LUTHER BURBANK 



condition had shown prepotency, and ajl the seed- 

 lings that grew from thornless berries thus cross- 

 fertilized were at once seen to be bearers of 

 thorns. 



This was precisely the experience that had dis- 

 heartened me, when, back in 1880, I had made the 

 experiments with the Wachusetts partially thorn- 

 less blackberry, to which reference was made 

 above. But in the intervening time I had made 

 many thousands of hybridizing experiments, and 

 I now clearly understood what at the earlier 

 period I had known vaguely if at all that in such 

 a case as this we must look to the second filial 

 generation for the kind of results we are seeking. 



The case is precisely comparable to that of 

 the white blackberry, for example, or to that of 

 the stoneless plum. When the white blackberry 

 is crossed with a black blackberry all the off- 

 spring of the first generation are black. And when 

 the stoneless plum is crossed with the stone-bear- 

 ing plum all the offspring of the first generation 

 are stone-bearers. But in each of these cases the 

 succeeding generation will show individuals in 

 which the submerged character reappears we 

 shall have white blackberries and stoneless plums 

 agkin. 



So I had every reason to believe that a com- 

 parable result would be achieved if the thorny 



[18] 



