Effects of gibberellic acid and dormancy-breaking chemicals on flower development of Rhododendron pulchrum Sweet and R. scabrum Don
Journal
Scientia Horticulturae
Journal Volume
83
Journal Issue
3-4
Pages
331-337
Date Issued
2000
Author(s)
Sung, F.-H.
Abstract
Flower bud dormancy is a restriction in regulating the azalea flowering period. Although many studies have been conducted on ending dormancy by cold temperature and GA treatment, little information is available on the effects of dormancy-breaking chemicals on terminating azalea flower bud dormancy. The purpose of this study was to determine whether dormancy-breaking chemicals affect the termination of flower bud dormancy and precipitate anthesis. Three-year-old pot-grown plants of Rhododendron pulchrum were sprayed with dormancy-breaking chemicals: 500 ppm GA3, 0.245% cyanamide, 8% mineral oil, 2% potassium nitrate, and 0.5% thiourea on 31 December 1995. The results showed that GA3 and thiourea brought on flower bud anthesis. Five-year-old pot-grown plants of R. scabrum were sprayed with similar dormancy-breaking chemicals on 23 December 1997 and exhibited the same results. In addition, potassium nitrate did not hasten flower bud anthesis, but it increased flower diameter. The results suggest that thiourea may be used to regulate the azalea flowering period. (C) 2000 Elsevier Science B.V.
Type
journal article