44 Experiment Station Bulletin 345 



Apples harvested from half of trees receiving nitrogen and half of trees 

 receiving no nitrogen for the last three seasons were held in storage and 

 compared for the development of brown core. Also, apples from the 

 north side were compared with apples from the south side of the same 

 tree. When these data and similar records taken over a period of five 

 years were compared, there were indications that in some years apples 

 from trees low in nitrogen were less subject to the occurrence of brown 

 core than apples from high-nitrogen trees. Also, apples from the south 

 side of the tree were less susceptible to brown core than apples from the 

 north side of the tree. However, these differences were very small com- 

 pared to the seasonal differences, and in years when the appearance of 

 brown core was severe the differences due to treatments were negligible 

 in comparison with the total amount of brown core occurring. 



The prevalence of brown core in relation to weather conditions was 

 studied. There seemed to be an association between wet growing sea- 

 sons, or low temperatures during ripening, and the occurrence of brown 

 core. Internal browning, a disease similar to brown core occurring in 

 Yellow Newton apples, was found to be associated with low-temperature 

 growing conditions in the Pajaro Valley of California, and our records 

 show that in wet growing seasons, or seasons when the temperature has 

 been low during the ripening of the apple, brown core has been most 

 prevalent in our stored fruit. 



One of our cold-storage rooms was made gas-tight by using paint 

 prepared by the DuPont Company, with a bicycle inner tube gasket 

 around the door and grafting wax for sealing up the cracks. Four hun- 

 dred bushels of apples were placed in this room, and the concentration of 

 carbon dioxide was kept between 1 1 and 1 2 per cent and the temperature 

 at 40° F. This experiment demonstrated that a cold storage may be made 

 tight in this way without too much expense. Apples kept in this modified 

 atmosphere were free from brown core and until the last of March were 

 more crisp and harder than apples stored at 32°F. However, the lots 

 removed in April developed scald quickly and had a flavor that was 

 apparently caused by too high concentrations of carbon dioxide. This 

 injur\' may have been due to a drop in the temperature to 36°F. for a 

 few days in April, when the concentration of carbon dioxide was about 

 12 per cent. 



Some study has been initiated this year on the use of ice as a cooling 

 material for apple storage. Several storages already using ice for cooling 

 were investigated and critically analyzed. On the basis of these studies 

 an ice bunker was designed and a model built. The object of this ice 

 bunker is to melt the ice quickly to release more cold into the room than 

 would come about by ordinary melting. The ice bunker was designed in 

 a unit size so that as many units as were necessary could be placed in the 

 same storage, each unit working independently. It seems that at this time 

 with emphasis on conservation of energy and of food the use of natural 

 resources such as ice is a worthy war-effort project, and indications are 

 that it is good economy. (W. W. Smith) 



