TESTING CRAPE VARIETIES IX THE VTNIFERA REGIONS. 27 
The term "congeniality" as used in this discussion is limited to 
the relation of vine varieties to the resistant stocks upon which they 
are grafted. To discriminate properly between adaptability and 
congeniality and then to determine the congeniality, it is necessary 
to know the behavior of the resistant varieties as well as the Vinif- 
era varieties on their own roots. If we have grafted vines of which 
both the stock and the scion varieties are known to be suited to the 
soil and climatic conditions and they do not respond, we know that 
congeniality is lacking. 
The adaptability of varieties can be closely forecasted, but their 
congeniality must be determined by actual tests. Without knowl- 
edge of its adaptability to existing conditions, the extent to which 
differences in the behavior of a variety grafted on different stocks 
are due to congeniality or to adaptability is impossible of determi- 
nation. 4 
Saccharine and acid determinations of the fruit from grafted vines 
have been made for a number of years with a view to ascertain 
whether the quality of the fruit is influenced by the stock upon which 
the vine is grafted. (See PL X.) Such determinations contrasted 
with the same season's growth ratings of the same vines indicate a 
close correspondence between these important chemical constituents 
of the fruit and the congeniality of grafts and stocks as determined 
by observations, and they afford a useful check on the congeniality 
ratings. 
Similar growth ratings of a variety grafted on various stocks are 
found to be accompanied by fairly definite percentages of sugar and 
acid. Under like conditions of growth the sweetness and the acidity 
of the fruit, as well as its time of ripening, are materially influenced 
by the congeniality of the scion and stock. The saccharine and acid 
contents are two of the leading considerations in the money value of 
the fruit. 
In determining the relative congeniality of vine varieties on diverse 
resistant stocks, these and the relative quantity of fruit produced, 
the difference in time of ripening, the relative healthf illness and com- 
parative durability of varieties on different resistant stocks, and the 
relative amount of wood produced are some of the considerations 
that appear most important. 
BEHAVIOR OF GRAPES GRAFTED AND ON THEIR OWN ROOTS. 
In Table VII, column 1 gives (1) the variety name, and indented 
under it (2) the name of the resistant stock on which it is grafted, or 
if the variety is on its own roots the fact is so stated. Column 2 
shows the experiment vineyard in which the growth was tested, use 
being made of the following abbreviations: C for Chico, Cx for Col- 
fax, F for Fresno, G for Geyserville, Gi for Guasti, L for Lodi, Li for 
Livermore, M for Mountain View, O for Oakville, S for Sonoma, St 
for Stockton. Column 3 shows the year in which the stock was 
