Effects of Selection For Four Week Body Weight on Some Parameters in Japanese Quail (Coturnix coturnix japonica) 1. Genetic Parameters


Abstract: This research was carried out to determine the genetic effects of divergent selection under two different selection pressures for 4. week body weight over 3 generations on 4 week body weight and related characters such as slaughter weight, carcass weight, breast weight and leg weight in Japanese quail. Individual selection for body weight was carried out at 4 weeks, separately for each sex. The proportion kept was 10% for males and 30% for females in H1 and H2 lines, and 20% for males and %60 for females in H3 and H4 lines. H1 and H3 lines were selected for high body weight, H2 and H4 lines were selected for low body weight, H5 was a control line. Weighted selection differentials obtained for 4 weeks body weight of 3 rd generation of Line 1, Line 2, Line 3, Line 4 males were 30.70 g, -139.67 g, 31.35 g, -107.45 g, respectively. Similar weighted selection differentials for females were 2.46 g, -62.62 g, 25.25 g, -56.46 g, respectively. At the end of three generations, total genetic improvement obtained for 4 weeks body weight in Line1, Line 2, Line 3 and Line 4 were 23.28 g, -8.52 g, 20.22 g, 14.12 g for males and 25.06 g, -12.83 g, 19.88 g, 14.79 g for females, respectively. Realized heritabilities were 0.75, 0.06, 0.64 for Line 1, Line 2, Line 3 males respectively, 0.59, 0.20, 0.75 for females, respectively. Heritability estimates from half sib analyses were 0.60±0.66, 1.00±0.50 for Line 1 and Line 3 males, 0.68±0.40, 0.61±0.37 and 0.86±0.29 for Line 1, Line 2 and Line 3 females respectively. Heritabilities from regression of offsprings on sires were 0.69±0.55, 0.80±0.40, 0.15±0.39 for Line 1, Line 3, Line 4 males, 0.70±0.32, 0.10±0.20, 0.80±0.40 and 0.12±0.20 for Line 1, Line 2, Line 3 and Line 4 females, respectively. Phenotypic and genetic correlations between 4 weeks body weight and slaughter weight. Carcass weight, breast weight, thigh weight were found to be positive and moderate levels in females than in males. It was concluded that genetic improvement under high selection pressure for four week body weight will be more effective in both directions.

Keywords: Japanase Quail (Coturnix coturnix japonica), Body Weight. Divergent Selection, Genetic Parameters.

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