PROPAGATION AND FRUIT-STOCKS 349 



the proportion rooting from the cion; fertile, well-drained, 

 sandy loam, soils offer the best conditions for securing a high 

 percentage of rooting trees; there seems to be a relation 

 between the varietal ability to produce roots from the cion 

 and the thickness of the cambium layer during the dormant 

 season. 



313. Relation of cion and stock. — Little has been added 

 to the literature on this subject during recent years other 

 than that already mentioned. It has commonly been con- 

 sidered that each part, i. e., stock and cion, maintained its 

 own individuality with such exceptions as when dwarf trees 

 were produced by working on slow-growing stock. It was 

 argued that the trees and fruit in an orchard of Baldwin 

 apples, for example, were always practically the same, allow- 

 ing a reasonable amount of natural or continuous variation, 

 and such other differences as could easily be traced to environ- 

 ment factors. Additional exceptions were noted occasionally, 

 such as the effect of a given variety on the root system as 

 could be seen clearly when the trees were dug from the 

 nursery; and a tendency of an individual tree to be more 

 prolific, earlier or later in bearing than was usual for the 

 variety. 



The question may now be raised as to whether the relation 

 of stock and cion is not more important than previously sup- 

 posed, and whether the whole problem of congenial stocks 

 for fruit varieties may not need investigation. 



PROPAGATION OF FRUIT-TREES 



In the foregoing paragraphs it is apparent that most of 

 the tree-fruits are grown on a foreign root system, i. e., the 

 root parts are of seedling origin, largely for the reason that 

 fruit-trees do not "come true " from seed. It is not the prov- 

 ince of this text to deal in detail with the practice or manipu- 

 lation of the processes used in general plant propagation, 



