Abstract

Seeds from two provenances (Wayne Co., NC, and Escambia Co., AL) of Atlantic white-cedar [Chamaecyparis thyoides (L.) B.S.P.] were stratified (moist-prechilled) for 0, 30, 60 or 90 days at 4C (39F). Following stratification, seeds were germinated at 25C (77F) or 8/16 hr thermoperiods of 25/15C (77/59F) or 30/20C (86/68F) with daily photoperiods at each temperature of total darkness, ½, 1,2, 4, 8, 12, or 24 hr. Seed germination of the Alabama provenance was greater than the North Carolina provenance for all treatments. There were no significant differences in percentage germination between 25/15C (77/59F) and 30/20C (86/68F) for any durations of stratification for either provenance. Regardless of stratification, germination was lowest at 25C (77F) for both provenances. When nonstratified seeds from the North Carolina provenance were germinated at photoperiods ≤ 12 hr, total germination never exceeded 5%, indicating an obligate light requirement. On the other hand, an obligate light requirement was not observed for seeds from the Alabama provenance since 15% of the nonstratified seeds germinated in darkness. However, for both provenances, stratification and daily photoperiods ≥ ½ hr greatly increased germination. The North Carolina provenance required 90 days stratification to maximize germination (66%), whereas the Alabama provenance needed only 30 days (80%). High germination percentages were due, in part, to rigorous seed cleaning.