By Maicy Vossen
This article was originally published on the WinterTurf project blog.
An update to Assessing freezing damage in perennial ryegrass.
Breeding of winter hardy perennial ryegrass cultivars is making slow progress. To advance our current understanding of which factors impact winter hardiness, we are collecting data on perennial ryegrass planted in environmentally unique locations. As a part of the WinterTurf project, a population of 100 perennial ryegrass accessions with diverse genetic backgrounds was planted in three locations: St. Paul, Minnesota; Amherst, Massachusetts; and Landvik, Norway.
Figure 1 shows the average air temperatures for winters in all three locations for last winter (2022-2023) and the current winter (2023-2024). Last winter, Landvik experienced the mildest temperatures, hovering around freezing. Amherst and St. Paul experienced more extreme low temperatures compared to Landvik. Further, the duration of these low temperatures was much longer in St. Paul than in Amherst. Last winter, few perennial ryegrass plants were damaged by winter stresses.
After a mild start to the winter, temperatures are currently well below freezing here in St. Paul, Minnesota, but how do the other locations compare? Amherst and Landvik haven’t experienced the -20oC temperatures that St. Paul has recently seen, but Landvik has already experienced some well below freezing temperatures within the last month, a change from the mild temperatures there last year. Amherst has been experiencing warmer winter temperatures this year, often staying above freezing. It is too soon to determine how this winter’s temperatures will damage perennial ryegrass plants.
We are only about 2 months into winter, so we could still see many changes in air temperature over the next several weeks. One key thing to note about the air temperatures, is that each location is experiencing different temperature patterns, averages, and durations of extreme low temperatures. This reveals the importance of having the perennial ryegrass accessions planted in these locations, creating more robust survival data for analysis. In addition, plants that show good survival at both locations over the two years of this trial can also be advanced in a plant breeding program leading to the development of winter hardy perennial ryegrass cultivars.
This project is supported by the U.S. Department of Agriculture, National Institute of Food and Agriculture, Specialty Crop Research Initiative under award number 2021-51181-35861.