Linked article claimed it was undertaken to prevent seed counterfeiting.

Edit: (I personally know basically nothing about the law or how it’s been implemented.)

> Also, what's the connection to the high yield ones?

The high yield seeds are created by cross pollinating certain varieties. When the high yield seeds are planted, the new seeds should be eaten -not re-planted- since they will give poor yield.

So a counterfeiter can just buy cheaper food-seeds and resell them as expensive high-yield seeds.

Instead of doing things like securing their supply chains, the reaction of the seed companies is to... just make anyone else selling seeds illegal.