[phryk]

With the proliferation of patents and the marketing blitz by these companies, we'll have only a handful of varieties that are sterile. There will be no new varieties coming out of natural cross pollination because we are left with sterile patented varieties.

That makes sense. But it only seems to apply to species that have already been thoroughly reshaped by humanity (pets, food and similar). Not what you normally think of when someone goes crying about biodiversity. To me it just seems like a more efficient/adapted successor generation to our current designed species.

Exactly. The viruses, bacteria and pests are evolving naturally; they are increasing their resistance to the existing pesticides. With the sterile varieties, there is no evolution, no adaptation to the changing environmental conditions and the changing pests.

Yes, and with biotech we're able to adapt these design-species much faster than 'natural' evolution ever could.