GENETIC-ANALYSIS OF EGG-SHELL QUALITY CHARACTERS IN LAYER CHICKEN

Data were collected on 4538 pullers of 2 strains (PL 1 and PL 2) for v arious measures of shell-quality. Strain PL2 had higher production bod y weight and better shell-qualify. Sex linked genetic effects appeared to be important in most of the shell-quality characters. The pooled s ire-component heritabilities (%) for PL 1 and PL 2, respectively, were : 39+/-9 and 49+/-11 for shell thickness; 45+/-10 and 40+/-10 for spec ific gravity; 40+/-9 and 31+/-8 for % shell; and 43+/-10 and 27+/-8 fo r egg weight Egg weight had positive genetic correlations with the oth er measures of shell quality. The genetic correlations among the vario us measures of shell quality were all greater than 0.89 and as high as unity.