Requirements for seed germination in North American pawpaw (Asimina triloba (L.) Dunal)

North American pawpaw is a temperate species in the mostly tropical Annonac eae. 4 small proportion(12%) of the seed population used in this study germ inated after removal from the fruit. The remaining seed required 8 weeks of chilling stratification to satisfy dormancy. In addition, pawpaw seeds dis played a moderate form of recalcitrance. Seeds lost 50% viability when seed s were dried from their initial 37 to 25% moisture. Critical value for tota l loss in viability was between 15 and 5% moisture. Also, following stratif ication, pawpaw seeds germinated at 45% without additional water in the ger mination medium. There was no significant effect of light or temperature (2 5, 30 or 20/30 degrees C) on standard germination. Seeds showed the best ge rmination with Iml of water added to the germination medium in petri dishes . For standard germination testing, pawpaw seeds should be stratified for 1 00 days at 5 degrees C followed by germination in rolled towels at constant 25 or alternating 20/30 degrees C. Light was not required and final germin ation counts should be after 5 weeks.