LUTHER BURBANK 



until man undertook the education of the fruit 

 and trained it for that particular purpose. 

 REMOTE SUGAR-PRODUCING ANCESTORS 



Nevertheless all that we know of heredity 

 suggests that the effort on the part of man to 

 develop such a trait as this would not have been 

 successful had it not chanced that there were 

 among the ancestors of the prune some races that 

 possessed a tendency toward the peculiar prop- 

 erty of producing very sweet fruit. There is noth- 

 ing anomalous in that supposition, however, for it 

 is well known that many tropical fruits tend to 

 have a high sugar content. 



Such is the case, for example, with the date, 

 the fig, and the pineapple. 



The orange, also, in some of its varieties, is a 

 very sweet fruit, and there are numerous others 

 among the fruits still confined to the tropics that 

 show the same quality. 



Indeed, in general it may be said that fruits 

 growing in the tropics tend to have a high sugar 

 content, the reason being, perhaps, that in hot 

 climates this is necessary to insure preservation 

 of the fruit long enough to permit it to serve its 

 purpose in protecting the seed during its growth 

 and preparation for germination. 



But as fruits migrate to temperate zones, they 

 tend to give up this habit of sugar production. All 



[86] 



