BURBANK IN THE ORCHARD 



plex hybrid the diverse traits of different species. 

 Of course only two species can be blended 

 in a single cross, so repeated crossings will be 

 necessary. 



Obviously, then, it is desirable to shorten as 

 much as possible the interval between generations. 

 And Mr. Burbank has learned that the way in 

 which this may best be accomplished is by cutting 

 the seedling from its own roots, and grafting it as 

 a scion on the branch of a mature tree. 



He has discovered that if the graft is placed 

 on the trunk of a tree or on a large branch, it will 

 develop less rapidly than if placed on a twig near 

 the end of a branch. So he grafts his seedlings 

 in this way when they are very small, putting 

 them on branches that are usually not more than 

 half an inch in diameter. Thus placed, the scions 

 usually bear fruit in the second year (exception- 

 ally, even in the first), whereas if they had been 

 left to grow on their own roots they might not 

 have borne until the fifth or sixth year. 



Thus an experiment may be carried through 

 four or five generations in the time that would 

 otherwise be required for two generations. By 

 the adoption of such time-saving methods, Mr. 

 Burbank has been able to crowd the work of sev- 

 eral human generations into a single lifetime. 



There are several methods of grafting, but the 

 essential principle with all of them is merely that 

 the inner or living layer of the bark called the 

 cambium layer of the stock and scion shall be 

 brought in contact, not necessarily throughout its 



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