Monday, November 13, 2006 - 2:00 PM

Cold stress studies of wild perennial ryegrass germplasm.

Brent Hulke1, Eric Watkins2, Nancy Ehlke1, and Donald L. Wyse3. (1) University of Minnesota, 411 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108, (2) Dept. of Horticultural Science, "1970 Folwell Ave., 305 Alderman Hl", "1970 Folwell Ave., 305 Alderman Hl", St. Paul, MN 55108, United States of America, (3) Department of Agronomy and Plant Genetics, University of Minnesota, 411 Borlaug Hall, 1991 Upper Buford Circle, St. Paul, MN 55108

The lack of winterhardiness of some cool season grasses limit their usefulness in northern climates.  Perennial ryegrass is one species which lacks good winterhardiness in northern climates, but has desirable qualities, such as wear tolerance and rapid establishment.  This species is also being grown as a seed production crop in Minnesota.  Since 2004, turfgrass researchers at the University of Minnesota have been attempting to find valuable wild germplasm to improve the tolerance of perennial ryegrass to northern winters.  The screening process has involved both direct, non-repeatable field studies and indirect, repeatable laboratory freezing tolerance studies.  Data from the 2004-2005 field season, which included a winter characterized by little snow cover and wide fluctuation in temperature, indicated that only 7 of 300 accessions studied had better winterhardiness than the most winterhardy check variety, NK200.  Accessions were subdivided into three groups based on this data, and seven accessions from each group were subjected to freezing tolerance tests in the laboratory.  Plants that survived the first winter were also subjected to the winter of 2005-2006 to further test winterhardiness in the field.  The data suggest that significant variability exists for cold tolerance in wild perennial ryegrass germplasm.