2 BULLETIN 1406, U. S. DEPARTMENT OF AGRICULTURE 



solve. If too immature when picked apples will wilt in storage and 

 be poorly colored and unattractive in appearance; they will be of 

 poor quality and lacking in aroma and flavor when they reach prime 

 eating condition; and many varieties will be very likely to develop 

 bad storage scald. On the other hand, it is very important that cer- 

 tain varieties be picked before becoming overripe. Internal break- 

 down — the softening and discoloration of the flesh of such varieties 

 as Jonathan and, more rarely, Grimes Golden, St ay man Winesap, 

 Delicious, Esopus Spitzenburg, and others — appears to be asso- 

 ciated with allowing the fruit to remain too long on the trees. The 

 development of water-core also appears to be associated with over- 

 maturity on the tree. 



Various tests are used by growers to determine the proper time of 

 picking apples. The color of the seeds, the ground color or color of 

 the unblushed portion of the fruit, the extent and intensity of the 

 blushed surface, the ease of separation of the fruit from the tree, and 

 the apparent firmness of the flesh are used to determine the time when 

 the fruit is in proper condition to be removed from the tree. Ex- 

 tended critical studies have not heretofore been made to determine 

 the exact dependability of these various tests, particularly for fruit 

 growing under the various climatic conditions prevailing in different 

 parts of the country or in the same section from year to year. Con- 

 sequently, a series of investigations was inaugurated by the United 

 States Department of Agriculture in cooperation with several State 

 agricultural experiment stations to study carefully the changes which 

 take place in apples as they approach maturity on the tree. 



The most prominent of these changes are (1) increase in size, (2) 

 change in color of seeds, (3) change in the color of the unblushed 

 portion of the fruit, (4) development of blush or red color on colored 

 varieties, (5) progressive softening of the fruit, and (6) change in 

 the tenacity with which the fruit adheres to the tree. 



It was proposed to study all these changes in order to determine 

 if possible (1) which of them constitute the most reliable criteria 

 for judging when the fruit is ready to be picked, (2) how these 

 ripening changes differ in the same variety when grown in different 

 sections of the country under widely varying climatic conditions, 

 (3) the effect of a long or short growing season on the time of ripen- 

 ing of the variety, and (4) whether an early bloom necessarily indi- 

 cates early ripening and a late bloom late ripening. 



EXPERIMENTAL METHODS 



In order to obtain standard observations on the fruit, an attempt 

 was made to eliminate so far as possible the variations in observa- 

 tions due to the personal factor. The general outline of the observa- 

 tions and tests was carried on simultaneously in the experimental 

 orchards at Amherst, Mass.; Ithaca, N. Y.; East Lansing, Mich.; 

 Wooster, Ohio ; Council Bluffs, Iowa ; Eosslyn, Va. ; and in commer- 

 cial orchards at Wenatchee, Wash. 



Observations and tests were made at 10-day intervals, starting 

 several weeks prior to picking dates in the different sections, as 

 follows : 



