SYSTEMS OF BREEDING 



6l 



variability, and rapidly reduces it to a minimum. Moreover, 

 whatever variations do occur will be in line with the prominent 

 diameters of the chosen 

 branch of tJie breed. 



Advantages of line 

 breeding. The nature of 

 results secured by this 

 system can almost cer- 

 tainly be predicted ; and 

 when they do appear, and 

 improvement is at hand, 

 it is backed up by the 

 most powerful hereditary 



influence obtainable, be- FIG. 50. Baron Duke 63d, a line-bred Berkshire. 



Property of A. J. Lovejoy, Rosco, Illinois. 

 Figures 51 and 52 show get of this boar 



cause of the simplicity 

 and strength of the an- 

 cestry, which, if the selection has been good, all " pulls " in the 

 same direction. The records of all breeds will show the pro- 

 nounced results that have followed judicious line breeding. A 

 volume could be filled with pictures of famous animals so pro- 



FIG. 51. Line-bred Berkshire pigs. Get of Baron Duke 63d 



duced. Those shown are of swine, for the reason that the pig is 

 popularly supposed to be the most sensitive to close breeding. 



Disadvantages of line breeding. The chief danger in line 

 breeding is that the breeder will select by pedigree, abandoning 



