Ultraviolet irradiation of maize (Zea Mays L.) pollen grains : II. Pollen genotype effects on plant characteristics.

Mature pollen grains from two single cross (F1) hybrids, Wf9 X H55 and K64 X K55, were exposed to eleven levels (0 to 6.80 erg/cm(2) × 10(5) at 0.68 intervals) of ultraviolet irradiation and then were used to pollinate their source. Height and kernel characteristics (kernel weight, weight/100 kernels, kernel number) of individual F2 plants produced by the normal F2 kernels obtained from these pollinations were measured within each level and population. Highly significant exposure X population interactions were found for all characters, indicating that the effect of irradiation depended on the genetic source of the pollen grains. Increasing exposure increased or did not change the mean of Wf9 X H55 and decreased the mean in K64 X K55 for all characters. For coefficient of variation values, the interaction, exposure X population, was not significant for any character measured, indicating that irradiation-induced variability was unrelated to pollen source. The results indicate that pollen source strongly influenced the effect of ultraviolet irradiation on plant means but had no influence on variability.