Just posted: May 2019 issue of the Cornell Flower Bulb Research Program Research Newsletter:
Ethylene sensitivity of tulip cultivars: Some are resistant to ethylene!
This newsletter presents the latest word on ethylene sensitivity of tulip cultivars (current as of May 2019). Over 10 years, our research has indicated that about 20% of the 160+ tulip cultivars tested so far are substantially resistant to ethylene (as tested in the October/November time frame). These results are especially useful for exporters, USA warehouses, and also for tulip breeders.