GENERAL POINTS CONCERNING FRUIT TREE STOCKS 179 



juicier fruits of a variety can be grown on some stocks than on 

 others, making them more palatable. Sweetness and sourness de- 

 pend on amount of sugar and acid; these, in turn, are influenced 

 by health, vigor, time of maturity and nutrition, all of which are 

 influenced by stock. A variety may, 

 therefore, be sweeter or sourer on one 

 stock than on another. There is noth- 

 ing to show that flavor is changed. 



10. Some stocks shorten the life of 

 the trees of which they are a part. 

 Apples on pears and pears on apples 

 are short-lived trees. Bartlett is short- 

 lived when top-worked on Kieffer. As 



FIG. 151-GRAFT PLANTING a rule '. grafting weak-growing species 

 on vigorous stock shortens the tree 

 life. 



226. Influence of grape stocks on cions. Much more is known 

 about influence of stock on cion in grape-growing than on tree 

 fruits. To epitomize : Experimenters of established reputation 

 hold that very appreciable differences may be noted between the 

 chemical and the physical composition of grapes, grafted on various 

 stocks and fruit of the same variety on its own roots. Among the 

 effects claimed the following are quoted: Fruit of grafted vines 

 is larger, has bigger seeds, thinner skin, berries are less numerous, 

 juice is more copious, is usually both more acid and sugary, is 

 less rich in phosphate, more highly charged with nitrogenous mat- 

 ters, has little tannin, less color and the color is less stable; vines 

 are more fruitful ; fruit ma- 

 tures earlier. These differ- 

 ences vary in different cases. 



In an experiment with grape 

 stock for American grapes 

 carried on for eleven years 

 at the New York station ma- 

 terial differences were found 

 between grafted and un- 

 grafted vines, all included in 

 the above summary. 



227. Influence of cion on 

 stock Cion in its turn has 

 a decided influence on stock. 

 For example, the form of 

 roots is much changed by the 

 cion. Thus, in starting ap- 

 ples in a nursery we bud 

 on seedlings which unbudded 

 would ha\e root systems 

 much the same, but at dig- 

 ging time the roots of the The knife cuts the roots at 12 to 

 various varieties are as below the surface. 



FIG. 152 NURSERY TREE DIGGER 



nches 



