5. The following results have been obtained to date on haploid frequencies in seedling progenies from untreated and x-rayed (1500 r-units) pollen:
| N | 2N | |
| From untreated pollen | 66 | 126,308 |
| From x-rayed pollen | 31 | 24,619 |
The haploids were identified with the aid of recessive seedling genes, stomate examination and root-tip chromosome counts.
L. F. Randolph