January 2014 issue of the Cornell Flower Bulb Research Program Research Newsletter:
Over the last few years, we have been experimenting with the idea of applying ethylene-releasing plant growth regulators (PGRs) to the rootzone as a substrate drench. This is a rather radical idea for floriculture production overall and flowerbulb forcing in particular. In this newsletter, we’ll review ethylene as a growth regulator, discuss the commercially available ethylene-releasing PGRs and show a number of examples of such drenches on daffodil and hyacinth.