Identifying traits enabling turfgrass crown resistance to freezing damage

By Maicy Vossen

This article was originally published on the WinterTurf project blog.

Crown viability is key to survival of turfgrass after exposure to freezing temperatures. Previous research in the Sadok Lab at the University of Minnesota has shown that winter barley genotypes with smaller xylem vessels are more freeze tolerant than genotypes with larger xylem vessels [1]. At freezing temperatures, the smaller xylem vessel size prevents cells from breaking open. In the crown, having smaller xylem vessels could lead to less damage during freezing temperatures, leading to decreased loss of viability through winter.

Ultimately, the goal of our research is to develop a high-throughput vascular phenotyping method that can be used to determine freeze tolerance in turfgrass. This method will not require a freezing treatment and will be attainable through imaging of the xylem vessels. The beginning of this project is focusing on screening a population of 100 perennial ryegrass accessions for traits that enable one plant to be more freeze tolerant than another (Figure 1). These accessions are diverse in xylem vessel size. Screening will be accomplished through characterization of the plant micro-climate and environment in the field before and during winter, recording winter survival and phenotyping.

Turfgrass field research plots with perennial ryegrass in spaced plantings
Figure 1. Perennial ryegrass plot in St. Paul, MN containing 100 accessions being used for current data collection. Image taken October 2022.

This project began in the summer of 2022. Before the first substantial snowfall and freezing temperatures, measurements were taken to understand how much photosynthetic stress the perennial ryegrass accessions were under leading up to winter. After the snow melts in the spring and the plants begin to grow again, survival of the accessions will be recorded. This data will be analyzed to find traits that are related to winter survival in perennial ryegrass. Eventually, these traits will be used to breed improved cultivars of perennial ryegrass that better tolerate winter stresses.

The project "WinterTurf: A holistic approach to understanding the mechanisms and mitigating the effects of winter stress on turfgrasses in northern climates" is supported by the USDA National Institute of Food and Agriculture under the Specialty Crop Research Initiative program.


[1] Tamang, B., Lopez, J., McCoy, E., Haaning, A., Sallam, A., Steffenson, B., Muehlbauer, G., Smith, K., & Sadok, W. (n.d.). Association between xylem vasculature size and freezing survival in winter barley. Journal of Agronomy and Crop Science, 2022(208), 362–371.