M.7 EMLA 



M.7A 



M.26 EMLA 



Ott.3 



YZ& 1989 

 ■■ 1990 



9/22 



9/24 



9/26 



9/28 



9/30 



Figure 2. The relative date in 1989-90 of the beginning of ripening (date when the average 

 internal ethylene level reached 1 ppm) of apples from Summerland Red Mcintosh trees on 

 various rootstocks planted in 1985. 



tained with Delicious were confirmed with 

 Mcintosh, i.e. M.7A and M.7 EMLA appeared to 

 delay ripening, and Ott.3 appeared to advance 

 ripening. The magnitude of the differences, 

 however, was not large. These trees were only 

 in their fifth and sixth leaf, so at least two years 

 of additional data will be required to confirm 

 these responses. 



The results presented here, along with those 

 presented in the last issue of Fruit Notes 



[52(2):8-9] on the 1984 NC-140 Trial, give some 

 indication of the relative effects that rootstock 

 can have on apple ripening. Furthermore, it is 

 obvious from the data in Figures 1 and 2 that the 

 effects are not consistent in their magnitude. I 

 do not believe that rootstock can be used reliably 

 to expand the harvest season; however, it is 

 valuable for growers to realize that in some 

 years there can be very dramatic responses. 



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Fruit Notes, Summer, 1991 



