ESTIMATION OF COMBINING ABILITY IN EGG TYPE CHICKENS FROM A DIALLEL CROSS

Six single crosses and 6 reciprocal crosses were produced in the fashi on of a modified diallel using 4 White Leghorn strains. Sires (20) fro m each strain were mated with 20 dams from each of the other 3 strains simultaneously. General combining ability was more important compared to other measures ol: genetic variability in the inheritance of all t he traits considered except for egg weight. Specific combining ability appeared to be important only for body weight at 500 days of age and yolk index. Significant maternal effects were evident for egg producti on to 280 and 500 days of age, egg weight, yolk index and shell thickn ess. Sex-linked effects were important for body weight at 280 days of age, egg production to 260 and 280 days of age and average egg weight.