THE RECIPROCAL INFLUENCES OF STOCK AND CI ON 



563 



The trifoliate stock is generally conceded to secure early ripening in 

 oranges. Florida experience seems to indicate that oranges on rough lemon 

 stock cannot be held on the trees as long as when grafted on sour orange.^" 



The grape, however, supplies the best examples of stock influence on 

 fruit ripening. Wickson states that the Riparias Gloire and Grand Glabra 

 induce ripening one to two weeks ahead of Rupestris St. George. Hed- 

 rick found that many American grapes on Gloire and Clevener stocks 

 consistently ripen their fruit ahead of the same varieties on their own 

 roots. In the St. George there was less uniformity of effect; in fact this 

 stock seemed to retard the ripening of some varieties. This difference of 

 a few days is likely to assume considerable practical importance with 

 late varieties in regions where autumnal frosts come early or where 

 autumnal rains are frequent. 



Husmann^^ considers that the degree of congeniality between cion and 

 stock influences the time of ripening. From this point of view it may be 

 inferred that the same stock may have a retarding effect on one variety 

 and hasten the ripening of another. Much conflicting evidence, in other 

 fruits besides grapes, may be reconciled in this way. 



Table 2, including data taken more or less at random from Husmann's 

 figures, indicates that this possibility may be realized. Taking Lenoir as 

 the standard, grapes on St. George have ripened, in one case 4 days ahead, in 

 another case 9 days after, Lenoir. Dog Ridge has ripened fruit on its 

 cion varieties 2 days ahead and 13 days after the same varieties on Lenoir. 



Table 2. — Ripening Dates of Grape Varieties on Different Stocks 

 {After Husmanrfi^) 



Data introduced later to show differences in the composition of fruit 

 on several stocks may be anticipated here. Those differences that are 

 found can be considered to represent such as might occur in separate 

 specimens on the same tree or vine. Much of the available data is from 

 European sources, or, if from America, it concerns such plants as are 



