, however, that South Americans brought it to the Pacific, although this is unlikely as it was the Polynesians who had a strong
maritime tradition and not the
native South Americans. The theory that the plant could spread by floating seeds across the ocean is not supported by evidence. Another point is that the sweet potato in Polynesia is the cultivated
Ipomoea batatas, which is generally spread by vine cuttings and not by seeds.
[15]'
https://en.wikipedia.org/wiki/Sweet_potato