New York Agricultural Experiment Station. 517 



or any mechanical change hut rather that it is due to some physi- 

 ological disturbance. It may be due to a difference in the specific 

 gravity in the sap of stock and cion. It may be that the food 

 elaborated by the foliage of the cion is different from that which 

 the stock would have had with its own foliage. Possibly it is in- 

 sufficient nutrition of stock or cion. These are but conjectures as 

 to how the vigor and productiveness are influenced. Another set 

 of theories might be made as to causes of the varying adaptability 

 of the grafted vines to soil and still another, as to why some root- 

 stocks are inimical to phylloxera and fidia. They are thus briefly 

 brought up to suggest further experimental work and to urge them, 

 as physiological disturbances, as more probable causes than me- 

 chanical injuries. 



Selection of stocks for grafting grapes. — It is necessary in seek- 

 ing for a vine to be used as a rootstock to obtain a well-established 

 variety which can be depended upon to behave in a uniform man- 

 ner. Wild vines of any species would be quite too variable for 

 practical purposes. Wild vines, too, as a rule are too slender of 

 growth to bear the stockier cultivated grapes which when grafted 

 on them overgrow the rootstock. The French, who have been pio- 

 neers in this work, have selected a number of strong-growing varie- 

 ties of several American species and our growers are fortunate 

 enough to have this very considerable help if they desire to try 

 grafting. The behavior of the stocks in tliis experiment leads us 

 to recommend all three for trial in commercial vineyards, though 

 since Clevener is exceedingly hard to find it may be necessary to 

 start with St. George and Gloire both of which may be purchased 

 at reasonable rates from California nurserymen. To these might 

 well be added Kiparia grand glabre and the two hybrids between 

 Vitis riparia and Vitis rupestris known as 3306 and 3309. 



Procedure in growing a grafted vineyard. — Should it be demon- 

 strated that grapes of certain varieties can be more profitably 

 groAvn on other roots than on their own and that grafting grapes is 

 profitable, nurserymen or growers must raise stocks for grafting 

 as well as varieties for cions. It is not within the province of this 



