A comparison, under controlled environmental conditions, of a Lolium multiflorum selection bred for high dry‐matter content and non‐structural carbohydrate concentration with a commercial cultivar

The nutritional value of Italian ryegrass (Lolium multiflorum) selection 121, bred for a high dry-matter content and a high concentration of total non-structural carbohydrate (TNC), was compared with that of Westerwolds ryegrass (L. multiflorum ssp. Westerwoldicum) cv. Midmar in a controlled environment. The concentration of neutral-detergent fibre (NDF), acid-detergent fibre (ADF), acid-detergent lignin (ADL), nitrogenous compounds, minerals and in vitro digestibility were investigated as characteristics of nutritive value. The anatomical features of selection 121 and the Midmar cultivar were studied to determine possible structural differences. Thirty pots each of selection 121 and Midmar containing four plants per pot were arranged in a randomized block design in a controlled environment chamber. There were two temperature regimes during the study, the first being a warm regime (30 °C/20 °C) for 7 weeks followed by a cold regime(20 °C/7 °C) of a further 7 weeks. In the warm regime, the dry-matter (DM) content and the TNC concentration of selection 121 were 0·17 and 0·16 higher, respectively, than Midmar. The NDF concentration was significantly (P < 0·01) higher in Midmar than in selection 121. When grown under warm conditions, Midmar had significantly (P < 0·001) higher concentrations of Mg, K, Na and Mn than selection 121. In the cold regime, the DM content and TNC concentration of selection 121 were 0·25 and 0·22 higher, respectively, than Midmar. No significant differences in the anti-quality factors investigated were found between the two ryegrasses. In the cold regime, Midmar had significantly (P < 0·001 and P < 0·01) higher Ca, Mg, K, Na, Zn, Mn and P concentrations than selection 121. The results from this controlled environment study suggest that selection 121 is superior to Midmar in terms of the quality characteristics DM and TNC, and that these characteristics are not positively linked to anti-quality factors associated with forage species.