THE PROPAGATION OF APPLE TREES. 95 



Transparent, which uniformly gave as large a callus as any variety, did 

 not root as well as Wagener, which never gave any sign of callus forma- 

 tion. 



Neither can we discover any relationship between rooting from the 

 scion and season of maturity, either of fruit or wood, nor in size of leaves 

 or density of foliage. 



Many woody plants are propagated from cuttings, and in general it 

 is those with soft wood that grow most readily. There is considerable 

 variation in hardness of wood among different varieties of apples, and 

 we may inquire if those with softer wood are the ones that root most 

 readily from the scion. No extended investigation of this question has 

 been made at this station. Beach and Allen ^ made extensive tests of 

 the hardness of wood of different varieties. They found considerable 

 difference withm the variety, and a clear comparison of their results with 

 rooting ability, as shown by their investigation, is difficult, but a general 

 survey of their results leads to a belief that there is a general correlation. 

 It is, however, subject to exceptions. Beach and AUen came to the con- 

 clusion that there was a correlation between hardness of wood and resist- 

 ance to winter cold, and here again there seems to be a rather loose cor- 

 relation with rooting ability. Oldenburg and Wealthy are very hardy 

 and root poorly, and Bough is tender and roots well. But Ben Davis is 

 quite hardy and roots comparatively well, and Hubbardston and Tolman 

 are less hardy than Wealthy and do not root so well. 



Wide variations in the rooting ability of different lots of the same 

 variety are evident. Some of these are clearly seasonal. Such differences 

 may be due to climatic conditions, to soil conditions, — for the soils used 

 in different years are not all alike, — or they may be due to difference 

 in the scions used. Any such difference would most likely trace back to 

 the gi'owing conditions the previous season as affecting stored food and 

 possibly structure. Slight differences in cultural treatment may have 

 had an effect. Varying rainfall may have had an influence. It is im- 

 possible from the evidence at hand to determine which of these possible 

 factors have had an influence and to what extent. 



The general low percentages of Series 6 (Table 5) are striking, and the 

 writer feels that they are due largely to poorly drained soil which prevailed 

 over a considerable portion of the plot. While no direct comparisons are 

 possible, careful observation indicated that rooting was better on the 

 drier portions of the plot. A part of the plot on which Series 4 was grown 

 was poorly drained, and may account for the rather low average of this 

 series. 



1 la. Expt. Station Res. Bui. 21 (1915). 



