The Plant Patent Act of 1930 was designed to encourage the cultivation of new varietiesofplants by prohibiting competitors from cultivating the offspring of those plants without permission.
New varietiesofplants (whatever techniques are used to craft them) that normally harbor relatively high levels of toxins such as celery, squash and potatoes are analyzed carefully to make sure that levels of potentially harmful substances are still in the safe range.
Because much of the loss to insects and diseases occurs after the plants are fully grown, the use of genetically engineered varieties that have higher post-harvest yields means that the farming (and irrigation) of fewer plants can produce the same total amount of food.