Inheritance and association among various economic traits of two strains of White Leghorn

The present study was conducted in IWN and IWP strains of White Leghorn maintained under A.I.C.R.P on poultry improvement, at Poultry Complex, College of Veterinary Science Anand Agricultural University, Anand. The data on age at first egg (AFE), body weight at 16 (BW16), 40 (BW40), and 64 (BW64) weeks, egg number produced upto 40 (EN40) and 64 (EN64) weeks of age and egg weight at 28 (EW28), 40 (EW40) and 64 (EW64) weeks of age of1867 and 1825 pullets of S₁₁generation each of IWN and IWP strains respectively were utilized. IWN strain showed significantly (P<0.05) higher egg production upto 40 (EN40) and 64 (EN64) weeks of age as compared to IWP strain in spite of non significant differences in age at first egg. The BW16, BW40, BW64, EW28, EW40and EW64 were significantly (P<0.05) higher in IWP strain as compared to IWN strain. The estimate of heritability for AFE was moderate (0.214±0.069) in IWN strain and low (0.100±0.056)in IWP strain. Estimates of heritability for BW16 and BW40 were high in IWN and low in IWP strain. EN40 and EN64 showed low estimates of heritability in both the strains. The genetic correlation of AFE with BW16 was low and negative in both the strains where as it is positive and high with BW40and BW64in IWN strain. The genetic correlation of AFE with EN40 and EN64 were negative and high in IWN strain. The genetic correlation of AFE with EW28 was negative and low in both strains whereas with EW40 it was positive but low in IWN strain and high in IWP strain. The genetic correlation of AFE with EW64was negative and high in IWN strain. The genetic correlation of EN64 and EN40was found to be high in both the strains but positive in IWN and negative in IWP strain and same with EW were found to be high but negative EW28 and EW40 and positive with EW64 in IWN strain whereas positive and low with EW28 in IWP strain. Low estimates of heritability were observed in almost all the traits in both the strains except age at first egg, body weight 16 and body weight in IWN strain in which they were high. Low estimate indicated that the non additive genetic variance has played a greater role in governing these traits while high estimates indicated that additive genetic variance has played a greater role in governing the traits. Genetic correlation among the traits in both the strains showed no definite trend.