576 



FUNDAMENTALS OF FRUIT PRODUCTION 



succulent and melting, and differs so widely from the fruit of the other trees 

 that I have heard many gardeners, who were not acquainted with the 

 circumstances under which the fruit was produced, contend against the 

 identity of the variety. The buds were, however, taken from the same 

 tree. 



"I have also some reasons for believing that the quality of the fruit 

 of the peach tree is, in some cases at least, much deteriorated by the oper- 

 ation of the plum stock." 



In Grapes. — CurteP^ reported a difference in must from Pinot grapes 

 on their own roots and on Riparia roots. More careful studies in 1903 

 are recorded in Table 6. In his discussion Curtel stated that there were 

 differences according to the variety and the stock and that since the 

 amount of organic nitrogen was thought to explain the observed differ- 

 ences in susceptibility to wild yeasts the matter might assume considerable 

 practical importance. 



Table 6. — Analyses op Juice Extracted from Grapes 



{After Curtel*^) 

 (Parts in 1000) 



Pinot 



on 



Riparia 



Pinot 



Gamay 



on 

 Solonis 



Gamay 



on 



own roots 



Dextrose 



Levulose 



Total acidity 



Bitartrate of potassium 



Phosphoric acid 



Organic nitrogen 



Ash 



Tannin 



Coloring matter 



87.30 

 102 . 05 

 9.20 

 8.47 

 0.46 

 4.02 

 5.15 

 1.05 

 100.00 



81.07 

 98.05 

 8.54 

 8.51 

 0.61 

 3.17 

 5.45 

 1.85 

 126.00 



153 . 50 



10.43 

 9.41 



1.04 

 100.00 



158.70 



8.60 

 10.43 



1.10 

 106.00 



Bioletti compares grapes grown on certain stocks r^^ "The quahty 

 of the grapes was in nearly all cases, where a comparison was possible, 

 better on Riparia stock than on St. George. The grapes were larger and 

 sweeter. The higher sugar content was, moreover, usually accom- 

 panied by higher acidity, showing that the grapes were better developed." 

 Quantitative data are shown in Table 7. 



Husmann^^ uses sugar and acid determinations of grapes as a test of 

 the congeniality of the graft. Extensive determinations were made to 

 test the effects of various stocks on the quality of the fruit. "These 

 tests," Husmann states, "have yielded very interesting and suggestive 



