Forage potential of winter-hardy perennial ryegrass populations in monoculture and binary alfalfa mixture

Perennial ryegrass (Lolium perenne L.) is a cool-season grass valued for its grazing characteristics and nutritive value. MSP3984 and MSP4029, breeding populations selected for winter-hardiness, were evaluated for biomass and nutritive value in monoculture and grass–alfalfa mixtures (Medicago sativa L.). Plots were sampled at conventional hay harvest intervals at three Minnesota locations for two production years, 2017 and 2018. Persistence was evaluated in the spring of the 3rd year, 2019. MSP3984 and MSP4029 were compared to commercial cultivars of perennial ryegrass (Lolium perenne L.), meadow fescue (Festuca pratensis Huds.), tall fescue (F. arundinacea Schreb.), and orchardgrass (Dactylis glomerata L.). Location and year × location effects largely influenced grass monoculture yields (p <.001) and botanical composition of mixtures (p <.001). In general, perennial ryegrass monocultures yielded less and were less persistent (p <.05) compared to the other cool-season grasses. Biomass, nutritive value, and persistence did not differ among MSP3984, MSP4029, and the perennial ryegrass check ‘Remington’. However, MSP4029 was less competitive in grass–alfalfa mixtures than ‘Remington’ (p =.01). Perennial ryegrasses had lower neutral detergent fiber (NDF) concentrations than meadow fescue (p =.001) and orchardgrass (p <.001). Perennial ryegrasses also had lower acid detergent fiber (ADF) values on average than the other grasses, but cultivar effects were influenced by a year × location interaction (p =.02). This research reinforces (a) the importance of evaluating cool-season forage grasses across latitudinal and precipitation gradients, (b) the value of grass–legume mixtures for yield stability compared to monocultures across locations and production years, and (c) the sustained need to improve forage production and persistence of perennial ryegrass for cold environments.