Well, since it’s #bus_educational, this is:

[The Quote]
The ancient people did not eat roots. There are no edible roots in the wild. No there! Except the root of valerian, ginseng and wild garlic. It was invented by some gorgeous anthropologist, and his fantasies are not quoted in school textbooks for a dozen years. Root crops were cultivated by already settled tribes. But there were mushrooms and berries, but no word about it.
[ / Quote ]

And where did the settling tribes get the original material for cultivation? There were eating roots. Gorec (aka grapefruit), goat lapchatka, sweet, pasternak, topinambur, goat, shooter, batat, wild potatoes - and this is just what first came to mind.