THE RECIPROCAL INFLUENCES OF STOCK AND CION 



573 



on Black Hamburg. Pepin '^'^ stated that certain almonds grafted on 

 bitter almond or on St. Jiilien plum stocks bore smaller fruit. His 

 statement of a stock which produced small fruit in the apple has been 

 mentioned earlier. Daniel^^ found that tomato grafts on pimento pro- 

 duced less fruit than on their own roots and that the fruit was generally 

 smaller. The Golden Pippin in England when worked on free growing 

 stock was said to l)c larger, mealy and poorer in keeping quality than 

 on less vigorous stock. "^^ In America some of the older generation of 

 pear growers thought that small fruited varieties, such as Dana's Hovey, 

 bore larger fruits when worked on vigorously growing stocks. The sand 

 cherry has been said to produce larger fruits on Prunus americana than 

 on its own roots."^ IVIany California growers believe that peach roots 

 induce larger fruit in both European and Japanese plums than plum or 

 almond roots. ^^^ Hedrick,''^ however, reported no difference in numerous 

 varieties of apples grown on Doucin, Paradise and standard stocks. 



Reference has been made to the greater growth of American grapes 

 on certain stocks in an experimental planting in New York.''^ The same 

 investigation showed much greater productivity in the grafted vines. 

 Typical comparisons are shown in Table 5, condensed from Hedrick's 

 results. Summarizing, on an acre-yield basis, the results for all varieties, 

 including many not listed in the table just given, the yields by stocks for 

 that year were, in tons per acre: on own roots, 4.39; on St. George, 

 5.36; on Gloire, 5.32 and on Clevener, 5.62. Averages for 3 years were in 

 the same order of magnitude. 



Table 5. — Average Yield per Vine of Own Root and Grafted Grape Varieties, 



1911 



(After Hedrick-'^) 



Variety 



Ovvn roots, 

 pounds 



St. George, 

 pounds 



Gloire, 

 pounds 



Clevener, 

 pounds 



Campbell . 

 Concord. . 

 Vergennes 

 Herbert. . 



lona 



Niagara . . 

 Catawba . . 

 Delaware . 

 Brighton . , 

 Worden . . 



16.00 

 16.20 

 17.36 

 12.21 

 15.17 

 20.51 

 15.37 

 12.75 

 14.43 

 10.37 



23.69 

 16.93 

 22.13 

 11.89 

 16.42 

 22.55 

 12.95 

 24.25 

 15.56 

 16.47 



20.41 

 16.95 

 24.52 

 14.95 

 17.68 

 24.57 

 16.41 

 14.25 

 13.06 

 15.95 



18.35 

 21.17 



21.79 

 21.94 

 17.75 

 17.40 

 15.71 



"The crop on the grafted vines was increased," Hedrick states, 

 "through the setting of more bunches and the growth of larger bunches 

 and berries. The increase in the number of bunches was easily deter- 



