Abstract
Two kinds of genotype-environment interactions were estimatecl in Barred Plymouth Rocks. Variances attributable to sire family-location interaction were of no importance either for egg production or days to sexual maturity. On the other hand, comparison of sire families under different hatching periods supports the contention that the genotype for hen-housed egg production within one hatching period can not be identified with that within another. Statistical analysis showed that the variance due to interaction was highly significant for egg production, while it was not significant for sexual maturity. Implications of this phenomenon and discussions with regard to current poultry breeding techniques are also presented.
