190 FUNDAMENTALS OF FRUIT PRODUCTION 



season (see Fig. 24) ; terminal fruit buds on long shoots obviously must be 

 differentiated at a later period than is known to characterize formation 

 on spurs. Considerable variation in the time of differentiation occurs 

 also in young spurs which have never before formed fruit buds. Even in 

 bearing spurs, when they form fruit buds, the formation may occur from 

 early July to late August. Spurs which had blossomed during the current 

 season but failed to set fruit varied still more; some of the earliest 

 differentiation observed was found in spurs of this class and later differ- 

 ention also occurred. 



Magness^^T [^ q^ careful study of axial buds found resting stages of 

 leaf buds in several varieties as early as July 9 and early in September 

 he recognized differentiation into flower buds. Some of his preparations 

 taken in December suggest an initial differentiation into fruit buds, 

 though he evidently did not regard them as such. In the Tetofski apple 

 he considered some differentiation to have occurred about the first of 

 August. He states that a spur bud of July 23 showed as much develop- 

 i^ent as the most advanced axillary buds of Sept. 2. In the investi- 

 gations of the following year the "main period of axillary fruit-bud 

 formation in the varieties studied began after August 1, and a great 

 many buds were apparently being differentiated on September 8. This 

 was fully one month later than spur buds on the same trees." 



Direct comparisons of the time of differentiation in buds of stone 

 fruits in different positions are not available. Roberts, ^^^ however, 

 finds in September a difference in the development of buds on sour 

 cherries according to their positions on the 4- or 5-inch shoot. This 

 difference suggests that flower formation is initiated first both in the basal 

 and in terminal regions. It is probable that a similar condition occurs 

 in the peach. 



Goff'''^ found little or no difference in the comparative develop- 

 ment of flower buds in rooted runners and parent plants in the 

 strawberry. 



Varietal Differences. — Bradford"-^ found considerable difference be- 

 tween varieties of apple in the stage of development attained early in 

 August, indicating a lack of uniformity in the time of differentiation. 

 Of the varieties observed, Stark, Red Astrachan and Oldenburg seemed 

 farther advanced than Jonathan, Northern Spy and Grimes. The 

 season of ripening of the fruit appears to make little difference in the 

 time of differentiation; there appears to be, however, some correspond- 

 ence, though not absolute, between the order of blossoming and the order 

 of differentiation. Magness^^T found White Pearmain, Tetofski and 

 Yellow Transparent noticeably advanced in development in early July 

 as compared with Lady and Jonathan. 



Goff''^ found considerable difference between varieties in the time 

 of fruit-bud formation, some forming fruit buds before Aug. 1 while some 



