The changes in genetic parameters for various economic traits were studied in a White Leghorn population under long teon selection for egg number over 12 generations. The egg number, age at first egg and 20 week body weight showed higher heritability in base generation. TIle heritability declined considerably for egg number and age at first egg in later part of selection, which may be a consequence of high direct correlated response to selectioh in these traits, respectively. However, the heritability for egg weight and 20 week body weight were moderate to high in these periods of selection. The egg number showed negative phenotypic as well as genetic correlation with egg weight and age at first egg in different periods of selection, while it showed positive and moderate phenotypic and genetic correlation with 20 week body weight. These correlations showed wide fluctuation and did not present any consistent trend over different periods of selection.
White Leghorn, genetic parameters, selection
