I see you are in Canada so I hope someone in your area who grows
Yacon (Smallanthus sonchifolius) will be able to help you with a trade or at least know of a source where you can purchase seeds or tubers. With so many postal rules and regulations when it comes to shipping plants it may be difficult to acquire unless you can find a source in Canada. I googled and I see that Annie's Annuals sells the tubers:
http://www.anniesannuals.com/p... but I'm not sure if they ship to Canada.