Estimates of Additive Genetic Effects, Maternal Genetic Effects, Individual Heterosis, Maternal Heterosis, and Egg Cytoplasmic Effects for Growth in <i>Tilapia nilotica</i>

Abstract

Abstract Lengths and weights of Auburn University‐Egypt and Auburn University‐Ivory Coast strains of Tilapia nilotica and their F 1 F 2 , and backcross hybrids were analyzed by multiple regression to estimate strain additive genetic effects, strain maternal genetic effects, individual heterosis (specific combining ability), maternal heterosis, and strain egg cytoplasmic effects for growth to determine why heterosis of the F 2 and backcross hybrids was greater than that of the F I hybrids. Individual heterosis and maternal heterosis made the greatest contributions to growth. The F 2 and backcross hybrids were larger than the F 1 hybrids because of maternal heterosis. Regression coefficients were used to predict growth for any possible hybrid combination. Egypt ♀× Ivory Coast ♂ F I hybrid females backcrossed to Egypt males and Egypt ♀× Ivory Coast ♂ F 2 hybrids were the largest groups evaluated in this study and were also predicted to have faster growth rates than any other possible Egypt‐Ivory Coast hybrid.