86 



INTERNATIONAL CONGRESS OP VITICULTURE 



A decrease of the difference in the time of ripening between early and 

 late varieties in the hotter localities is shown by comparing the dates for 

 Salton with those for Napa, as indicated by the vertical dashes. In the 

 former the interval between the dashes represents 20 days, in the latter 43 

 days. This corresponds very closely with the observed facts. 



That the conclusions of Angot do not apply exactly to California is shown 

 by data obtained by the California Experiment Station from experiments 

 carried out in Fresno and Yolo counties in 1913 and 1914. 



The starting of the buds of the raisin Muscat occurs in both of these 

 regions on the average about the middle of March. The mean temperature 

 for March at Fresno is 54.9 F. (12.7 C) and at Davis, Yolo County, 56.2 F. 

 (13.5 C.). This indicates that the mean daily temperature necessary to start 

 the buds in these regions is from four to five degrees higher than Angot's 

 9 C. 



The seasonal sum of heat necessary to ripen the grapes will depend on 

 the degree of maturity chosen. The most favorable degrees for shipping 

 grapes, for dry wine grapes and for raisin grapes represents three different 

 stages of maturity. Whichever of these we chose, however, it appears that 

 Angot's estimates are too low for the great interior valley of California. 

 This is clearly indicated by the following table, which represents three sets 

 of tests of ripening Muscat grapes, two in the San Joaquin Valley and one 

 in the Sacramento. The data given are the date of gathering and the Balling 

 degree and seasonal sum of heat to that date. The sum is reckoned from 

 March 15, the average date of the starting of the buds. 



Seasonal Sum of Heat for Muscat. 

 Kearney, Fresno County, 1914. Mean for Year, 17.6 

 Date of Gathering. Bal. 



Aug. 12 18.6 



Aug. 19 20.2 



Aug. 26 21.8 



Sept. 3 23.6 



Sept. 9 24.0 



Sept. 16 23.8 



Sept. 23 26.5 



Sum above 9 C. 

 from March 15, 1915. 

 1858 

 1983 

 2109 

 2231 

 2360 

 2486 

 2612 



Kearney, Fresno County, 1913. Mean for Year, 17.6 



Aug. 17 

 Aug. 23 

 Aug. 30 

 Sept. 8 

 Sept. 16 



21.0 

 23.9 

 25.5 

 26.8 



28.8 



Davis, Yolo County, 1914. 

 Aug. 26 21.4 



Sept. 2 25.8 



Sept. 8 26.1 



Sept. 16 26.5 



Sept. 23 28,7 



1917 

 2034 

 2170 

 2317 

 2443 



Mean for Year, 15.1 

 1549 

 1612 

 1677 

 1764 

 1841 



