30 



Percent of Total 



without Breakdown 

 With Breakdown 



to 1 



2 to 3 3 to 4 5 to 6 



Seeds per Fruit 



7 to 8 



Figure 1. Seed numbers for Mcintosh apples that did or did not develop senescent 

 breakdown after 6 months of storage in 32''F air plus 1 week at room temperature. 

 "Percent of total" is for each population — those that developed breakdown, and 

 those that did not develop the disorder. 



In this experiment we did not determine the occur- 

 rence of disorders after storage of fruit, because there 

 were not enough fruit for a meaningful test. However, 

 in another experiment we had the opportunity to relate 

 seed number to keeping quality. 



Bushel samples of Mcintosh apples had been col- 

 lected from 50 different blocks in commercial orchards, 

 and all had been stored at 32°F in air at the Horticul- 

 tural Research Center for 6 months. They were then 

 kept at room temperature for 1 week, and each fruit 

 was cut open, its seed number counted, and it was 

 recorded as to whether or not senescent breakdown 

 had developed. 



The results are shown in Figure 1. We examined 

 the results as two populations of fruit — those that had 

 breakdown and those that did not have it. In the 

 population that developed breakdown, a high propor- 



tion of the fruit had 3 seeds or less. In the population 

 that did not develop breakdown, most of the fruit had 

 5 or more seeds. A statistical analysis showed that a 

 real difference in seed number did exist between the 

 two populations. Thus, in these Mcintosh from com- 

 mercial orchards throughout Massachusetts, low seed 

 number appeared to be a contributing factor (though 

 certainly not the only factor) in development of senes- 

 cent breakdown, a disorder caused by calcium defi- 

 ciency. 



These results demonstrate that low seed number 

 probably contributes to low calcium concentrations in 

 Mcintosh and Delicious apples, and also contributes to 

 calcium-related disorders during and following stor- 

 age. This means that one approach to maintaining 

 adequate calcium levels in apples is to pay careful 

 attention to pollination conditions in orchards. Seeds 

 are important contributors to fruit quality. 



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12 



Fruit Notes, Summer, 1989 



