Index selection for genetic improvement of some economic traits in layer chickens
MAROOF AHMAD, HARPAL SINGH AND R.K. SHARMA
Department of Genetics and Animal Breeding,College of Veterinary and Animal Sciences
G. B. Pant University of Agriculture & Technology
Pantnagar - 263 145 Uttaranchal
Data on 559 White Leghorn pullets progenies of 58 sires and 149 dams produced in single hatch were used for construction of selection indices in various combinations of age at sexual maturity (X 1), egg production (X 2), egg weight (X 3), 12-week body weight (X 4) and 36-week body weight (X 5). The heritability estimates of above five traits computed from sire component of variance were 0.16 ± 0.14, 0.29 ± 0.15, 0.08 ± 0.15, 0.34 ± 0.17 and 0.34 ± 0.18, respectively. A total of twenty-six selection indices were developed. On the basis of r IH (0.74) and r H (180.5 units) values, the index I 1, involving all the five traits was found to be most efficient. The reduction in r H values due to exclusion of different traits revealed that 36-week body weight (X 5) was most important trait followed by 12-week body weight (X 4), egg production (X 2), age at sexual maturity (X 1) and egg weight (X 3) for use of selection index for genetic improvement in White Leghorns.