In an attempt to determine optimum time of 

 harvest for stored fruit, both varieties were harvested 

 over the period of late September through mid October 

 in 1 998, 1 999, 2000, and 200 1 . At each harvest, ten to 

 thirty representative fruit were selected from each 

 variety, and brought to the lab for measurement of size, 

 internal ethylene and starch hydrolysis to estimate 

 fruit maturity, and firmness as a crude indicator of 

 quality. Internal ethylene was measured by gas 

 chromatography, starch degradation was rated using 

 the Cornell Generic Starch Index, and firmness was 

 measured with either a Wagner pressure tester or an 

 EPTl pressure tester. A bushel or more of fruit was 

 harvested from each cultivar on 

 selected harvest dates and placed 

 in refrigerated air storage at 32°F. 

 Fruit from one harvest in 1998 

 were also stored in controlled 

 atmosphere storage (CA), at 38°F, 

 2.8%02, and varying CO^ up to 

 5%. 



Harvest data are presented in 

 Tables 1 and 2. Table 1 shows 

 extensive year-to-year differences 

 in harvest qualities of the fruit. 

 All factors listed in the table 

 varied significantly from year to 

 year. Harvest dates were not 

 exactly the same every year (as 

 shown in Table 2), but the same 



time span was evaluated. The fact that 

 the Shizuka were not as firm as the 

 Mutsu may be atfributed in part to 

 earlier ripening rather than being 

 inherently less firm. 



Table 2 illustrates the influence of 

 harvest date on firmness of Mutsu and 

 Shizuka. Starch Index is an indicator of 

 progression of ripening. As expected, 

 firmness decreased with later harvest 

 of both cultivars, and Starch Index 

 increased with later harvest. Year-to- 

 year differences in all three measure- 

 ments were found, but in all years 

 Mutsu was the firmer apple and had a 

 lower starch index on any given date. 

 Starch degradation appears to be a good 

 indicator of fruit ripening in both Mutsu and Shizuka. 

 Even taking into consideration that Shizuka could 

 probably have been harvested up to a week earlier than 

 Mutsu at comparable starch scores, Shizuka was never 

 as firm an apple as Mutsu. Internal ethylene 

 concentrations were quite variable and are not shown. 

 Since Mutsu and Shizuka are both green to yellow 

 fruit, color should be a minor factor in choosing time of 

 harvest, although both cultivars can develop an 

 attractive pink blush during the ripening period. Over 

 half of the fruit of both cultivars did develop this pink 

 blush covering at least 5% of the fruit's surface area. 

 Further, the conversion from green to yellow would be 



Table 3. Fiminess (Ibs)^ of Mutsu and Shizuka fruit on removal from 

 storage. 



Firmness was measured with a Wagner penetrometer in 1998 and with an 

 EPTl inl999, 2000, and 2001. 



Fruit Notes, Volume 67, Summer, 2002 



