GENETIC ANALYSIS OF TWO STRAINS OF WHITE LEGHORN UNDER RECIPROCAL RECURRENT SELECTION PROGRAMME
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Date
2000
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AAU, Anand
Abstract
The present study was carried out to study the inheritance pattern in terms of magnitude of genetic, phenotypic variances and covariances for economic traits in the two strains and their reciprocal crosses (viz. IWD, IWK, DK and KD) under reciprocal recurrent selection (RRS) for five successive generations under All India Coordinated Research Project on Poultry (AICRP) at Poultry Complex, Gujarat Agricultural University, Anand Campus, Anand. Number of pullets from 1^^ to 5 generation under different genetic groups and crosses utilized as experimental materials were 879, 1551, 1395, 2080 and 1911. Over the generations, number of pullets utilized were 1819, 2048, 1650 and 2229 in IWD, IWK, DK and KD genetic groups respectively. The data obtained on these birds were analyzed to obtain the estimates of the means, heritability, genetic and phenotypic correlations and genetic correlation between crossbreds and purebreds for different economic traits. For computation of the estimates least squares analysis technique using LSMLMW and MIXED MODEL computer , programme (Harvey, 1990) was utilized. The least squares means for growth traits(BW8, BW20 and BW40), Egg production traits (EN40) and egg weight traits (EW32 and EW40) were computed in DD, KK, DK and KD genetic groups separately in each generation. In general, crosses performed better than pures (P<0.05) for EN40 over the generation, (DD Vs DK and KK Vs KD). The heritability estimates for DD and KK, pure lines for BWg were ranging from low to moderate across the generations. However, the heritability estimates for BWg for crosses ranged from medium to high across the generation. The estimates of h2 for BW20 and BW40 were moderate to high in magnitude in all the genetic groups across the generations. The estimates of heritability for EN40 pooled over generations for DD, DK, KK and KD genetic groups were 0.107 ± 0.054, 0.115 ± 0.049, 0.292 ± 0.073 and 0.131 ± 0.048 respectively. The estimates observed in KK line were higher in all the generations as compared to DD line except in third generation. The estimates in crosses were higher than the pures. Selection based on crossbreds performance can bring about genetic improvement in EN40 at fairly good rate. The heritability estimates for EW32 and EW40 in pure lines were low to high in magnitude. The genetic correlations amongst body weight traits (BW8, BW20 and BW40) were moderate to high in magnitude and in desired direction. All phenotypic correlations were statistically highly significant (P<0.01).
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AN ANALYSIS