Responses to irradiation treatment with 20 krad of gamma irradiation with the transformed strain of PBW containing the EGFP genetic marker show no potential reproductive advantage over its wild type ancestors, the APHIS stain of PBW. Conversely, the data indicated that the reproductive potential of EGFP stain parents treated with a 20 krad dose of irradiation would be lower that that of the nontransgenic APHIS strain of PBW due to lower fecundity rates and mating frequencies. Therefore, this suggests a lower risk of transmitting unexpected traits to wild field populations than initial projections based on APHIS strain reproductive potential.