Flowering Induced on Young Loblolly Pine Grafts by Out-of-Phase Dormancy

Abstract

Loblolly pine trees 3 to 7 years old grown in a heated greenhouse under a 20-hour photoperiod had quiescent buds induced by lowering the temperature and shortening the photoperiod. This treatment resulted in the formation of both male and female strobili. Overall, 38 percent of the ramets produced females, and 68 percent produced males. There was no significant difference in the frequency of flowering among 3-, 5-, and 7-year-old scions.