The present invention relates to a method for producing potato
tubers comprising grafting a potato plant as scion on a solanaceous
rootstock and culturing the resulting graft plant by hydroponics to form
aerial tubers. etc..."

One little problem. Tubers have thin skins and are designed to grow
underground, where they have a constant supply of moisture. The surrounding
earth keeps them from getting bruised. Also, potatoes exposed to light develop
green pigment, which ruins them.

Iris,
Central NY, Zone 5a, Sunset Zone 40
"When you come to a fork in the road, take it." Yogi Berra