[Miss Marple]

My only concern is that non-modified plants' genetic code be preserved in some way, so that the originals aren't lost forever.

[goldstategop]

Back up copies can be made and stored in the vaults of a lab. That way we won't lose the originals if we ever need them. Although I can't imagine why we would really miss them if modified crops really give people immunity to disease, add missing nutrients to their diet without need for additives, and just plain taste good.