LUTHER BURBANK 



duce thorny bushes exclusively, owing to the dom- 

 inance of the factor for thorns. But if a few ber- 

 ries or individual drupelets of a berry had been 

 fertilized with pollen from a flower of the thorn- 

 less plant itself, these would (according to a for- 

 mula with which we are already familiar) stand 

 one chance in four of combining recessive fac- 

 tors and thus of producing thornless progeny. 



And of course from there onward the case pre- 

 sented no difficulty. The plant experimenter was 

 now at hand to make sure that the thornless flow- 

 ers were fertilized solely with pollen of their own 

 sort. This of course could bring together only 

 recessive factors, that is to say, factors for thorn- 

 lessness, and the result could not be in doubt. 

 The thorn-producing factor would be left entirely 

 out of the composition of bushes sprung from 

 such a union, and they would inevitably be thorn- 

 less. 



THORNLESS, BUT LACKING QUALITY 



But while the production of a thornless race 

 of dewberries was thus accomplished with com- 

 parative ease, once the material with which to 

 work had been supplied, it must be understood 

 that this was really only the beginning of the task. 



The original berries from which the thornless 

 vines were grown were of no commercial value. 

 They were small and of very indifferent flavor. 



[14] 



