140 POULTRY PRODUCTION 



As will be readily seen, the male offspring (XX) receives a 

 double dose (BB) of the barring factor, while the fenaale 

 offspring (XO) receives only a single dose {B) which comes 

 from her sire. 



Male 

 Parents (xB) (xB 



Offspring XB XB XB O 



The inheritance of high fecundity resembles the inheritance 

 of barring in one important particular. It is never carried 

 by a female-producing ovum. On the other hand, it may or 

 may not be carried by the male-producing ova, or by the 

 spermatozoa. Suppose, for the sake of illustration, the 

 very unusual case of a male that is pure for high production 

 and that he is mated with a female that is a high producer. 

 If Li represents high production, the mating may be repre- 

 sented as follows: 



Parents 



Offspring XL, XL, XL« O 



As may readily be seen, the daughter would be a high 

 producer, because she carried Li. The highly interesting and 

 significant fact is that she received this Li from her sire and 

 not from her dam. The son, on the other hand, received the 

 Li factor from both sire and dam. 



Unfortunately, males that are pm-e for Li, as. indicated 

 above, are very rare, and those carrying even a single dose 

 of Li are not common. The fascinating problem of making 

 them more frequent through line breeding confronts the 

 constructive breeder. For the sake of clearness, and to come 

 closer to what may occur in actual breeding practice, assume 

 the case of mating a male that does not carry the Ln factor 



