[Obi_Juan_Kenobi]

Plant patents are just as onerous as utility patents. Creating exclusive new breeds is the entire intended purpose of this type of patent, one of only six (or seven?) in the US.

https://www.uspto.gov/patents-getting-started/patent-basics/...

Toxic externalities, as you say, occur readily in traditional breeding when creating hybrids. I find it very difficult to believe you have any experience or background in breeding or agriculture if you're not aware of this. Targeted modifications are much easier to understand and predict; it's a matter of changing a single locus vs. thousands.

Certain modifications could be foolish, but for reasons we understand. Extant transgenics focus on e.g. the Shikimic acid pathway (roundup ready) precisely because it is absent outside of plants, and therefore unlikely to cause complications prima facie.