is^EW YoKK Agkioultukal Expekiment Station. 511 



11.2; Clevener, 11.9. From these figures may be roughly calcu- 

 lated the number of tous per acre as follows : own roots, 2.24 ; St. 

 George, 3.02 ; Gloire, 3.3S ; Clevener, 3.59. 



The question at once arises : Is the greater productiveness due 

 to an influence of the stock on the cion or to the effects of grafting 

 acting as annular incisions, the '^ ringing " of the grape-grower, 

 are known to act ? This question will be taken up later. 



In Table III, the yields for 1911 are given. The crop of this 

 year was the only one borne uniformly over both experimental 

 plats, fate this year having granted immunity from the troubles 

 of other seasons. The figures of 1911, therefore, admit of some- 

 what closer analysis than those in Table II. Making the same 

 calculations for the three stocks, the figures stand as follows : 

 pounds per vine on own roots, 14.51; St. George, 17.72; Gloire, 

 17.59; Clevener, 18.00; tons per acre on oa^ti roots, 4.39; St. 

 George, 5.36; Gloire, 5.32; Clevener, 5.62. 



Table III. — Average Yield Per Vine of Own-root and Grafted Grape 



Varieties, 1911. 



