New YorK AGRICULTURAL EXPERIMENT STATION. 365 
INTRODUCTION. 
Many kinds of cultivated grapes have been found to be more 
or less self-sterile. They either utterly fail to fruit or produce 
imperfect clusters when the vines are planted by themselves; 
but they may fruit abundantly when grown near enough to 
other varieties to secure cross-pollination. This is demonstrated 
in previously reported investigations which are summarized in 
Bulletin No. 157.1 From other experiments it appears that the 
degree of self-fertility of a variety is a very good indication of 
its efficiency in fertilizing self-sterile kinds of grapes. So far as 
they have been tried, the self-sterile kinds are usually no more 
capable of fertilizing other self-sterile kinds than they are of set- 
ting fruit themselves, but when pollen of strongly self-fertile 
kinds has been used on the self-sterile grapes an abundance of 
perfect fruit has generally developed. In such cases it is evident 
that the lack of fertility cannot be attributed to imperfection of 
the pistils. If these were imperfect no fruit would develop from 
them under any circumstances. The experiments just referred 
to are fully set forth in Bulletin No. 169.2, Observations made 
in 1892 and in various succeeding years show that self-sterile 
varieties do produce pollen? The question then arises: Is such 
pollen altogether impotent? Is it as incapable of causing the 
fertilization of self-fertile as it is of self-sterile grapes? The 
experiments reported on the following pages were undertaken 
to get more information on this subject. The work was carried 
on with the efficient help of Mr. Heinrich Hasselbring and Mr. 
O. M. Taylor in 1901. Mr. Taylor also assisted in the work of 
1902. At the same time the influence on self-fertility of check- 
ing the flow of sap, either by girdling or by twisting and bending 
the cane between the trunk of the vine and the fruit buds, was 
investigated. The report of this work is given in Part II of this 
bulletin. 
1Reprinted in Annual Report of this Station for 1898: 518-563. 
2Reprinted in Annual Report of this Station for 1899: 361-397. 
3Notes on Self-Pollination of the Grape. Proc. A.A.A.S. 1892. Gard. ana For., 1892: 
451-452. Annual Reports of this Station 1892: 597-606, and 1894: 642-643; also other 
unpublished observations. 
