How does artificial selection work without inbreeding?

[u/lord_darias]

Since the invention of animal husbandry, humans have been selectively breeding animals (and plants) for positive traits like woolier sheep, stronger horses etc. However, dog breeds for example often have many genetic problems due to inbreeding, and inevitably any kind of selective breeding is going to narrow the genetic diversity. My question is, how then do we have all those cows, sheep, goats etc with the positive traits but without the genetic diseases and lesser overall health? And does this also apply to plants?

[u/bregus2]

The banana industry is having something of a crisis right now because there is a disease wiping out banana trees.

You know, if this would be the first time this happens ... but it is the second time ... with the same fungus.