Genetic studies on some economic traits of Rhode Island Red

The data for the present study was taken from 776 pullets of a RIR strain which were produced hom 46 sires and 182 dams in 4 hatches and maintained by a commercial poultly breeding organization, Mean values, heritability estimates, genetic, phenotypic and environmental correlations were computed to evaluatc the performance, understand the economic traits and the nature of relationship among traits under study. The averages of 20-WKBW, ASM, 40-WKBW, EP and 35-WKEW were found as 1517.69±0.40 g, 149.18±0.41 days, 1783.43±0.73 g, 112.49±0.54 eggs and 50.82±0.13 g, respectively. The heritability estimates based on sire component of variance were 0.1 0±0.07 for 20-WKBW. 0.18±0.08 for ASM, 0.58±0.14 for 40-WKB W. 0.14±0.07 for EP and 0.56±0.14 for 35-WKEW. The genetic and phenotypic correlations of ASM with 40-WKBW and 35-WKEW were positive but negative and significant with EP. These correlations of 40-WKB W with EP were ncgativc but positive and signitlcant with EW. The EP was negatively correlated with EW at genetic and phenotypic levels. The results of the present study revealed that the egg production potential of RIR strain is at par with White Leghorns. The lower magnitude of heritability of egg production may be due to the continuous selection pressure applied for many generations. It was also indicated that birds with faster growth mature early and lay more eggs. Pullets laying more eggs would lay smaller eggs.