others, but this was true 

 across time and treatment 

 and was not treatment-re- 

 lated). Untreated fruit accu- 

 mulated very high ethylene 

 concentrations, and 1-MCP 

 only delayed the rise, the 

 fruit eventually reaching 

 about the same level as the 

 untreated ones. Untreated 

 ones softened excessively, 

 although it should be noted 

 that they were stored beyond 

 the normal limits for Mcin- 

 tosh. 1-MCP-treated fruit 

 also softened, but much less, 

 and were still acceptably 

 firm after the longer storage 

 time. The untreated fruit also 

 scalded during the longer 

 storage time, whereas 1- 

 MCP treatment prevented this from happening. 



The Retain"" treated fruit harvested three weeks 

 later responded much the same as the three strains, 

 except that ethylene increased far less and no scald 

 developed. These differences are not likely associated 

 with 1 -MCP, but rather occurred because Retain™ has 

 the effect of reducing ethylene, and late harvest 

 reduces scald. 



Delicious. Redchief Delicious were harvested on 

 October 1 and October 1 1 , treated with 1 -MCP, and 

 stored in 32F air for 90 or 1 50 days, and then for 7 more 

 days at 70F. Subsamples were weighed at harvest, 

 placed in paper bags, and stored like the others, and 

 reweighed at removal from storage and again after 7 

 days at room temperature. 



Fruit from the two harvests responded the same to 

 treatment and storage, so in Table 4 the means of the 

 two harvests are presented. Ethylene content of 

 untreated fruit increased substantially with storage 

 time and after transfer to 70F. 1 -MCP again caused 

 ethylene content during storage to fall below that at 

 harvest, but it rose over time and during fruit warming, 

 although it never approached the ethylene levels of 

 untreated fruit. Untreated fruit softened greatly during 

 storage and at room temperature. 1-MCP treated fruit 

 also softened, but not nearly as much as the untreated 

 fruit. Both treated and untreated Delicious lost weight 

 during and following storage, but 1-MCP reduced the 



size of this loss. 



Spigold. In order to determine if 1-MCP could 

 inhibit ethylene production even if fruit were already 

 producing substantial ethylene, Spigold were har- 

 vested October 22 (very late!) with average Starch 

 Index of 7.6 (Cornell generic chart) and average 

 internal ethylene concentration of 3 1 ppm. Fruit were 

 treated like the other cultivars, and stored for 90 or 1 50 

 days in 32F air, plus 7 days at 70F. Table 5 shows that 

 the ability of 1-MCP to reduce ethylene production 

 was significant despite the fact that the fruit were 

 already producing a substantial amount of ethylene 

 prior to the 1-MCP treatment. 1-MCP treated fruit 

 were firmer, too, although there was substantial fruit- 

 to-fruit variation in firmness due to very large fruit 

 sizes. 



Discussion 



Treatment with 1-MCP consistently resulted in 

 firmer fruit following cold storage. This firmness 

 advantage remained or was enhanced after fruit were 

 left at room temperature for a week. 1-MCP-treated 

 fruit did, however, soften over time, just not as much as 

 did the untreated fruit. Ethylene production was 

 suppressed well into the storage period. The duration 

 of this suppression was cultivar dependent. Ethylene 

 production was essentially shut down by 1-MCP 



Fruit Notes, Volume 67, Summer, 2002 



