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Aims: An Italian ryegrass cultivar (Lolium multiflorum Lam. cv. Bb2067), selected and bred for increased leaf magnesium (Mg) concentration in the 1970s, reduced the incidence of hypomagnesaemia in sheep under experimental grazings. Here, we report evidence from archival experiments showing that cv. Bb2067 had consistently greater Mg concentrations at multiple sites. We also aimed to quantify variation in leaf Mg concentration among modern perennial ryegrass (Lolium perenne L.), hybrid ryegrass (Lolium perenne × multiflorum), and tall fescue (Festuca arundinacea Shreb.) cultivars. Methods: Data are reported from unpublished 1980s field-plot experiments for cv. Bb2067 and contemporaneous reference cultivars, sown at two UK locations in 1983 and 1984, and from 397 cultivars of modern forage grass in 13 UK-based breeding experiments sampled in spring 2013. Results: Across sites, years and cuts, cv. Bb2067 had a consistently greater leaf Mg concentration and lower potassium (K) concentration and forage tetany index (FTI) than reference cultivars in the 1980s experiments. Seasonal variation in leaf Mg and K concentrations and FTI were observed in the 1980s experiments, with K concentrations being generally greatest and Mg concentrations smallest in spring. Among modern forage grasses, there was large variation in leaf Mg concentration (up to 6.3-fold) and FTI (up to 2.1-fold), both within and between species, which varied independently of yield. Among a subset of hybrid ryegrass cultivars, there is evidence that the high Mg trait is already present in some modern breeding lines, albeit previously unreported. Conclusions: The variation in leaf Mg concentration and FTI among old and new cultivars shows there is considerable potential to breed forages with improved mineral quality to improve livestock health, potentially without compromising yield or other nutritional traits. [ABSTRACT FROM AUTHOR]

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]