Seed Germination of Two Populations of Rhododendron vaseyi: Influence of Light and Temperature

Abstract Seeds of two populations of Rhododendron vaseyi A. Gray (pinkshell azalea) were germinated at 25C (77F) or an 8/16 hr thermoperiod of 30/20C (86/68F) with daily photoperiods at each temperature of 0 (total darkness), ½, 1, 2, 4, 8, 12, or 24 hr. Germination was recorded every 3 days for 30 days. Light was required for germination regardless of population or temperature. As photoperiod increased, germination increased. The highest cumulative (30-day) germination percentages were realized at 30/20C with a 24-hr photoperiod; germination percentages for populations 1 and 2 were 45 and 50%, respectively. Temperature and photoperiod requirements for germination did not generally differ between the two populations.