THE RECIPROCAL INFLUENCES OF STOCK AND CION 565 



one-half the difference between the two blooming periods." It seems 

 quite possible that this difference can exist in one climate and not in 

 another. A retarded entrance into the rest period in the autmnn is 

 shown elsewhere to delay the opening of peach blossoms in the spring. If 

 the plum stock prolongs growth in the fall, it will evidently have a re- 

 tarding effect on blossoming in the spring. However, the rest period is a 

 retarding factor only in climates with mild winters and early springs and 

 it is only in such climates that the retarding influence of plum stocks would 

 become obvious. In the north the rest period ends before the dormant 

 period and no retarding influence from the stock would be expected. 



Baco^ recorded considerably more copious bleeding in Baroque and 

 Tannat grapes grafted on various American and hybrid stocks than on 

 their own roots. He also reported differences in the time of breaking of 

 the buds ; those on the own-rooted vines opened much more regularly and 

 somewhat earlier than those on the grafted vines. As a rule the vines 

 on hybrid stocks blossomed later and more irregularly. ■■* 



Here again, as in the ripening of fruits, it is in Europe and particularly 

 with grapes that more attention is given to slight differences due to stocks 

 and here again climatic factors explain the few differences observed. 



Several European commentators are inchned to emphasize the need 

 of substantially the same seasons of growth inception in stock and cion 

 to insure compatibihty. Lindemuth states that his investigations have 

 led him to the same conclusion in this respect as that of Lucas, to wit : a 

 graft of an early starting kind on a late starting kind is never successful: 

 " . . . late starting kinds grafted on early starting stocks, very fre- 

 quently become sick, since they are not able to take up the quantity of 

 sap which the early-starting seedling offers. Canker injuries at the point 

 of grafting are very often the consequences of defective grafts of this 

 kind. Less easily does the early starting cion become sick on late starting 

 sorts. The more nearly equal in time and strength the growth of the 

 cion and stock are, the better, according to the opinion of Dr. Lucas, is 

 the success of the graft." ^''- 



An expression of the same influence in the apple in Brittany is fur- 

 nished by Duplessix;^^ "... if one inserts a cion of Doux Normandie 

 [blossoming in June] on a stock from seed of Launette [blossoming late 

 in April], the sap will ascend in the trunk 6 weeks before the graft is 

 ready to receive it. The tree may die. If it lives the sap will accumulate 

 in the swelling at the base of the graft and this swelling . . . can 

 become in its turn a cause of death. ... If the reverse be tried, the 

 cion of Launette will require sap when the Doux Normandie trunk is 

 not ready to provide it and the cion of Launette will perish or it will grow 

 slowly for want of feeding at a useful time. 



"... A stock starting earlier than the graft is preferable to one 

 starting later." 



