storage of Marshall Mcintosh: 

 Some Cautions for 1989 



Wesley R. Autio, William J. Bramlage, and William J. Lord 

 Department of Plant & Soil Sciences, University of Massachusetts 



Marshall Mcintosh is presently the most widely 

 planted strain of Mcintosh in the Northeast. In a 

 previous issue of FruzYATofes [52(4): 1-5] we reported on 

 tree, fniit, and storage characteristics of Marshall in 

 comparison with 6 other strains. Marshall trees were 

 similar in size to Morspur, Imperial, Macspur, Gatzke, 

 and Rogers trees and yielded similar amounts. 

 Marshall fruit colored earlier and to a higher degree 

 than other strains, and Marshall fruit ripened 3 to 5 

 days earlier than the other strains. Marshall trees 

 produced relatively small fruit, but in most years they 

 were not significantly smaller than Rogers fruit. 



We also evaluated the storage potential of Marshall 

 and found no consistent differences between it and 

 other strains with regard to softening or the develop- 

 ment of storage disorders in refrigerated (32°F) or 

 controlled atmosphere (CA) (37°F, 3% O2, 5% COg) 



storage. However, when commercial CA's were 

 opened in 1988 a number of growers reported off- 

 flavors and other injuries only with Marshall, which 

 suggested that Marshall may be more sensitive to low 

 O2 levels than other strains. To test these observations, 

 we harvested 2 bushels of fruit from each of 8 Rogers 

 and 8 Marshall trees (planted in 1979 in a replicated 

 trial) . One bushel from each tree was kept in 3% O2 and 

 5% COj, and the other bushel was kept at 2.25% O^ and 

 5% COj. After 6 months of CA, 1 month of refrigerated 

 storage, and 6 days at room temperature, the incidence 

 of I0W-O2 injury was assessed. 



L0W-O2 injury can manifest itself in a number of 

 ways including presence of off-flavors, purpling of the 

 skin, and development of brown sunken patches on the 

 surface. The most common symptom noted in this 

 study was internal browning as shown in Figure 1. The 



Emit Notes, Spring, 1989 



