Not just a Cold War-era relic...
...the use of radiation to introduce genetic changes in food (aka "atomic gardening") is alive and well today.
What's more, the Times adds, nearly 2,000 gamma radiation-induced mutant crop varieties have been registered around the world, including Calrose 76, a dwarf varietal that accounts for about half the rice grown in California, and the popular Star Ruby and Rio Red grapefruits, whose deep colour is a mutation produced through radiation breeding in the 1970s. Similarly, Johnson tells Pruned that "most of the global production of mint oil," with an annual market value estimated at $930 million, is extracted from the "wilt-resistant 'Todd's Mitcham' cultivar, a product of thermal neutron irradiation." She adds that "the exact nature of the genetic changes that cause it to be wilt-resistant remain unknown."
The atomic gardening photos from Life magazine in 1961 are kind of great.