FERTILIZING SELF-STERILE GRAPES.* 
S. A. Brac. 
SUMMARY. 
In Bulletin 157 were recorded the results of several seasons’ 
work in testing the self-fertility of the grape. Lists were given of 
grapes which were perfectly self-fertile, partially self-fertile or 
self-sterile and completely self-sterile. Many of our cultivated 
American grapes belong in the last two classes and require cross 
pollination for formation of perfect bunches. The work of 1899 
has been devoted to a study of the question whether some grapes 
are better than others for fertilizing the self-sterile kinds. 
Prevention of accidental cross-pollination was secured by en- 
closing in paper bags the selected bud clusters of both the variety 
to be pollinated and that furnishing the pollen. Cross-pollina- 
tion was effected by removing the pollinating cluster, when in 
blossom, from the parent vine and enclosing it with the cluster to 
be fertilized. ‘The clusters were sometimes brushed together be- 
fore enclosing, sometimes simply enclosed in the paper sacks and 
shaken, to distribute the pollen. 
Twelve nearly or quite self-sterile varieties were treated with 
pollen from one or more of twenty-four varieties ranging from 
perfectly self-fertile to self-sterile. The results are given in the 
body of the bulletin, both in detail and summarized. The use of 
self-sterile varieties as pollinizers for other self-sterile varieties 
resulted in failure. Self-sterile varieties fertilized with varieties 
not strongly self-fertile produced clusters varying in compactness 
about as did the bunches of the pollinating variety. Self-fertile 
sorts, with rare exceptions, gave good results when used as fertil- 
* Reprint of Bulletin No. 169. 
