22 BULLETIN 1104, U. S. DEPARTMEI^J'T 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 resume 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 



