LUTHER BURBANK 



cions of this second generation that we now graft 

 into membership in the aristocratic cherry colony. 



And when, after another interval of two years, 

 these cions come into flower and are mutually 

 cross-pollenized, the seeds they bear, being the off- 

 spring of mixed dominants (Bb xBb), will pro- 

 duce a generation of seedlings precisely repeating, 

 as regards the quality under consideration, the 

 formula of their parent generation. In a given 

 lot of four thousand, let us say, one thousand will 

 be BB, two thousand will be Bb, and one thousand 

 will be b b. 



And precisely the same difficulty in selection 

 confronts the experimenter that confronted him 

 before. 



If he could only know which are the pure domi- 

 nants and which the mixed one, all would be well. 



But not only is it impossible for him to know 

 this, but he may not be able even to determine 

 with certainty, from examination of the foliage of 

 the seedlings, which ones belong to the group of 

 three thousand that bear the dominant factor 

 (either BB or Bb), and which to the group of one 

 thousand that bear only recessive factors (bb). 



It must be borne in mind that the experimenter 

 is really considering a large number of qualities, 

 and it must be understood also that there may 

 not be any clearly established point of correlation 



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