6 



BULLETIN 1406, U. S. DEPARTMENT OE AGRICULTURE 



varieties at the various stations where observations were made are 

 shown graphically in Figures 1 to 9. The size of the apples, given 

 in cubic centimeters, is based on calculations from circumference 

 measurements, assuming the fruit to be a sphere. The volume of 

 the fruit is slightly less than this, but the data for each variety 

 are comparable and give a more accurate indication of the actual 

 increase in size than would be obtained by circumference measure- 

 ments. For purposes of comparison, a 2-inch apple on this basis 

 would have a volume of about 65 cubic centimeters, a 2% -inch apple 

 125 cubic centimeters, and a 3-inch apple about 220 cubic centimeters. 

 These data are based on measurements of the same apples taken from 

 rime to time in the different sections and are representative of the 

 actual increase in size occurring at the different dates. The data 

 are averages of 50 to 100 apples. 



From the data shown in Figures 1 to 9 it is apparent that the 

 increase in size of the fruit continues as long as the apples remain 



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Pig. 1. — Change in firmness of flesh and size of Jonathan apples, 1923 



attached to the tree. Many of the measurements on which these 

 data are based were made after the commercial picking season had 

 passed and when the crop as a whole was dropping very badly; 

 yet it is apparent that growth in size continued at a very nearly 

 uniform rate. For example, in 1923 the Baldwin apples at Amherst 

 were dropping considerably by October 6, yet measurements made 

 October 8 showed growth to be continuing in those apples which 

 still adhered to the tree. At Rosslyn so many Baldwin apples 

 had dropped by September 17 that it was impossible to get further 

 measurements, yet up to that date growth was continuing at a 

 practically uniform rate. The data for 1924 show a similar con- 

 dition. Delicious apples at Wooster, Ohio, were showing a medium 

 drop and were apparently ready to pick on October 12, yet growth 

 continued at a uniform rate throughout the remainder of the 

 month. Jonathan at Wenatchee appeared ready to pick on Sep- 

 tember 10, but showed a marked increase in size between that date and 



