Journal of Agricultural Research 
V<A, XXIV, No. s 
i68 
town exhibits a varietal characteristic of susceptibility to internal 
browning. 
The effect of the region in which the fruit is grown upon its suscepti¬ 
bility to browning is indicated by the fact that several varieties of apples 
such as the Yellow Bellflower and the Red Pearmain, which normally 
show no tendency to brown, are susceptible to this disease when grown 
in the Pajaro Valley. These varieties do not brown when grown in any 
of the other Yellow Newtown districts. Furthermore, the Yellow New¬ 
town, when grown in this valley is much more susceptible to internal 
browning than when grown elsewhere. The climatic conditions of the 
Pajaro Valley, therefore, seem to exert an influence upon the develop¬ 
ment of apples which has not been shown to occur elsewhere and which 
rtoders them susceptible to this disease. 
R^I^TION OF TIME OF HARVESTING TO INTERNAL BROWNING 
The importance of the time of harvesting of the fruit in the control of 
nonparasitic diseases of the apples has been stressed by Powell and 
Fulton (ij). Brooks, Cooley, and Fisher (4, 5, 6), and others. Corre¬ 
spondence with cold-storage managers showed that some of them believe 
that internal browning is, at least in part, the result of picking the apples 
too green. The riper apples which have a higher sugar content, according 
to these men, are more resistant to browning. 
An investigation of the effect of the time of harvesting upon internal 
browning was started in the season of 1919-20. Three pickings of 
fruit were made for both this and the 1920-21 seasons. The fruit of the 
first picking was “hard green'' in maturity and of a solid green color; 
that of the second picking was “ firm green" and signs of the yellow color 
were becoming evident; while the fruit of the last picking was “ overripe" 
for harvesting and showed a considerable amount of yellow over the 
entire siuiace. The fruits for each lot were picked from all portions 
of the same trees at each of the pickings and were then stored under 
identical conditions at o® and 2.2° C. The effect of the time of harvest¬ 
ing upon the severity and rate of browning are shown in Tables I and II. 
The figures of Table I indicate that the later-picked fruit browned 
much more severely in every test. In the case of the apples stored at 
2.2® C. during the season 1919-20, the actual figures in the table show 
little difference in the amount of browning. When the difference in the 
storage dates is taken into account, however, a considerable difference 
in favor of the earlier pickings becomes apparent. In the other cases the 
relation of time of harvest to the browning is obvious. 
The figures of Table II indicate that the fruit of the last picking browned 
two and one-half times as rapidly as that of the second picking and the 
fruit of the second picking browned one and one-half times as rapidly 
as that picked at the beginning of the harvest season. 
The sugar content of the fruit picked at the time of harvest September 
26, October 16, and November 6 was 9.4, 10, and ir.4 per cent, respec¬ 
tively, which appears to indicate that a higher sugar content favors 
browning. By analyzing a large number of samples, however, it was 
shown that the sugar content does not influence the resistance or sus¬ 
ceptibility of the fruit to browning. It might also be expected that the 
change in acidity of the fruit of the later picking, due to its more mature 
condition, and the subsequent prolonged storage would affect its resistance 
to browning. This was found not to be true. Although the titrable 
