Heri-tabillty of age at first egg(AFG),number of egg to 300 days old(NE-300d),egg weight(EW)and num-ber of egg to 500 days old(NE-500d) were 0. 28,0.19,0. 58,0. 24,respectively.

• 开产日龄、300日龄产蛋数、蛋重、500日龄产蛋数的遗传力分别为：0.；28，0