22 BULLETIN 1104, U. S. DEPARTMENT OF AGRICULTURE. 
area. Within a single tree the variation in size of individual fruits 
produced is undoubtedly due in general to variation in the nutritive 
supply to the different fruits. Heavily loaded or shaded branches 
will produce small fruit, while branches with good foliage and bear- 
ing very few apples will usually produce large specimens in com- 
parison with the rest of the tree. 
RESUME OF FACTORS CONDUCIVE TO INTERNAL BROWNING. 
There are a number of factors which undoubtedly contribute to 
bring about conditions in the fruit conducive to internal browning 
when that fruit is placed in storage. Unfortunately, most of these 
factors, other than storage temperature, are beyond the control of 
the fruit grower or handler. A résumé of conditions found to be 
associated with the tendency of Yellow Newtown apples to brown 
internally in storage is helpful, however, in giving the conditions 
toward which the orchardist should strive in order to reduce or elimi- 
nate this trouble. It is, perhaps, of greater importance that these 
data give a basis for a fairly accurate prediction of the probable per- 
centage of browning that will develop in any crop. If conditions 
are right for the development of browning in the fruit, special pre- 
caution should be taken to prevent the storage of that fruit at low 
temperatures. 
Internal browning has been most prone to occur in fruit from the 
lower portions of the Pajaro Valley, where conditions of low tem- 
perature and high humidity during the growing season are coupled 
with very fertile soil. The sunshine and the temperature and air 
humidity during the growing season are obviously beyond the con- 
trol of the orchardist. While internal browning is not unknown 
in other apple-growing regions, it occurs to such a small extent that 
it is not of commercial importance. This indicates that apples from 
the Pajaro Valley differ from those from other sections in the ten- 
dency to brown internally in storage only in degree, and it is ap- 
parently the peculiar growing conditions in this valley which often 
produce rather large fruits of coarse texture that are responsible 
for the widespread tendency to browning. 
Even in the Pajaro Valley, however, there are certain seasons in 
which very little browning develops in the fruit, and in seasons 
when browning does develop there are certain trees the fruit from 
which develops very little browning as compared to that from other 
trees about them. And even from trees most of the fruit of which 
shows bad browning certain apples will remain entirely sound in 
cold storage. 
All these facts indicate that internal browning is due to some 
condition within the tree, probably nutritional, which affects the 
fruit. This condition may be very general, and a large percentage of 
