In The Mid-20th Century, Radioactive Material Was Used Successfully In Which Of These Unlikely Applications?
We have long strove to modify our crops to be more disease resistant, yield better (and more) produce, and otherwise be better versions of their wild ancestors that we took interest in centuries upon centuries ago. Before the advent of modern genetically modified foods, where scientists actively and precisely manipulate the genome of the plant, the process of modifying crops was a laborious one akin to breeding dogs to select for traits. You simply had to spend a lot of time with lots of trial and error to produce a plant that had a trait you were looking for.
In the mid-20th century, however, a new technique was developed. This technique was a middle road between the agonizing slowness of generational breeding and the speed and precision of modern genetic work: atomic gardening. In the 1950s, 60s, and early 70s, atomic energy of all types seemed like the key to all the promises of the future. Researchers used radioactive materials to create “atomic gardens” (also known as gamma gardens) in a bid to force mutations in plants and create better, hardier, and interesting variations of the plants. Gardening clubs and individual gardeners helped by planting irradiated seeds produced by the research.
Arranged in a circular fashion, atomic gardens had a simple premise. Place a radioactive substance in the center of the garden, typically Cobalt-60, and then grow the plants in concentric circles around the source as a way to naturally control the dosage. The closest plants would get the highest dose, and if the garden was large enough, the dosage would be negligible by the time you got to the rings furthest from the center.
While this method of gardening yielded many unusable mutations and the crops closest to the radiation source almost always withered from exposure, the outer plants would sometimes develop useful mutations. For example, the “Todd’s Mitcham” cultivar of peppermint (released in 1971) was developed in this fashion starting with experiments in 1955 and is now popular in the peppermint industry thanks to its strong resistance to disease. Furthermore, many crops around the world trace their origins back to mid-century atomic gardening experiments including variations of food staples like rice, wheat, and tomatoes.
Although atomic gardening is not as popular as it once was, it is starting to experience a renaissance and research continues at many national laboratories—like the multi-acre atomic garden at the Institute of Radiation Breeding in Hitachiohmiya, Japan (seen in the photo here)—that have been in operation for decades and still produce new and novel variants of plants with regularity.
Image courtesy of the Institute of Radiation Breeding.