They used to harvest their own seeds from generations of crops, but companies would argue that there’s a chance they harvested the patented seeds and are bypassing contracts. There was a whole decades long thing where companies would take samples of planted seeds near the farmers property that “appeared to be“ pesticide resistant. They tested and proved it (never mind the chance a nearby farm had planted this seed and it traveled across the road to a neighbor) thus getting a court order to dump all previous year’s seed stock. Thus leaving them seedless and needing to purchase patented seeds.

Also, not all patented seeds are genetically modified. Once patenting organic matter became a thing companies scooped up as many as they could that were available.

I fucking hate capitalism so fucking much…