ids, watercore, and starch analysis. 



The dates of the beginning of ripening are 

 presented in Figure 1 . The effects of crop on fruit 

 ripening were eliminated in the statistical 

 analysis, since roots tock can alter crop load 

 substantially, and crop load has a dramatic 

 effect on fruit ripening. Means in Figure 1 have 

 been adjusted appropriately. There was a great 

 deal of variation in the date of ripening from 

 year to year; however, a few relationships were 

 consistent. Generally, fruit from trees on M.27 

 EMLA and Ott.3 ripened earlier than average, 

 and fruit from trees on M.7 EMLA and OAR 1 

 ripened later than average. The difference be- 

 tween the earliest and the latest ripening 

 ranged from only a few days in 1989 to 17 days 



in 1988. Firmness, soluble solids, watercore, 

 and starch data are not presented but they were 

 consistent with the results presented in Figure 

 1, which are based solely on ethylene produc- 

 tion. 



The second trial utilized Summerland Red 

 Mcintosh on M.7A, M.7 EMLA, Ott.3, and M.26 

 EMLA planted in 1985 at the Horticultural 

 Research Center. Samples were taken for ripen- 

 ing studies in 1989 and 1990. Sample size and 

 sampling procedure for internal ethylene analy- 

 sis were similar to those described above. 



Figure 2 depicts the date of the beginning of 

 ripening of fruit from trees on these four 

 roots tocks. As in the first trial, the effects of crop 

 load were removed. Generally, the results ob- 



M.7 EMLA 



OAR 1 



MAC 9 



M.9 



Ott.3 



M.27 EMLA 



V///////////A 

 sWWWN 



V///////A 



1988 

 VZ& 1987 

 ■H 1988 

 ^ 1989 



Y///////A 



'////////A 



9/20 9/25 9/30 10/5 10/10 10/15 10/20 



Figure 1. The relative date in 1986-89 of the beginning of ripening (date when the average 

 internal ethylene level reached 1 ppm) of apples from Starkspur Supreme Delicious trees 

 on various rootstocks planted in 1980 and 1981. 



Fruit Notes, Summer, 1991 



