2. Notes on haploids. In seedling progenies grown from X-rayed pollen and ultraviolet treated pollen, a large number of haploids was found. The frequency of haploids in the ultraviolet progenies was somewhat higher than in the X-ray progenies, though in both eases the frequency was not very greatly increased over the control. An interesting feature was a distinct tendency for haploids to occur more frequently in progenies of certain female parents than of others; in fact, the untreated female parent had a greater influence on the haploid frequenoy than the treated male parent. This suggests that the factor limiting haploids may be their inability to survive to the seedling stage, and that a considerable number of haploids may be included among the "germless seeds" resulting from the use of irradiated pollen. (See also Randolph, this News Letter)
Fifty-five haploids were transplanted to the field and grown to maturity. They showed rather surprising fertility. Forty-one of them produced silks, several from two ears, and all of the ears were pollinated. Twenty-seven of the forty-one plants set seed, and ten of these yielded ten or more seeds per plant. The highest numbers of seeds harvested per plant were 97, 47, and 43 respectively, in each case from a two-eared plant.
L. J. Stadler