LUTHER BURBANK 



or more recently developed varieties of spineless 

 opuntias appear to have lost altogether the capac- 

 ity to revert to the spiny condition. Even under 

 the most adverse conditions of soil and climate, 

 they remain absolutely smooth. One other step 

 of progress, and, we may confidently predict, the 

 factors for spininess will be so completely elim- 

 inated from the germ plasm, that the spineless 

 opuntias will breed true from the seeds. 



Even then, it must not be expected that the seed- 

 lings in any given case will reproduce all the good 

 qualities of the parents; any more than the seed- 

 lings of cultivated varieties of apple or pear or 

 peach will duplicate the qualities of their parents. 

 We have seen that the seedlings of the thornless 

 blackberry are not precisely like the parent form. 

 But they all are thornless. Such will be the case, 

 ultimately, with the spineless opuntias. 



And it must be obvious that when this condi- 

 tion is attained, the experiment of developing the 

 opuntias in any direction will be greatly facili- 

 tated. With many varieties of spineless opuntias 

 in hand, each one absolutely free from the ten- 

 dency to revert to the spiny condition, we shall be 

 able to carry forward experiments in crossbreed- 

 ing and selection through which any desired 

 quality may be accentuated and developed. 



At the present time, for example, the spineless 



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