532 



FUNDAMENTALS OF FRUIT PRODUCTION 



Muller-Thurgau" found a similar correlation between fruit size 

 and number of seeds in grapes, as is shown in Table 7, and Valleau^^^ 

 found the size of strawberry fruits closely correlated with the number 

 of their akenes. 



Table 7. — Relation of Seed Number to Fruit Size in Grapes 



{After Mailer- Th urgau « ^) 



It should not be inferred, however, that seedless fruits are always 

 smaller than seed-containing fruits of the same varieties or that fruits 

 containing many seeds are larger than those containing but few. For 

 instance, in his pollination work with plums, MarshalP^ found that 

 many varieties mature a large precentage of seedless fruits. These 

 cannot be distinguished from those containing seeds by their size or any 

 other external characteristic. The same is true of fruits of the sweet 

 cherry. Furthermore it has been found that seed-bearing fruits of the 

 Japanese persimmon are uniformly smaller than seedless specimens 

 of the same varieties.'''' 



Composition and Quality. — Associated usually with differences in 

 the structure of fruits are variations in composition and quality. This 

 holds true for the structural changes associated with varying seed number, 

 and indeed the differences in composition are often greater than would 

 be expected from observation of the variations in structure. Table 8 

 shows the sugar content and acidity of seedless and normal pears and 

 Table 9 shows differences in composition between caprified and un- 

 caprified figs of several varieties. The difference in acidity between 

 the seedless and seed-containing pears is striking and is sufficient to 

 make a considerable variation in quality. Though the distinctions 

 between the caprified and the uncaprified figs are on the whole less 

 prominent they are great enough to be of commercial importance in 

 such varieties as the Dottato. There are differences also in color of 

 flesh between caprified and uncaprified figs of the same variety. ^^^ 



Perhaps the most striking dissimilarities in composition and quality 

 between seedless and seed-bearing fruits are found in certain varieties 

 of the kaki or Japanese persimmon. Zengi, Hyakume and certain other- 

 sorts are always solid, dark fleshed when they have a good supply of 



