LUTHER BURBANK 



This wide diversity of form and vigor in the 

 first generation hybrids is a rather unusual phe- 

 nomenon. As a rule, we have observed that first 

 generation hybrids are somewhat uniform in char- 

 acter, and that the tendency to wide diversity ap- 

 pears in the second generation. Indeed, attention 

 has more than once been called to the fact that 

 the discovery that such is the tendency among 

 hybrids was the one that put me on the track of 

 most of my successful plant developments. 



At the time when my experiments in hybridiz- 

 ing the Japanese plum and the almond were com- 

 menced, there were few, if any, other plant experi- 

 menters anywhere in the world who seemed fully 

 to grasp the principle that variation occurs in the 

 second generation, and that it is by raising large 

 numbers of second generation hybrids from which 

 to make selection, that the development of new 

 and useful varieties of plants may best and most 

 rapidly be carried out. 



This principle is so familiar to-day that horti- 

 culturists and botanists who refer to it very com- 

 monly overlook the fact that the recognition of 

 the principle is very recent. 



Twenty-five years ago I found it impossible to 

 convince most well known horticulturists and bot- 

 anists and biologists with many of whom I had 

 some spirited discussions on the subject that the 



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