The population of Europe exploded with the introduction of the potato.
Note what happened in Ireland when it was removed...the Irish famine... about 1.5 million starved to death.
There are 2,000 varities of potatoes still in Peru. If the Irish had chosen two or three others to grow there is a good chance they would have had one that was immune to to the fungus that killed their potato crops.
I think it was Frederick the Great who became a champion of the potato and promoted it to his people. I found the history incredibly fascinating, how the humble spud changed the course of history.