USE OF PHOTOMETRICALLY DETERMINED SHELL C OLOR PARAMETERS AS SELECTION CRITERIA FOR MARKETABLE BROWN-SHELLED EGGS

Based on data of five German random sample tests and pedigree data of a commercial breeding programme, different parameters of shell colour were investigated. In addition, a consumer survey was conducted to det ermine preferences for specific shell colour. The shell colour paramte rs L, a* und b*, electronically measured with a Minolta Chroma Meter, agreed well with subjective scores assigned by an experienced person before the measurements. Significant differences were found between st rains, whereas differences among stations were much smaller. Heritabil ities estimated from daughter-dam regressions and from site components of hierarchical analyses of variance were in the range of .3 to .5 an d reasonably consistent across lines, years, and methods of estimation . Genetic correlations between pure-line and cross-line shell colour, based on paternal half sisters in different environments, were very cl ose to unity, correlations with other traits were weak. The consumer s urvey indicated a preference fur intermediate shell colour and discrim ination against extremely dark shell as well as tinted shells.