That's another Asomov thing I really kind of liked. It wasn't hyper-oats though. If you think about it oats, like any grass, would simply require too much god damn land. I liked Psycho-Pass's idea, but I didn't really like the implementation and the whole virus thing was where the first season started falling apart. Why a virus? How does that make hyper-oats any more productive than regular crops? Japan has fuck-all for landspace, why oats?
Humans in the Robot books mostly ate yeast bacteria. Yeast cultivated and genetically engineered to taste and look like ANYTHING. Even fresh strawberries turned out to simply be marvels of yeast engineering. They could grow tons of the stuff in huge vats, really quickly, in order to feed all of the people on Earth.