WV.“ SEEH-FERTEIRTEY’Or THE’*GRALEe 
S. A. Breacu. 
SUMMARY. 
Cultivated American grapes show remarkable differences in the 
degree of self-fertility of different varieties. Many of them fruit 
perfectly of themselves. Others form no fruit when cross polli- 
nation from other varieties is prevented. Most varieties are found 
between these two extremes, being neither fully self-fertile nor 
completely self-sterile. | 
With many varieties the degree of self-fertility is not an un- 
changeable characteristic, even when the vines appear to be in 
a normally productive condition; but varies under differences of 
environment. Many other varieties which have been under ob- 
servation show practically no variation in this respect. Usually 
when any variation in self-fertility is observed with a variety it 
is confined within rather narrow limits. In exceptional cases rather 
wide variations are seen. 
Investigations to determine the degree of self-fertility of a 
variety should be made with vines in a normally productive con- 
dition because variations in the amount of fruit which sets may 
be due to an unproductive condition of a portion or all of the vine. 
It is desirable, also, that a large number of clusters be tested for 
each variety and that the tests be made in more than one locality 
and in more than one season. 
One hundred and sixty-nine cultivated varieties were included 
in these investigations. They are classified, according to the de 
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* Reprint of Bulletin No. 157. 
