Effects of Ethylene Inhibition on Creeping Bentgrass and Annual Bluegrass Survival of Ice Cover Stress.

Ice damage to annual bluegrass (Poa annua; ABG) and creeping bentgrass (Agrostis stolonifera; CBG) golf course putting greens is a significant problem in many parts of the world and climate change may increase ice incidence. ABG is more susceptible to necrosis (killed at approximately 45 to 70 day) and CBG is more tolerant (killed after 100+ day). Ethylene, a gaseous hormone, is known to play a role in regulating metabolic activity rates during dormancy. Differeing amount of ethylene are produced by CBG and ABG. Ethylene association with tolerance to various winterkill stresses, of cool-season turfgrasses has yet to be investigated. We hypothesize that high levels of ethylene production may have negative effects on ice stress survival and treatments that inhibit ethylene production may improve survival under ice stress. A field and growth chamber study was conducted in 2016 at the Hancock Turfgrass Research Center in East Lansing, MI which included treatments of an untreated control, ethephon as an ethylene application, ethylene precursor aminocyclopropane-1-carboxylic acid (ACC) as an ethylene application, aminoethoxyvinylglycine (AVG) to inhibit ethylene, and urea applications in a field and growth chamber experiment. In the first year of a two-year experiment, the ethephon treatments had lower visual turfgrass quality (TQ) and normalized difference vegetation index (NDVI) when compared to other treatments in ABG. Ethylene production was significantly higher in ethephon and ACC treated ABG when compared to other treatments. Both ABG and CBG respiration rates were increased due to ethephon treatment when compared to other treatments. After 20 days in a low temperature growth chamber, regrowth of ABG was decreased by ethephon treatment when compared to the untreated control. Applications of effective ethylene products appear to increase ethylene production and respiration while decreasing tolerance to survival from ice cover.