Abstract
Germination in response to gibberellic acid was used as an assay for wild oat seed dormancy. In growth chamber studies removal of glumes, a 5 °C reduction in night temperature (20 °C day/15 °C night vs. constant 20 °C), and a shorter photoperiod (12 vs. 18 h) during the period following panicle emergence reduced subsequent germination (increased dormancy) of mature seeds. Dormancy of field-grown wild oat seeds increased with increasing seed maturity and was affected by planting location and associated crop.