Estimates of Heritability and Correlations of Economic Traits in Two Strains of White Leghorn

Indian White Leghorn N strain (IWN) and Indian White Leghorn P strain IWP are the two strains of White Leghorn maintained at All India Co-ordinated Research Project (AICRP) on Poultry, Kerala Agricultural University (KAU), Mannuthy centre. The data of 20th generation on age at first egg or Age at Sexual Maturity (ASM), 16 and 40 week body weight (Bw16, Bw40), 28 and 40 week egg weight (Ew 28, Ew40) and egg production up to 40 weeks age (En40) pertaining to 2120 and 2112 of IWN and IWP strains of White Leghorn progeny belonging to 50 sires and 300 dam formed the basis of this study. The mean values of IWN strain for average Age at Sexual Maturity (ASM), 16 & 40 week body weight (Bw 16, Bw40), 28 & 40 week egg weight (Ew28 & Ew40) and En40 & En64 were 143.85 days, 1.116 kg & 1.584 kg, 50.63 g & 54.26 g and 115.99 & 237.13 respectively. The mean values of IWP strain for average age at first egg (ASM), 16 & 40 week body weight (Bw 16, Bw40), 28 & 40 week egg weight (Ew 28 & Ew 40) and En40 & En64 were 137.55 days, 1.131 kg & 1.651 kg, 50.42 g & 54.01g and 121.21 & 246.40, respectively. The production performance of IWP strain is numerically more than IWN strain in-terms of egg production but the egg weight of IWN is higher than IWP, indicates that the egg production and egg weight are negatively correlated. For both the strains, heritability of ASM, egg weight and egg production was low to moderate. Higher heritability was recorded for body weight characters. Positive correlation was observed between both egg weight characters on genetic and phenotypic scale as well as between body weight characters. Negative correlation was noticed between ASM and En40 as well as Egg weight and Egg production traits on both genetic and phenotypic scale.