136 Breeding Plants and Animals. 



improvements and should be done with intelligence and 

 with great care. 



In case of wheat, oats and other close-fertilized 

 plants we form permanent varieties successfully from 

 a single mother plant. In corn the plants are accus- 

 tomed to free open or cross-pollination, and incestuous 

 bleeding is disastrous. In swine too close breeding is 

 unwise. The fewest blood lines, blood of individuals 

 used as foundation stocks, which may safely be blend- 

 ed and yet avoid too close inbreeding have not been de- 

 termined. It would ordinarily pay to err on the safe 

 side. It is quite probable that the blood of a dozen 

 foundation animals, especially if two or three of them 

 v/ere males, could safely be so managed that continu- 

 ally crossing their blood lines would avoid the ill ef- 

 fects of breeding too close relationship and would al- 

 low for a few blood lines to be discarded, as pedigrees 

 showed that after all only a few blood lines were really 

 dominating the entire new breed. This has been the 

 experience in breeding Thoroughbred horses and 

 doubtless would occur here. It may be that families 

 would be secured which would stand very incestuous 

 breeding, as there is variation in this as in all other 

 characteristics.* As _tlie elimination goes on from year 

 to -year the few choicest original foundation animals, 

 or those animals of exceptional breeding power which 

 may be produced in the course of this blending ( really 

 hybridizing) of the best obtainable Poland-China blood, 

 will rapidly become the whole of the county breed. If 

 the tests are kept up theories of close breeding and 

 line breeding may be developed and even proved. But 

 the tests for intrinsic quality- will do the guiding. 

 Branches of the new family which are inclined to go to 

 pieces because of inbreeding will fall out. The blood 

 of only those which stand the rigid tests will be per- 

 petuated. And those blood lines which are best suited 



*See N. H. Gentry's paper on "Inbreeding: Berkshires" in Vol 

 1, of the* Proceedings of the American Breeders' Association, W. 

 M. Hays, Secretary, Washington, D. C. 



