Apparently they are still selling these types of seeds today. Normally they are being used in school science projects.
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Irradiated with intense Gamma radiation at various levels, our 'Atomic Seeds' can produce a variety of mutations and even a never before seen changes. Exposure to Gamma rays of sufficient intensity can cause radical changes to the DNA in the seeds. The plants may grow giant (or dwarf), with strange colors, shapes or other amazing features. Some may barely sprout, others may grow faster than normal. The possibilities are truly endless.
When you order Atomic Seeds, you get 5 packs of seeds. Each of the 5 packs contains at least 20 seeds, a total of over 100 seeds. Pack #1 is the 'control' pack, which contains normal seeds that have not been irradiated. Pack #2 contains seeds that have been irradiated with 50,000 rads of Gamma rays. Pack #3 contains seeds irradiated with 150,000 rads. Pack #4 seeds irradiated with 500,000 rads, and Pack #5, seeds irradiated with 4,000,000 rads. Plant the seeds as you normally would, and observe the difference in the plants as they grow and mature.
Source: Atomic Seeds