THE EFFECTS ON GROWTH AND FLOWERING OF THE CHEMICAL GROWTH REGULATORS ETHEPHON ON NARCISSUS AND ANCYMIDOL ON TULIP

The effects of ethephon and ancymidol were studied on forced narcissus and tulip respectively. The chemicals were applied to the soil at a range of concentrations and at different stages in crop growth. The stem and leaf length of narcissus "Carlton" was effectively reduced by ethephon. However, in 1972 crop damage occurred at the greatest rate, 960 ppm ai, and at the earliest time of application, 10 cm stem height. Ethephon reduced stem and leaf length equally so that a balance between the two was maintained. Ancymidol reduced the stem length of tulip cv. "Paul Richter" much more than the leaf length and was only effective if applied when flower stems were 5–10 cm long. Low rates were as effective as high ones. Ancymidol did not cause flower damage.