1. Irradiation Experiment.

Two years ago there was made available through the National Cash Register Company, Dayton, Ohio, a 500 mg. Radium-Beryllium neutron source. The National Cash Register Company rented it from the Eldorado Mining and Refining Company, Ottawa, Canada for their annual demonstration lecture to the public. Fear of the exposure effects of the radiation source brought a decision not to utilize it as first intended. Primarily to keep it out of the way of harming anyone, the source was stored temporarily in the attic of the Antioch College Science Building.

Dr. Harry V. Knorr exposed the seeds to the source. The exposure was made so that there was 15 cm. of solid paraffin between the seeds and the source. This was to slow down the neutrons, produced by the radiant effect of radium on beryllium. The gamma (X-rays) radiation is derived from the radium and may be the sole cause of resultant mutations.

Exposure

The following seeds were irradiated for 15 hours by the above slow neutron source. Radiation equivalent to 432 R units due to gamma rays plus neutron radiation with flux of 100,000 per second to the area.

1. 110 Sweet corn kermels, Country Gentleman, Burpee 337.

2. 110 Soybean seeds, Lincoln variety.

3. Jimson weed seeds.

4. Ruby Red Petunia seeds.

5. Salmon Pink Petunia seeds.

The following seeds were irradiated for one hour by the slow neutron source. Radiation equivalent to 28.88 R units due to gamma rays plus neutron radiation with flux of 100,000 per second to the area.

6. 110 Sweet corn kernels, Country Gentleman, Burpee 337.

7. 110 Soybean seeds, Lincoln variety.

8. Jimson weed seeds.

9. Admiral Petunia seeds.

10. King Henry Petunia seeds.

The following seeds were irradiated for 15 minutes by the slow neutron source. Radiation equivalent to 7.22 R units due to gamma rays plus neutron radiation with flux of 100,000 per second to the area.

11. 110 Sweet corn kernels, Country Gentleman, Burpee 337.

12. 110 Soybean seeds, Lincoln variety.

13. Jimson weed seeds.

14. White Perfection Petunia seeds.

F₁ generation

1 and 2 were grown in the field the sumer of 1948. Plants were phenotypically normal. Rabbits ate all the soybeans of 2. 6 and 11 were grown in the field the summer of 1949. They too produced phenotypically normal plants. Unfortunately there were no controls set aside. 1, 6, and 11 were self‑pollinated to produce F₂.

F₂ generation

Ten seeds of each F₁ from treatment 1 were sown in the greenhouse and seedlings observed for variation. There were 19 different F₁ progenies in this treatment. All showed some variation. The frequency of the different variations is as follows:

Runty fine stripe............... 7

Fine stripe..................... 2

Fine stripe frayed leaves....... 1

Lethal yellow................... 2

Albino.......................... 1

Runty or small.................. 5

Frayed leaves................... 2

Wavy leaves..................... 1

Oily or greasy green............ 2

Narrow leaves................... 1

Some progenies showed more than one type of variation, thus accounting for the 24 variants among the 19 F₁ lines in this treatment. F₃ progeny showed wavy leaves variant not to be inherited, but both oily or greasy green variants, the albino variant, and both lethal yellow variants to be transmissible by inheritance, and therefore to be bona fide mutants. Other variants have not been progeny tested to determine their status as hereditary characteristics (mutants).

Twenty seeds of each F₁ from treatments 6 and 11 were sown in greenhouse and seedlings observed for variation.

Out of 23 different F₁ progenies from treatment 6 three showed the following variations (one each):

Lethal yellow

Albino

Fine stripe

None of these have been tested to determine their status as hereditary characteristics.

Out of 31 different F₁ progenies from treatment 11, five showed the following variations (one each):

Albino

Yellow‑green lethal

Wavy leaved

Fine stripe

Oily or greasy green

None of these have been tested to determine their status as hereditary characteristics.

Should any one be interested in these corn variants or in irradiated soybean seeds, Jimson weed seeds, and petunia seeds not yet processed, I shall be glad to furnish any upon request.