18 MASS. EXPERIMENT STATION BULLETIN 440 



Smith and Fellers (1934), Manville, McMinis and Chuinard (1936), Todhunter 

 (1939), and others have discussed the differences in vitamin A, B, and C content 

 in different varieties of apples. Some investigators have indicated that the vita- 

 min C content of apples tends to increase as the chromosome number in the cells 

 of vegetative tissues increases, but Smith and Fellers (1934) did not observe any 

 such correlation. 



Environment and Climate 



Besides genetic factors the composition of the apple may also be significantly 

 influenced by environmental factors. The effect of climatic conditions on the 

 composition of apples has been studied extensively by Shaw (1911) and Caldwell 

 (1928a, 1928b). According to Caldwell it would appear that the annual crop of 

 fruit upon a perennial plant is an integrated expression of the climatic factors for 

 the season in which it is produced in the same degree to which the growth of an 

 annual plant is integrated with these factors. He further indicated that the 

 mean summer temperature as a separate factor has little influence in determining 

 the composition of apples. 



Murneck (1945) compared the composition of apples during development to 

 harvesting maturity on the outside portion of the tree with better exposure to 

 light, and that of apples developed on shaded branches. The apples on branches 

 with better light were almost invariably higher in ascorbic acid content than 

 those grown on shaded branches. This was not merely "skin-deep," but extended 

 within the flesh of the fruit. The smaller apples were somewhat higher in ascorbic 

 acid than the larger ones. Moreover, if a limb carried a relatively light crop, 

 the vitamin content of the apple was apt to be somewhat higher than where the 

 yield was heavy. It was also reported that the ascorbic acid concentration in 

 fruit borne on weak trees, was higher than in fruit on trees of high vegetative 

 vigor. The ratio of the leaf area to fruit in relation to the vitamin C content of 

 Delicious and Winesap apples was studied by Batchelder and Overholser (1936). 

 The Winesap seemed to show^ higher vitamin C values when the ratio was low, 

 but the Delicious apples showed no differences. The leaf-fruit ratio seemed not 

 to affect the vitamin C content directly. 



Soil and Fertilizer Treatment 



Wilder (1909) of Massachusetts Experiment Station determined the soil 

 adaptations of various varieties of apple trees and indicated that different vari- 

 eties have decided preferences as to soil. However, Shaw (1911) states that 

 "not enough is known regarding this question to make any very definite generaliza- 

 tion on the subject." 



The effect of fertilizers was investigated by Aldrich (1931), who applied sodium 

 nitrate (Chili saltpeter) during the months of August and September and 

 then studied the quality of the apple fruit. This treatment decreased the 

 color, increased the nitrogen content and had no measurable effect on keeping 

 quality. 



Magness and Overley (1930) studied the keeping quality of apples from un- 

 treated and from nitrate- or potash-treated trees, but found no significant dif- 

 ferences. 



Todhunter (1937) reported results of studies of apples from unfertilized, nor- 

 mally fertilized, and heavily fertilized soil. No differences were found, either in 

 the vitamin C content or in the nitrogen content of the apples. In general the 

 beneficial effect of sunlight on color and flavor is well known. The quality and 



