Air potato (Dioscorea bulbifera) and Chinese yam/Light root (Dioscorea batatas) are relatives.
The former grows big aerial tubers/bulbils, the later is cold hardy.
Is it possible to somehow graft the air potato stem onto the Chinese yam roots and grow aerial tubers in a colder climate (7a)?
Yeast devil! Back to the oven that baked you! And take this tiny ad too: