Stay-green compared with non-stay-green Lolium perenne in field swards with different cutting and nitrogen treatments

The purpose of this study was to investigate the effect of the stay‐green trait, originally introduced into perennial ryegrass (Lolium perenne) for amenity purposes, in field swards of stay‐green forage perennial ryegrass managed in different ways for agricultural use. The experimental treatments comprised all 18 combinations of two grass selections (stay‐green and non‐stay‐green), three intervals between cuts and three N treatments. The conclusions were that the introduction of the stay‐green trait (1) may not always confer greater greenness in the early life of a sward; (2) may confer greater greenness during leaf senescence more because carotenoids are unmasked to a lesser extent than because of a reduction in the length of leaf visibly senescing; (3) may reduce herbage yield, particularly when a long interval is allowed between defoliations; (4) may reduce the decline in the concentration of N in herbage during the latter part of a long period of regrowth; (5) may reduce the concentration of Na in herbage.