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100 



130 160 190 



CALCIUM, OUTER CORTEX TISSUE(ppm) 



2 50 



Figure 1. Relationship between occurrence of internal breakdown in 

 Mcintosh apples after CA storage and the concentration of 

 calcium in the samples at harvest. Points represent 172 

 samples taken over a 4-year period. 



********** 

 POMOLOGICAL PARAGRAPH 



V/illiam J. Lord 

 Department of Plant and Soil Sciences 



Differences between M7 and M7a . Occasionally we are asked what is 

 the differences between Mailing (M) 7 rootstock and M7a rootstock. 

 The rootstocks are similar except that M7a has been selected for its 

 freedom from the so-called "latent viruses". These are viruses that 

 are commonly present in apple varieties and include stem pitting, 

 chlorotic leaf spot, platycarpa scaly bark and apple stem grooving. 



