DIVERGENT SELECTION FOR BODY-WEIGHT AND YOLK PRECURSOR IN COTURNIX-COTURNIX-JAPONICA .11. CORRELATED RESPONSES OVER 30 GENERATIONS

Japanese quail lines were divergently selected for 4-wk BW (HW and LW lines) and plasma yolk precursor [total plasma phosphorus (TPP); HP an d LP lines] for 30 generations. The base population was a randombred c ontrol line (R1) that was maintained along with the selected lines. Su blines were established from the ninth selected generation of HW by co ntinuing to select males for increased 4-wk BW and selecting females f or increased (HW-HP line) or decreased (HW-LP line) TPP. Correlated re sponses over the entire selection period were measured. Egg production of HW, LW, HP, and HW-HP declined over generations. There was a posit ive quadratic component to the change in HW indicating that the change in egg production over generations was decreasing. There was no signi ficant change in egg production of LP. Number of ovarian follicles in rapid development increased in LP and decreased in LW and HP, Total fo llicular weight increased in HW and LP and decreased in LW. Production of abnormal eggs increased over generations in HW and HW-HP. Body wei ght at the beginning and end of the laying period increased in HW, HW- HP, HW-LP, and LP and decreased in LW. Egg weight increased in HW and HW-HP and decreased in LW and LP. The increase in egg weight of HW was due to a disproportionate increase in shell and yolk. Wet weight of t he liver increased in HW and decreased in LW and HP. Dry liver weight decreased in LW, HP, and LP. Mortality to 4 wk of age increased in LW, HP, and LP.