Genetic parameters, reciprocal cross differences, and age-related heterosis of egg-laying performance in chickens

Table 8 Predicted egg weight for the four genetic groups and estimates of heterosis for the two reciprocal crosses

Trait	Genetic group				H% (WY)	H% (YW)	Reciprocal cross differences (%)
Trait	WW	YY	WY	YW	H% (WY)	H% (YW)	Reciprocal cross differences (%)
FEWt	44.97	40.55	43.20	44.95	1.0	5.1**	− 4.1
EWt28	55.63	45.52	51.53	52.85	1.9**	4.5**	− 2.6
EWt32	57.01	48.06	53.84	54.61	2.5**	4.0**	− 1.5
EWt36	58.25	49.33	54.96	56.15	2.2**	4.4**	− 2.2
EWt40	59.34	50.52	56.39	57.42	2.7**	4.5**	− 1.9
EWt44	59.80	51.47	56.98	58.26	2.4**	4.7**	− 2.3
EWt48	60.74	52.87	58.35	59.75	2.7**	5.2**	− 2.5
EWt52	60.39	53.21	58.37	60.04	2.8**	5.7**	− 2.9
EWt56	60.81	54.58	59.30	61.26	2.8**	6.2**	− 3.4
EWt60	62.41	55.90	60.90	62.55	3.0**	5.7**	− 2.8
EWt64	62.23	56.26	61.18	62.81	3.3**	6.0**	− 2.8
EWt68	62.01	56.34	61.42	62.98	3.8**	6.4**	− 2.6
EWt72	61.24	55.92	60.95	62.52	4.0**	6.7**	− 2.7
EWt76	62.17	56.73	62.33	63.41	4.8**	6.7**	− 1.8
EWt86	60.87	56.93	62.25	63.17	5.7**	7.2**	− 1.6
EWt100	61.85	57.82	62.80	65.20	4.9**	9.0**	− 4.0

H% (WY): percent heterosis for WY, the percentage of performance of WY being better than the average performance of the two parental lines, H% (YW): percent heterosis for YW, the percentage of performance of YW being better than the average performance of the two parental lines
Wald F statistics after adjusting with multiple testing for H% (WY), H% (YW), and reciprocal cross differences are indicated as follows *FDR ≤ 0.05, **FDR ≤ 0.01
YY Beijing-You chickens, WW White Leghorn chickens, WY offspring of a cross between White Leghorn as the sire line and Beijing-You as the dam line, YW offspring of a cross between Beijing-You as the sire line and White Leghorn as the dam line, FEWt weight for the first three eggs, EWtX egg weight at X weeks of age

ISSN: 1297-9686