Effects of selection for four week body weight on reproductive performance in Japanese quail

This research was carried out to determine the genetic effects of divergent selection under two different selection pressures for four week body weight over three generations on reproductive characteristics and some egg characteristics in Japanese quail. Birds were weighed individually. Individual selection for body weight was carried out at four weeks, separately for each sex. The proportion kept was 10% for males and 30% for females in 10Y and 10D lines, and 20% for males and 60% females in 20Y and 20D lines. 10Y and 20Y lines were selected for high body weight, 10D and 20D lines were selected for low body weight. Age at sexual maturity was not affected by lines and generations. Average age at sexual maturity was 46 days. Early death rates were decreased by selection. But mid term and late deaths were not affected by selection. Average early, mediavel and late embryonic mortalities were %7.99. %13.47 and %15.93 in Y lines and %7.25, %10.36 and %20.49 in D lines. There were not differences in fertility and hatchability among lines. Fertility was increased by selection. Hatchability did not change. Fertility hatchability of fertile eggs and hatchability of all eggs over generations were %79.82, %54.46 and %43.39 respectively All egg characteristics except shell weight per unit surface area were changed by selection. Egg weight, shape index, albumen index was affected by lines. Egg weight, albumen index and yolk index during the selection increased from 10.2A g to 11.45 g, from 11.56 to 14.03 and from 45.37 to 48.86 respectively. Yolk percentage and form index decreased from 33.83 to 32.22 and from 82.23 to 79.74 respectively. Average Haugh unit and shell weight per unit surface area over the generations were 95.21 and 40.39 mg/cm(2) respectively.