LUTHER BURBANK 



selection is made with an eye to the production of 

 a commercially valuable variety of flower or fruit 

 or vegetable, and not merely for the purpose of 

 scientific record. 



We have seen this illustrated again and 

 again; and we have seen also how great are the 

 complications which result when we are called 

 upon to make a selection that will give us not 

 merely one quality — merely size or a given color 

 or sugar content — but a combination of six or 

 eight or ten qualities, all presented in superlative 

 measure. 



We have seen that the chance of securing any 

 given combination of qualities decreases at a 

 startling geometrical ratio in proportion as the 

 number of qualities increase. 



The precise formula, as calculated by the 

 biometricians, runs something like this. In case 

 a single pair of qualities is in question — say high 

 protein content versus low protein content in 

 corn — the chances are, if the two strains are 

 crossed, that there will appear in the second 

 generation of their progeny one offspring in four 

 that closely resembles each parent. 



But when we are considering two qualities — 

 say protein content and height of ear on the 

 stalk — in combination, the chance that there will 

 be an individual of the offspring like each parent 



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