Monitoring changes in genetic parameters for growth traits over generations of selection in local chickens in Egypt

Estimating the genetic parameters for growth traits is a crucial step before designing breeding programs to enhance the productivity in local chicken breeds. The current study estimated the genetic parameters of two local chicken lines selected for meat production (Normally Feathered, CE۱, and naked-neck, CE۳) and tracked the changes in these parameters over three generations of selection. Heritability estimates for the hatch weight were moderate, ranging between ۰.۳۰ and ۰.۳۱. Lower estimates ranged from ۰.۲۸ to ۰.۳۳, and were obtained for BW۲ and BW۴, respectively. The genetic correlations were moderate to high, and varied from ۰.۴۳ (BW۱۲ and BW۱۸) to ۰.۸۸ (initial BW and BW۲) in the seventh generation of selection. The values in the eighth generation had the same trend and varied from ۰.۴۱ (initial BW and BW۱۸) to ۰.۸۶ (BW۲ and BW۴). Similar values were obtained for body weight gain (BWG) and growth rate (GR) traits, where the highest genetic correlation (۰.۸۶) was between BWG (۰-۶) and GR (۰-۶) in the seventh and ninth generations, respectively, and the lowest was ۰.۶۲ that found between BWG (۶-۱۲) and GR (۱۲-۱۸) in the eighth generation. However, the highest phenotypic correlation (۰.۷۱) was also obtained between BWG (۰-۶) and GR (۰-۶) in the eighth generation, and the lowest value (۰.۴۲) was obtained between BWG (۶-۱۲) and GR (۱۲-۱۸) in the ninth generation of selection. The results suggested that there is enough genetic variation for further improvement in body weight at the juvenile stage.

کلیدواژه ها:

genetic correlation ، genetic parameters ، heritability ، local chicken ، phenotypic correlation ، selection