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

Table 9 Predicted egg production related traits 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 (%)
AFE	157.69	180.70	165.80	167.02	− 2.0**	− 1.3*	− 0.7
OP	24.31	26.21	25.11	25.29	− 0.6	0.1	− 0.7
EN43	129.03	92.06	113.29	112.14	2.5*	1.4	1.0
NC43	11.76	23.62	18.16	18.67	2.7	5.6	− 2.9
ACL43	14.16	3.95	6.79	6.45	− 25.0**	− 28.8**	3.8
APL43	1.30	1.26	1.24	1.22	− 3.1	− 4.9	1.7
EN72	280.65	201.23	253.34	247.39	5.1**	2.7*	2.5
NC72	33.18	70.86	53.06	51.31	2.0	− 1.4	3.4
ACL72	9.72	2.89	4.98	4.90	− 21.1**	− 22.2**	1.1
APL72	1.59	1.88	1.47	1.52	− 15.3*	− 12.6	− 2.7
EN100	379.91	270.33	362.67	352.77	11.6**	8.5**	3.0
NC100	59.83	110.21	94.83	90.23	11.5**	6.1*	5.4
ACL100	6.75	2.50	3.97	3.93	− 14.2**	− 15.1**	0.9
APL100	2.57	2.41	1.88	1.93	− 24.6**	− 22.3**	− 2.3

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, AFE age at first egg, OP oviposition period, ENX cumulative egg number till X weeks of age, NCX number of clutches till X weeks of age, ACLX average clutch length till X weeks of age, APLX average pause length till X weeks of age

ISSN: 1297-9686