1. “Primex” white mustard, Sweden, 1950 2. “Chlorina Mutant” tobacco, Indonesia, about 1950 3. “Shafer’s Universal” bean, Germany, about 1950 4. “Regina II” summer oil rape, Sweden, 1953 5. “Weibull Stralart” fodder pea, Sweden, 1957 6. “Sanilac” navy bean, Michigan, 1957 7. “Pallas” barley, Sweden, 1958 8. “N. C. 4X” peanut, North Carolina, 1959 9. “Florad” oats, Florida, 1960 10. “Seaway” bean, Michigan, 1960 11. “Alamo-X” oats, Texas, 1961 12. “Gratiot” bean, Michigan, 1963 13. “Pennrad” barley, Pennsylvania, 1963 14. “Yukon-1” carnation, Connecticut, 1963
In these instances no desirable changes appeared in the plant grown directly from treated seeds, but they appeared several generations later. In most cases hundreds of thousands of plants were examined before the desirable ones were found. The desired changes were almost always accompanied by undesirable ones, and years of cross-breeding and “purifying” were necessary to obtain usable varieties.
The technique of radiation breeding can be used on any form of life where large numbers can be grown and discarded at little cost. The output of penicillin has been increased a thousandfold by repeated mutations caused in the microorganism producing this antibiotic. Several studies on radiation breeding of poultry have been started.
An ingenious reverse twist of induced mutation is being applied in the field of plant diseases. While some scientists are irradiating seeds and plants in an effort to obtain disease-resistant mutations, others are irradiating the fungi which cause the diseases. They hope in this way to foresee the new strains of pathogenic microbes that will occur naturally in order to breed resistant plants before the new diseases appear.
Some claims have been made that radiation can stimulate plant growth, germination, earlier maturity, and so on. Similar benefits are sometimes claimed for human health. These allegations are almost never proved in reputable laboratories. It seems likely that radiation is stimulating, in the words of one authority, “only in the sense that a pruning knife is stimulating.”
Can Radiation Destroy Germs and Insects?
Food technologists have studied ways of preserving food with radiation for more than ten years. Their findings indicate that complete sterilization of food with radiation requires doses so high (2 to 6 million roentgens[2]) that cost is prohibitive at present, and the food often becomes distasteful. These amounts of energy completely destroy the microbes and enzymes which normally cause food to putrefy.
If radiation is to be used in preserving food, it will probably be as a supplement to conventional methods of heating and freezing. “Pasteurizing” with radiation to destroy most (but not all) of the microbes in meat or fruit or vegetables is accomplished with less than five per cent of the dosage required for sterilizing. Such treatment does not alter flavor or texture appreciably and could be used to prolong the refrigerated “life” of many fresh foods. It is the responsibility of the Federal Food and Drug Administration to determine that no threat to human welfare could possibly result before approving the use of high-energy radiation to preserve foods.
With agricultural products stored dry, such as grain, tobacco, and wool, the chief agents of damage are not microbes, but insects. The loss of stored field crops caused by insects is estimated at $200 million annually in the United States. Deinfesting such goods with radiation doses in the “pasteurizing” range promises to be practical and causes no apparent change in the product.
Like many other foodstuffs, potatoes are often stored for months between harvest and use. Precaution must be taken to prevent their deterioration during storage not only from decay but also from sprouting.