Genetic analysis of body weight in a selected line of Rhode Island Red grower chicken

A total of 1207 pedigreed progenies of 50 sires and 177 dams of a selected line of Rhode Island Red chicken were investigated in two hatches at ICAR-Central Avian Research Institute for genetic analysis of their body weights. The genetic and non-genetic parameters of chick weight at day-old age and body weight at different ages were estimated using least squares analysis of variance. The heritability and correlation coefficients were estimated for different traits using paternal half-sibs. The mean sum of squares for sex component of variance was significant for body weights at third week of age onwards, males being heavier throughout the ages. Sire component of variance was also significant for chick weight and different body weights except the estimates at 6th and 16th week of age. Hatch component of variance was highly significant for chick weight and body weights upto 12th week of age. Regression effect of chick weight on subsequent body weights was found significant specifically for body weights from 1st week onwards to 20th week of age. The heritability estimates were 0.775 +/- 0.151 for chick weight, 0.303 +/- 0.09 to 0.44 +/- 0.142 for body weights from 1st week to 12th week of age, and 0.258 to 0.248 for body weights from 16th week to 20th week of age. The estimates at lower age could be used in selection programme based on the flock's own performance to improve those traits. The genetic and phenotypic correlation coefficients were positive and highly significant in most of the cases. The corresponding estimates ranged from 0.044 to 0.990 and 0.020 to 0.788, and these coefficients could be combined in construct of standard selection indices for optimum growth in body weight that might be adopted in future breeding strategy for this RIR chicken genotype.