The measurement of leaf colour in grasses

SUMMARY A method of assessing colour of grass leaves was developed to distinguish between cultivars. Leaves from a representative population of 60 plants of each cultivar were measured. To eliminate subjective judgment a colour difference meter was used, giving tristimulus values X, Y and Z (approximating to red, green and blue respectively), from which the colour co-ordinates L, a and b of the Commission Internationale de L'Eclairage system were calculated. In a pilot study two visually distinguishable perennial ryegrass cultivars were easily separated (P <0·01) using the colour measurements. In a further examination comparing 23 cultivars, 68% of all possible cultivar pairs were separated (P <0·01).