Abstract
The objective of this study was to obtain information about the adaptability of Italian ryegrass (IR), Westerwolds ryegrass (WWR) and festulolium to the Tohoku region. Fourteen cultivars of the three grass species introduced from north and east European countries were tested in autumn and spring transplantation experiments. All WWR cultivars had high spring habit (greater than 31.1%) and low adaptability to winter of the Tohoku region. In the spring transplantation experiment, regrowth vigor after summer was negatively correlated with spring habit. However, "Limella", characterized as having higher spring habit, showed good regrowth vigor and had a pattern that was entirely distinct from the other WWR cultivars in both experiments. All foreign IR cultivars showed later maturity than Japanese mid-maturity cultivar "Nagaha-hikari" and no spring habit. "Fredrik" showed the best snow survival but less than optimal spring growth vigor. These characteristics suggest that "Fredrik" partly consists of hereditary determinants derived from species other than IR. Festulolium cultivars had high adaptability to winter and their regrowth after summer was the best among the three species. In particular, "Sulino" showed the highest regrowth vigor and also showed crown rust resistance.
