STOCKS AND RESISTANT VINES 71 



tons. The crops on the grafted vines were increased through 

 the setting of more bunches and the development of larger 

 bunches and berries. 



The grapes on the vines grafted on Gloire and Clevener 

 ripened a few days earlier than those on their own roots, while 

 with St. George a few varieties were retarded in ripening. 

 Changing the time of maturity may be very important in grape 

 regions where there is danger of early frost to late-ripening 

 sorts, and where it is often desirable to retard the harvest time 

 of early grapes. 



In the behavior of the vines, the results correspond closely 

 with those given for yields. In the growth ratings of varieties 

 on different stocks, the varieties on their own roots were rated 

 in vigor at 40; on St. George, at 63.2; on Gloire, at 65.2; on 

 Clevener, at 67.9. There is no way of deciding how much 

 the thrift of the vines depends on adaptability to soil, and how 

 much on other factors. Since all of the varieties were more 

 productive and vigorous on grafted vines than on their own roots 

 it may be said that a high degree of congeniality exists between 

 the stocks and varieties under test. 



The experiment suggests that it would be profitable to grow 

 fancy grapes of American species on grafted vines, and that 

 it is well within the bounds of possibility that main-crop grapes 

 can be grafted profitably. In the general tuning-up of agri- 

 culture now in progress, it may be expected that soon Ameri- 

 can as well as European varieties of grapes will be grown under 

 some conditions and for some purposes on roots other than 

 their own. 



DIRECT PRODUCERS 



Attempts innumerable have been and are still being made to 

 secure, by hybridizing V. vinifera and American species of 

 grapes, varieties that will resist phylloxera, the mildew and 

 black-rot. The grapes of this continent are relatively immune 



