See also: potatoes - early varieties would likely cause death by solanine poisoning, as well as tasting vile.
Almonds - originally full of cyanide and apparently tasted of bleach.
Rhubarb - stalk lovely, leaf gives excruciating death by oxalic acid poisoning.
How desperate and hungry were our ancestors to turn lethal poisons into food crops?
And it would have saved a lot of bother if they’d never bothered with the gluten grains. Rice deserved better.