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THE DISAPPEARANCE OF WATER CORE AND THE OCCURRENCE OF INTERNAL 

 BREAKDOWN IN WATER-CORED RICHARED DELICIOUS DURING STORAGE 



William J. Lord 

 Department of Plant and Soil Sciences 



Delicious and its strains are susceptible to water core, a disorder 

 chiefly associated with mature and over mature fruit. Mild cases of 

 water core may disappear during storage, but severely affected fruit often 

 develop internal breakdown. Since it is not always possible for growers 

 to harvest their Delicious before they become severely affected with this, 

 disorder, it is essential to determine when internal breakdown appears 

 during storage and if its occurrence can be predicted with any reliability. 



Materials and Methods 



To determine the disappearance of water core and the occurrence of 

 internal breakdown in Red Delicious, fruit seriously affected with this 

 disorder were harvested on October 10 and 15, 1953. Fruit harvested on 

 each date were obtained from trees in separate blocks in the University 

 orchards at Amherst. 



The fruit were composited and one sample examined for the presence 

 of water core within several hours of harvest and another after remaining 

 at room temperature for 7 days. The percentage of water-cored fruit was 

 recorded and its severity classified as slight (less than 30 percent) , 

 medium (30 to 50 percent) , and severe (more than 50 percent of the cross - 

 sectional area of the fruit affected) . The remaining fruit were placed 

 in regular cold storage at 32 -3 6 F in air within several hours after 

 harvest. At approximately monthly intervals, two samples of fruit from 

 each harvest date were removed from storage to determine the presence 

 and severity of water core and internal breakdown. One sample was exam- 

 ined on the day of removal and the other after remaining at room temper- 

 ature for 7 or 8 days . 



Results 



The percentage of fruit affected with water core decreased except 

 during the last month of storage (Figure 1) . Most of the water core of 

 medium and severe classification disappeared from both lots of Delicious 

 by mid- January, however (Figure 2). On the other _hand, the data in 

 figure 3 show that approximately 12 percent of the apples harvested on 

 October 15, 1963, stored until November 12, and examined on November 19, 

 had internal breakdown. Although not shown, approximately 6 percent of 

 the Delicious harvested on October 10, 1963, stored until December 13, 

 and examined on December 20, had internal breakdown. 



The severity of internal breakdown increased during storage (Figure 1) 

 and increased during the 7 day holding period at room temperature after 

 each removal date (Figure 3) . 



