QUANTITY PRODUCTION 277 



large numbers of seedlings that we can hope to 

 find one or two that will show the desired com- 

 bination of traits in high degree. 



And the lesson which should be preeminently 

 inculcated is this : You must make many experi- 

 ments at plant breeding before j^ou can hope to 

 secure the final combination — the sequence of 

 qualities — that you desire. 



The Logic of Quantity Production 



Now note the application: Each individual 

 seedling of a hybrid strain represents a unique 

 combination of ancestral traits, and constitutes in 

 itself a new and unique experiment — equivalent 

 to an independent deal of the cards. So the prob- 

 afbilit}'^ of securing what we seek will be somewhat 

 proportionate to the number of seedlings. 



This is particularly true in the case of such 

 variable plants as the fruit trees of our orchards. 

 The case is far simpler when we are dealing with 

 plants that vary little in their qualities, or where 

 we are breeding with only a single pair or two 

 pairs of unit qualities in mind — say "hardness" 

 of kernel and immunity to rust, as in Professor 

 BifHn's experiments with wheat; or good flavor 

 and whiteness as in the white blackberry. 



But where the varied traits sought to be com- 

 bined in a Shasta daisy are in question; or the 



