Gamma gardening

When I was little I read about using radiation to try to induce useful mutations. I heard nothing more for decades. They're still doing it.

Modern genetic engineering has replaced the need for atomic gardening, but the legacy is still carried forward by the Institute of Radiation Breeding in Japan, which currently owns the largest, and possibly the only surviving gamma garden in the world, at Hitachiōmiya in Ibaraki Prefecture. The circular garden measures 100 meters in radius, and enclosed by an 8-meter high shielding dike wall. Species within are irradiated with gamma rays from a cobalt-60 source placed inside a central pole.

The blurb for the Rio Red grapefruit somehow doesn't mention exactly how "scientists tried to breed" it, but wikipedia says they used thermal neutrons instead of gammas (as the first link says--though maybe the gamma source is just the last one running).

I wonder why the USCitrus site is cagey about that... It couldn't be because some people freak out when they hear the word "radiation", could it? "Frankenfood" ... "Godzilla in your juice glass" I wonder how Godzilla would taste sauteed in olive oil with a little pepper and garlic.