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Four grass species typically found in semi-natural pastures in the UK were sown individually in boxes (85 × 44 × 14 cm) to create micro-swards. Yorkshire fog ( Holcus lanatus L.); creeping bent ( Agrostis stolonifera L. cv Kromi); rough meadow-grass ( Poa trivialis L.); and perennial ryegrass ( Lolium perenne L. cv Glen) were offered to yearling Simmental × Holstein steers in short-term tests to characterize bite mass in relation to morphological traits of the grass species. Boxes were weighed (±0.1 g) before and after a 5 min period during which the steers were allowed to take ~50 bites. Perennial ryegrass had the greatest sward surface height (17.7 cm vs. mean 12.7 cm for the other species). Extended tiller length was greatest for ryegrass (17.3 cm) and least for rough meadow-grass (13.5 cm). Leaf length was greatest for ryegrass (6.5 cm) and Yorkshire fog (7.0 cm) and least for creeping bent (4.0 cm). Sward DM% was lowest for ryegrass (19.7%) and highest for creeping bent and rough meadow-grass (mean 23.2%). Number of bites taken from the boxes did not differ between grass species (mean 32.7 bites). Mean dry matter bite mass was greatest for perennial ryegrass (0.50 vs. mean 0.37 g DM bite−1 for the other species). Regression analyses indicated that the best sward variables for predicting mean DM bite mass were sward DM% ( F prob. = 0.066) and sward surface height ( F prob. = 0.086). While morphological characteristics affected bite mass, more is yet to be learned about other factors that may affect intake characteristics of forage species to improve economic and environmental sustainability. [ABSTRACT FROM AUTHOR]

Perennial (Lolium perenne L.) and annual (L. multiflorum) ryegrass are important species for landscape (e.g., turf) and agricultural (e.g., pasture systems) uses. Abiotic stresses limit the survival, growth, and/or appearance of these species. The synthesis and accumulation of quaternary ammonium compounds (QACs) such as glycinebetaine (GB) are an adaptive response to abiotic environmental stresses in some species. Both L. perenne and L. multiflorum are GB-accumulating species, and exogenous application of GB may enhance growth under less-than-optimal environmental conditions. We tested the effects of exogenous application of GB on growth and water relations of annual and perennial ryegrass growing under temperatures at the lower limits of their optimal growth. Osmotic stress resulted in increased GB accumulation in L. perenne, but exposure to cold temperatures did not result in increased GB accumulation in either species. Both species accumulated higher concentrations of GB in leaf and stem tissues when exogenous GB was supplied, regardless of growing temperature. Exogenous GB did contribute to lower osmotic potential in both species, but did not affect relative water content, although succulence was higher in some cases. Overall, exogenous GB did not affect growth under optimal growing temperatures, but did enhance growth of L. perenne growing under low temperatures. [ABSTRACT FROM AUTHOR]

Forage plants underpin the livestock industry. Selective breeding, including polyploidization, where genome size is increased by whole genome duplication, changes the productivity and stress tolerance of new varieties. We conducted a growth chamber experiment to investigate the likely responses of Lolium perenne L. to drought, testing four diploid and four tetraploid varieties. We simulated projected spring and summer temperatures for the South-West of England in 2080, applying three projected rainfall scenarios, which varied in drought severity. Drought caused a reduction in productivity, but there was substantial variation between varieties (up to 82%), with the optimal variety changing depending on drought severity. Across three harvests, productivity declined by 43% and 27% (dry biomass) for the severe and likely drought scenarios, respectively. In the final harvest, tetraploids exhibited a greater biomass under severe drought, whereas diploids had a greater biomass under the current rainfall and likely drought scenarios. Longer stomata were observed in tetraploids; however, stomatal conductance was not significantly different between ploidy levels. Trait selection will be important for future drought adaptation. Local climate projections will need to be consulted when selecting L. perenne varieties to tolerate the spatially variable reductions in future rainfall. [ABSTRACT FROM AUTHOR]