[racer-v]

it took a really, really long time to transform wild plants and animals into useful domesticated varieties.

Really? The wild plants and animals were already useful. So from day one, the transitional forms to the domestic varieties were useful as well.

Without those, you really are better off remaining a hunter-gatherer.

There's not a sharp division between hunter-gatherer and agriculturalist. Sedentism preceded agriculture. As people accidentally dropped seeds around their dwellings (or discarded them with the trash), they gradually became gardeners and then farmers.

[Gibbon1]

You can consider wheat. Originally the number of seeds produced by a wheat stalk was small. Which meant needing to sow a high proportion of your crop for next year. With domestication the yields slowly increased over several thousand years.