Storage of flowering dogwood (Cornus florida L.) pollen

A series of experiments was conducted with flowering dogwood (Cornus florida L.) to evaluate in vitro pollen germination both prior to and following storage at various temperatures, For all experiments, pollen was germinated on an agar-solidified medium containing 20% sucrose, Collection method had a significant effect on germination of 'Cherokee Chief', 'Cherokee Princess', and 'Cloud 9' pollen. Pollen obtained from anthers that had been collected prior to dehiscence and allowed to air-dry for 24 hours had a higher germination rate than did pollen that had undergone a desiccation treatment. None of the treated pollen tested, however, had a germination rate >25% of that of freshly collected pollen. The deleterious effect of dehydration could not be reversed by rehydration. Pollen germination was tested after 1, 4, 7, and 108 days at 5, -20, and -196 degrees C, Pollen stored at -196 and at -20 degrees C had a better germination rate than that stored at 5 degrees C. Germination was not significantly affected by length of storage, nor was there any significant temperature x length of storage interaction.