Scientific Aspects of Luther Bur bank' s Work 



three generations he has now carried his Hne by 

 steadily selecting, and the percentage of no-stone 

 fruits is slowly increasing, while quality, beauty 

 and productiveness are also increasing at the same 

 time. 



The plum-cot is the result of crossing the 

 Japanese plum and the apricot. The plum-cot, 

 however, has not yet become a fixed variety and 

 may never be, as it tends to revert to the plum and 

 apricot about equally, although with also a ten- 

 dency to remain fixed, which tendency may be 

 made permanent. 



Most of Burbank's plums and prunes are the 

 result of multiple crossings in which the Japanese 

 plums have played an important part. Hundreds 

 of thousands of seedlings have been grown and 

 carefully worked over in the twenty years of ex- 

 perimenting with plums, and single trees have 

 been made to carry as many as 600 varying seedling 

 grafts. The Bartlett plum, cross of the bitter 

 Chinese Simoni and the Delaware, itself a Simoni 

 hybrid, has the exact fragrance and flavor of the 



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