Why Do Some Potatoes Have Lines in Them?

Q:

Why do some potatoes have lines in them? Is that good or bad?

A:

Potatoes that have been too stored cold and then placed quickly into a warmer environment will cause small cuts or “air checks”, and while it does not affect taste, it is unsightly as it looks like someone has gouged the potato skin with a sharp fingernail.

Q&A: Timing from Harvest to Grocery Store Shelf