This would seem like a good candidate for regular old cross-breeding. People in the past would select which seeds and plants to cross breed by hand. You could imagine an automated system which could cross breed 1 billion (1e9) plants at once by using cameras and ML techniques looking for good traits on each plant, using just 3% of US farmland. It doesn't need perfection - a 10% error rate simply requires 10% more pla…
It's not cheaper or faster.
And of course, now there's a massive debate whether this is GMO or not.