132 LUTHER BURBANK 



bore small fruit. If, then, we assume that here, 

 as in many other cases of plant breeding, the 

 quality of largeness is dominant to the quality of 

 smallness, it may be expected that all the hybrids 

 of the first generation will tend to bear large 

 fruit. 



If, introducing our convenient system of sym- 

 bols, we designate the dominant quality of big- 

 ness with the letter B, and the recessive quality 

 of smallness with b y we may designate the mem- 

 bers of the hybrid generation as all being mixed 

 dominants, each bearing the factors Bb. This 

 means that the factor B dominates the factor b, 

 and that the individuals in question will all bear 

 large fruit. 



So we may expect (on this assumption), hav- 

 ing grafted our selected seedlings, that each of 

 them will show, two or three years hence, fruit 

 of large size, but unfortunately a thousand pre- 

 vious matings will always vitiate this desirable 

 result. 



But of course the other qualities of this fruit 

 will not be all that we could desire, so it will be 

 necessary to continue the experiment. 



Suppose we do this by cross-pollenizing differ- 

 ent members of the same group. We shall thus 

 mate Bb with Bb. And the result of this mating, 

 as we know, will be to produce, in each group of 



