Did you know that the mint flavour in your chewing gum, and the ruby-red grapefruit on your breakfast plate, both come from cultivars created through a deliberate irradiation? I'd never heard of this before, but apparently in the 50's and 60's many countries set up "gamma gardens" to experiment with exposing food plants to powerful gamma radiation, with the hope of spontaneously creating new cultivars with beneficial mutations. The disease resistant properties of commercially-grown mint, and the colour of the "Rio Star" grapefruit grown widely in Texas, were "created" using this method. The Institute of Radiation Breeding in Japan conntinues such research today; here's an aerial view of one of their "gamma gardens":
Check out the article "Atomic Gardens" from the blog Pruned for a fascinating look into the history of gamma gardens, including this explanation of the design of the gardens themselves:
The circular spatial form of the gamma gardens, which in aerial view uncannily resembles the radiation danger symbol, was simply based upon the need to arrange the plants in concentric circles around the radiation source which stood like a totem in the center of the field. It was basically a slug of radioactive material within a pole; when workers needed to enter the field it was lowered below ground into a lead lined chamber. There were a series of fences and alarms to keep people from entering the field when the source was above ground.
The amount of radiation received by the plants naturally varied according to how close they were to the pole. So usually a single variety would be arranged as a 'wedge' leading away from the pole, so that the effects of a range of radiation levels could be evaluated. Most of the plants close to the pole simply died. A little further away, they would be so genetically altered that they were riddled with tumors and other growth abnormalities. It was generally the rows where the plants 'looked' normal, but still had genetic alterations, that were of the most interest, that were 'just right' as far as mutation breeding was concerned.
Pruned: Atomic Gardens