Genetic Studies on Poultry

The present study was carried out for seven seasons, from 1978 to 1984 at the Poultry Research Center of theAlexandria University, Faculty of Agriculture. The main objectives were: to measure the effects of individualselection in divergent directions for body weight at eight-weeks of age, to determine the influence of divergent selection for eight-week body weight on age and weight at sexual maturity and 90 day egg number and to provide esti-mates of the heritability of eight-week body weight, age and weight at sexual maturity and 90 day egg number.The experimental flock used consisted of two selected lines. In the 1971 season, the two lines initiated fromAlexandria chickens one of them is high line (HL) was sele- cted for high eight-week body weight, while the other lowline (LL) was selected for low eight-week body weight.Since then, selection continued for the following six seasons In the 1978 season, each line was differentiatedinto different families. The selection was continued on the same basis till now. Since 1978, from 15 to 22 indi v-idual breeding pens have been used to produce the chickens of high and low lines each year. Each pen had six to nine pullets mated with a single cockerl of the same line.A control line was obtained in each of the two seasons 1983 and 1984, by random cho d c e from all available birds of the two