THE MONTHLY BULLETIN. 



CALIFORNIA STATE COMMISSION OF HORTICULTURE. 

 Vol. III. November, 1914. No. 11. 



STOCKS FOR FRUIT TREES. 



NEW \ 

 By U. P. Hedrick,* Agricultural Experiment Station, Geneva, N. T. QAkOK 



Nearly all fruit trees are consorts of two individuals. We distinguish 

 the parts of the consorting tree as stock and scion — terms which need 

 no definition. Fruit growers refuse to believe that the stock has any 

 influence on the scion — at least the industry of growing fruit is carried 

 on with little or no regard to the interactions of stock and scion. Yet 

 there is no doubt but that stock and scion do react the one upon the 

 other and that all fruits propagated by budding and grafting are influ- 

 enced for better or worse by the stocks upon which they are worked. 

 Experiments, experience and observation show that the physiological 

 functions at least of both root and top are modified the one by the 

 other. To this fact most of those who have given study to the question 

 now agree, though they are not in accord as to the degree of the influ- 

 ence and the explanations offered by all are more or less hypothetical. 



It is not a matter of wonder that fruit growers do not believe that 

 the stock affects the scion, for we know little about it and "nothing is 

 so firmly believed as that which a man knoweth least." Nowhere can 

 one find clear cut definitions and careful analyses of the effects of the 

 stock upon the scion. Everywhere, there is much misconception and 

 not a little deception in the use of stocks in the propagation of fruit 

 trees, so that fruit growers do not know what the best stock for a par- 

 ticular fruit is, or, if they do know, they can not be sure that their 

 trees are on the stocks of their choice. To complicate the situation fur- 

 ther, results in the use of all stocks are profoundly modified by coil 

 and climatic conditions, causing man to draw widely varying conclusions 

 and more than all else, bringing about the state of '"confusion M^orse 

 confounded" that we now have in the whole matter of stocks for fruits. 



Were one to discuss the mutual influence of stock and scion in detail, 

 citing examples of the manifold phases the subject assumes, he could 

 easily fill a volume, a large one, and as interesting as large. In the time 

 at my disposal, however, and for the topic under consideration, ' ' Stocks 

 for Fruits," I can but briefly touch upon such parts of the subject as 

 show the influence of the stock on the scion. Avoiding details and all 

 taint of theory, let us consider the w^ays in which the stock influences 

 the scion. 



First — The stock modifies the form and stature of a plant. Pears 

 on quince, apples on Douein or Paradise roots, and cherries on the 

 Mahaleb are familiar examples of the dwarfing effects of stocks. In- 

 creased size less often, if ever, occurs. The altered size and forms of 



♦Address before the State Fruit Growers' Convention, Davis, California, June 1 

 to 6, 1914. 



1—13557 



