Freezing Tolerance of Creeping Bentgrass Cultivars.

Creeping bentgrass (Agrostis stolonifera) has been known to have a high degree of freezing tolerance. This freezing tolerance and superior ability to provide a high quality putting surface has made creeping bentgrass the top choice for putting greens throughout the northern United States. Plant breeders have developed many cultivars that possess valuable traits such as high turfgrass quality, increased turf density, dollar spot resistance, and heat tolerance. In recent years, there have been reports of creeping bentgrass death due to extreme cold temperatures in parts of the northern United States. Because recent breeding efforts have not focused on this trait, it may be possible that some newer cultivars lack the freezing tolerance necessary to survive extreme low temperatures. The objective of this experiment was to evaluate the freezing tolerance of a range of creeping bentgrass cultivars developed over the past six decades. Five creeping bentgrass cultivars (Penncross, L-93, 007, Penn A-4, T-1 ) were evaluated. Individual cultivars were seeded into 72 cell flats and allowed to develop in the greenhouse prior to freezing treatment. Plants were acclimated for 2 weeks at 3⁰C in a growth chamber and then subjected to ten difference temperatures ranging from -10 to -28⁰C using a programmable freezer. After freezing, plants were returned to the growth chamber at 3⁰C for 48 hours to thaw before being returned to the greenhouse. Whole plant survival and lethal-temperature 50 was determined from each cultivar. Results have showed significant differences in freezing tolerance between the 5 widely-used cultivars cultivars used in this trial providing initial insight on freezing tolerance of creeping bentgrass cultivars. Results and implications of this work will be discussed.