The effects of temperature and daylength on ̄ower initiation and development in Dianthus allwoodii and Dianthus alpinus

In four experiments the major effect on ̄owering was that of temperature. Temperatures applied between 2 October and 20 February in ̄uenced the time of ̄owering of D. allwoodii, `Doris', while in D. alpinus, `Pike's Pink', temperatures applied over a longer period between 2 October and 11 March in ̄uenced the time of ̄owering. Keeping stock plants at low temperatures, before cuttings were taken, advanced ̄owering. The earliest ̄owering in `Doris' was achieved by storing stock plants at 3.98C and then rooting cuttings at 14.98C (rather than at 10.08C) suggesting that it was possible to satisfy their ̄ower induction requirement entirely during cold storage. In `Pike's Pink' earliest ̄owering was achieved by storing stock plants at 3.98C and then rooting cuttings at 10.08C, suggesting that the cold requirement for ̄ower induction was not entirely satis®ed by cold storing stock plants but in addition needed some time at low temperature during rooting. The cold requirement of `Pike's Pink' was greater than that of `Doris' and in several treatments was not satis®ed suf®ciently for ̄owering to occur. The number of ̄owers in `Doris' was increased by low stock plant temperatures, low temperatures post-rooting, and higher temperatures during growing on. In `Pike's Pink' number of ̄owers were increased by low stock plant temperatures and low temperatures post-rooting. # 2000 Elsevier Science B.V. All rights reserved.