International Perennial Wheat Genotype x Environment Trial; Observations from Minnesota.

Compared with annual crop species, perennials retain higher soil fertility, prevent loss of N and P through surface runoff, protect against soil erosion and are more resilient to pathogens and abiotic stresses.  Despite many potential benefits, perennial wheat survival is variable in different environments.  To test the survival of the current germplasm we are collaborating on a study coordinated by the New South Wales Department of Primary Industries, Wagga Wagga, Australia. Thirteen wheat (annual Triticum spp.) x wheatgrass (perennial Thinopyrum spp.) derivatives were grown at over 15 sites across 8 countries including one site planted in St. Paul, MN in September 2012 in 1 m rows with 0.5 m spacing, in three replications. Checks included T. aestivum, Th. intermedium, and Secale montanum. Eight out of 13 perennial wheat entries survived the first winter and produced seed, however only four entries survived across all three replications.   All perennial grass controls survived the first winter (2012/2013) and produced seed.  Following seed production, 7 of 8 perennial wheat entries regrew in the fall of 2013, indicating winter survival is important in Minnesota. In the second growing season, six of the seven regrowing lines survived the winter (2013/2014). The majority of the surviving lines (4/6) were derived from crosses between wheat and Th. elongatum (2n=2x=14); the remaining two surviving lines were derived from crosses to Th. intermedium (2n=6x=42). Unlike the more robust perennial grass controls, perennial wheat plots surviving for two growing seasons experienced high within-plot mortality. This observation indicates that improved germplasm may be needed for a viable two-year grain crop in Minnesota. By comparing our observations with other locations, we hope to identify environmental factors contributing to survival.