Pasakinskiene, 1996;Thomas and Humphreys, 1991) while the ryegrass parent contributes rapid establish-Festulolium [Festulolium loliaceum (Hudson) P.V. Fournier] is a ment and forage quality (Casler, 1990; Thomas and hybrid between meadow fescue (Festuca pratensis Huds.) and Italian ryegrass (Lolium multiflorum Lam.) or perennial ryegrass (L. perenne Humphreys, 1991) to the hybrids. Forage quality of fes-L.). The ryegrass parentage gives festulolium cultivars marginal win-tulolium cultivars is similar to that of ryegrass cultivars terhardiness in regions with severely cold winters. The objective of (Casler, 1990), which is higher than for any other agrothis research was to determine if natural selection for field survival nomically important cool-season forage grass (Jung et resulted in a genetic improvement in freezing tolerance, forage yield, al., 1996). or persistence in northcentral and northeastern USA environments. On the negative side, the ryegrass parent generally The component strains of 'Spring Green' festulolium were compared reduces winter survival of festulolium hybrids and their with their unselected parents in a controlled-environment freezing derivatives. The lack of adaptation of festulolium and test. The component strains of Spring Green had 186% greater plant other ryegrasses (Lolium spp.) to the northcentral and survival and 34% greater tiller survival than their unselected parents. northeastern USA and southern Canada severely limitsSpring Green was compared with its two commercially available parents in a 13-location field test. Spring Green averaged 5.0% higher Published in Crop Sci

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