EVERY FARMER A PLANT BREEDER 93 



test and scales have been doing right along for the 

 dairy cow. It indicates the individuals that are 

 worth perpetuating. 



LAWS OF PLANT IMPROVEMENT 



The two fundamental principles behind plant im- 

 provement are heredity and variation. Upon these 

 two you must build your structure; but you must 

 finish it and beautify it by selection. Heredity is 

 the law that like produces like. Variation is the 

 law that works to produce new things. Heredity 

 is the law of uniformity. Variation is the law of 

 change. Heredity is satisfied with what now ex- 

 ists. Variation goes out to explore — to seek new 

 paths and new fields. The plant breeder builds 

 upon the present heredity, but he courts variation 

 and urges it to seek new findings. If these are to 

 his liking, he seizes them as his own, attaches them 

 to the old heredity and builds the new structure 

 higher and better. The work is now to fix the new 

 acquisition and to make it a part of the building 

 material. Variation all the while is allowed free 

 range that it may gather in new discoveries for 

 further improvement and use. We let heredity 

 hold, keep and guard the values of the best fitted 

 animals, but we call in variation to improve them. 



But where is selection? If its role is so im- 

 portant, why is it not to be seen on this stage of 

 improvement? It is, if nothing in the play has 

 been struck out. Selection is man's part of the 

 drama. It is his work to decide which of the new 

 things that variation has found shall be held, which 

 new ones shall be cast aside, and at what point the 

 new acquisition is to be fixed as a part of the old 



