Colour evaluation of Poa pratensis cultivars

The colour of 30 cultivars is described using visual scores, a colorimeter generating 'L' (light-dark), 'a' (green-red) and 'b' (yellow-blue) parameters, a reflectance ratio (near infra red:red) meter and a chlorophyll extraction procedure. A combination of 'L' and 'b' values gave the closest correlation with visual colour score but neither parameter was associated with visual merit score. Reflectance ratios of both field plots and clippings were significantly correlated with visual colour, merit and colorimeter 'a' values. Of the objective techniques used, it was concluded that the colorimeter gave the best qualitative description of colour but the reflectance ratio was useful in giving quantitative information on intensity of greenness.