This study investigated pollen viability, pollen longevity,and pollen size using different materials, including the tetraploid cultivar Alamo, the octoploid cultivar Cave-in-Rock, and transgenic Alamo plants. Pollen grains were collected from fieldgrown Alamo and Cave-in-Rock plants, and greenhouse-grown transgenics. Pollen size was in the range of 42.5 to 54.0 μm; no significant difference was observed in average pollen size between transgenic and control plants. Increasing
temperature and ultraviolet-B irradiation negatively affected pollen viability and longevity,while relative humidity had only limited impact.