were seen among the strains, suggesting that there were no differences with 

 respects to the time of ripening. However, the starch-iodine test is not very 

 sensitive for assessing small differences. 



Table 2. Starch index values of fruit from different strains of Mcintosh 

 harvested in 198J, 1984, 1985, and 1986. 



1983 198M 1985 1986 



Strain 9-9 9-17 9-4 9-11 9-18 9-3 9-10 9-4 



* Within columns, means not followed by the same letter are significantly 

 different. 



During the course of apple ripening the internal C2H4 concentration rises 

 dramatically, providing an accurate and sensitive means of monitoring ripening. 

 For three harvests in 1984 and 1985 the internal C2H4 concentration was 

 determined for Marshall and Rogers fruit (Table 3). We were particularly 

 interested in determining if Marshall fruit ripened earlier, since they colored 

 significantly earlier than the other strains. Rogers was selected as a 

 standard strain. In both years, Marshall fruit ripened significantly earlier 

 than Rogers fruit, showing higher internal C2H4 concentrations at each harvest. 

 In 1986 internal C2H4 concentrations were determined for all strains on 

 September 4 (Table 3). Marshall fruit had the highest levels, and over the 

 three years of the study comparison of concentrations suggest that Marshall 

 fruit ripen about 5 days before standard strains such as Rogers. 



The primary factor in determining success when growing Mcintosh is red 

 color. For an orchard to be profitable, a large percent of the fruit produced 

 must have enough red color to meet the U.S. Extra Fancy grade, i.e. 50 percent 

 red color characteristic of the cultivar. Table 4 shows the percent of the 

 fruit meeting the Extra Fancy grade for each harvest in each year. In all 

 cases Marshall had the highest percent of fruit in the Extra Fancy grade. 

 Also, earlier coloring of Marshall fruit can be observed in those years where 

 multiple harvests were made. 



Flesh firmness was measured at harvest each year (Table 5). Significant 

 differences were noted among the seven strains. However, these differences may 

 be attributed to differences in fruit size (Table 6). Generally, the smallest 

 fruit were the firmest. 



