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.