Relationship between Contents of Chlorophyll (a+b) (SPAD values) and Nitrogen of Some Temperate Grasses

In a field experiment the chlorophyll (a+b) (SPAD readings) and nitrogen contents of three grass species (Festuca arundinacea Schreb., Lolium perenne L., and Lolium multiflorum Lam.) and three intergeneric hybrids of Festuca pratensis Huds. × Lolium multiflorum Lam. and Festuca arundinacea Schreb. × Lolium multiflorum Lam. were measured. Close relationships were found between SPAD readings and nitrogen leaf content (r 2 = 0.873** 0.491** and 0.938**) for the 1st, 2nd, and 3rd cut, respectively. SPAD readings and N contents were closely correlated (r = 0.836**) confirming that SPAD measurements could be used in grass selection and/or breeding for high N concentration in herbage.