Phenotypic and genetic parameters of economic traits in IWH and IWI strains of White Leghorn under selection

Abstract

Genetic and Phenotypic parameters were studied in various economic traits in IWH and IWI strains of White Leghorn. The heritability of average age at sexual maturity and egg production up to 40 and 64 weeks of age was observed to be of low to moderate in magnitude, while no definite trend of gene effects was observed for age at sexual maturity and egg production up to 64 weeks of age in both the strains. For egg production up to 40 weeks of age additive and sex-linked gene effects were found to be important in IWI strain. Most of the estimates of genetic correlation estimated from sire component of co-variance were higher than the dam
component of covariance, which were also inconsistent in direction in various strains. The egg production up to 64 weeks of age has got positive genetic association with body weight at various ages (16, 40 and 64 week) in both the strains and negative genetic association with age at sexual maturity in IWI. Association of egg production up to 64 weeks of age with egg weight at various ages varies from very low to very high in magnitude, which were positive in IWH strain, while no definite trend regarding direction of association was observed in IWI strain. General trend of association of egg production up to 64 weeks of age with egg production up to 40 week was positive and high in both the strains under study.