Selection 



381 



production of daughters from hens that had a good first-j^ear 

 record, it was frequently observed that the daughters were less 

 productive, although in some tests the higher the first-year rec- 

 ord of a hen, the better the egg production of her daughters. 



The use of pedigrees has been practiced as the basis for selec- 

 tion in some animals. It is a very ancient method; perhaps the 

 oldest pedigree records are the ancient records kept by the Arabs 



TABLE 23 

 Distribution of Alfalfa Plants for Pod Setting, in Per Cent 



(Modified from Fryer.) 



for horses. A pedigree is nothing more than a list of the parents, 

 grandparents, and other ancestors of a plant or animal so far as 

 is known. Pedigree breeding is merely breeding by mating to- 

 gether two individuals whose pedigrees are known. Pedigrees 

 have been used as a criterion for selection in the breeding of 

 poultry. This method has produced some good results but has 

 certain limitations. Jull considers that the pedigree method 

 can be combined advantageously with the method of perform- 

 ance, suggesting that if two hens have the same first-year record 

 for egg production, the one with the better pedigree is to be 

 preferred. However, he warns that there is no guarantee that a 

 hen of good ancestry will always produce good progeny. Jull 

 suggests further that variation in environmental conditions over 

 a period of years detracts greatly from the reliance that can be 

 placed upon pedigrees and that normally very little significance 



