LUTHER BURBANK 



might better be referred to as a "unit complex," 

 or by some allied term that would suggest its com- 

 plicated character. The word "gene-complex" has 

 been suggested in a similar connection. 



It would appear that the real purpose of se- 

 lective breeding through many generations is to 

 remove one after another of the factors that dom- 

 inate or mask other factors, so that subordinate 

 or recessive factors may make themselves man- 

 ifest. 



No one who has experimented widely will 

 doubt that it is possible by a series of selections 

 extending over several generations to accentuate a 

 given character, say to bring out the crinkled for- 

 mation of the poppy petal, or the corrugations in 

 the leaf of a wild geranium, or an added row of 

 petals in a balloon-flower. And it goes without say- 

 ing, that, according to the modern terminology, the 

 character thus isolated must be represented by an 

 hereditary factor which was present in each suc- 

 cessive generation utilized in our experiment, but 

 which for some reason was not enabled to make 

 its influence so potentially felt in earlier genera- 

 tions as it was in later ones. 



And the only logical explanation appears to be 

 that in each successive generation of the plants 

 carefully selected and inbred, there was a new re- 

 distribution of factors, always along Mendelian 



[228] 



