|Fig. 1: Atoms for Peace propaganda poster showing possible uses of radioisotopes on the farm. (Source: U.S. National Archives)|
The post-war period was characterized by a substantial increase in proposed peaceful applications for the atom. In 1953, Eisenhower gave his "Atoms for Peace" address before the general assembly of the United Nations. While some regard this as largely propaganda to cover for the United States promptly continuing to build its arsenal at a rapid pace, it also led to some rather crazy peaceful applications of nuclear technology in the civilian sphere. 
Many of these applications resulted in advances that are still in use today, from radioisotope thermal generators which paved the way for deep space probes to advances in powerplants that enabled the large-scale nuclear power generation we use today. 
Some projects, however, were decidedly less so, whether simply in nuclear powered ships that didn't catch on, or Project Plowshare, which had the goal of using nuclear explosions for large excavation projects. [3,4] Another of these more fanciful applications were the gamma gardens, and the atomic gardening societies that also found popularity. Official Atoms for Peace propaganda was produced. (See Fig. 1.)
The gamma gardens were research gardens, where a radiation source of Cobalt-60 would be hoisted on a tower at the center of a circular field. Plants in the field would be exposed to varying degrees of radiation, and accumulate mutations in their DNA. The radiation source would then be lowered into a bunker, and researchers would examine the plants, seeking favorable mutations. These would then be further developed, until useful variants were produced. This process is still used in many areas, as the equipment is easier to set up and less expensive than equivalent gene-modification equipment.  It also has the possible advantage that it introduces no new genes, only accelerates the natural shuffling process of the existing genome.  It should be noted here that the resulting plants are not themselves radioactive.
|Fig. 2: Muriel Howorth (right) showing garden writer Beverly Nichols a peanut plant grown from irradiated seed. (Source: Wikimedia Commons)|
Perhaps more interesting is the do-it-yourself aspect of atomic gardening that had a brief popularity. The Atoms for Peace effort also permitted citizens to get radioactive sources; one such citizen was an oral surgeon from Tennessee named CJ Speas, who irradiated seeds in his backyard and then sold them to home gardeners or to kids for science projects.  He would also attend home-and-garden shows, and encourage people to try their own atomic gardening.
One of his customers was an English woman named Muriel Howorth, who started the Atomic Gardening Society to promote the cultivation of gamma-irradiated seeds in gardens.  As part of her advocacy efforts, she hosted dinner parties where she served food grown from irradiated plants, including irradiated peanuts, like the plant she holds in Fig. 2.  She also published society bulletins, and even put on an all-woman pantomime titled Isotopia.  This show featured a history of the atom from Democritus to the bombs, included an interpretive dance of smashing an atom, a Geiger counter (played by one of the women), and even included "[a] spirited representation of a rat eating radioactive cheese." 
Of course, these rather whimsical atomic programs eventually faded as well. Civilians can no longer apply to receive a radiation source. Radiation plant breeding has been largely supplanted by gene editing. There are, however, a few cultivars still grown today which date to these earliest gamma gardens, including a kind of peppermint and the Rio Star grapefruit, which accounts for 75% of grapefruit grown in Texas. 
So the next time you bite into a grapefruit, take a moment to recall a rather charming part of atomic history.
© Arul Suresh. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
 Krige, J. "Atoms for Peace, Scientific Internationalism, and Scientific Intelligence," Osiris, 21 161 (2006).
 G. R. Schmidt, T. J. Sutliff, and L. A. Dudzinksi, "Radioisotope Power: A Key Technology for Deep Space Exploration," in Radioisotopes - Applications in Physical Science, ed. by N. Singh (InTech, 2011), p. 419.
 M. Dresser, "Celebrated Nuclear Ship Rests in Baltimore," Baltimore Sun, 31 Jul 11.
 D. Powell, "Operation Plowshare," Physics 241, Stanford University, Fall 2014.
 W. J. Broad, "Useful Mutants, Bred with Radiation," New York Times, 28 Aug 07.
 H. A. Curry, Evolution Made to Order (University of Chicago Press, 2016), p. 182.
 P. Johnson, "Safeguarding the Atom: The Nuclear Enthusiasm of Muriel Howorth," Brit. J. Hist. Sci. 45, 551 (2012).
 "The Explosion and All," Time 56, No. 18 (30 Oct 1950), p. 40.