New York Agricultural Experiment Station. 521 



subject of systematic investigation until the work by the writer 

 at this Station showed that self-sterility, either absolute or to a con- 

 siderable degree, is found with a large number of cultivated Ameri- 

 can grapes. 



METHODS OF INVESTIGATIONS. 



THE VINES. 



The vines which have been used in these investigations have 

 been generally thrifty, vigorous and in a. normally productive 

 condition. 



The Station vineyards, in which most of the work has been 

 clone, are on a fertile clay loam which favors a strong growth of 

 vine. Some weak kinds, like Rebecca, have not made a good 

 growth, but most of the varieties are probably stronger growers 

 here than they are on the average on land better suited for vine- 

 yard purposes and especially for developing high flavor in the 

 grape. 



Although the vines in these vineyards generally make good 

 growth, they are seldom too vigorous to yield well. Some idea of 

 the yield that may be expected from productive varieties on this 

 soil may be gained from the following statement of the annual 

 yield per vine of "Warden in a Station vineyard. 



Six "Worden vines planted in the fall of 1892 yielded their first 

 fruit in 1895, averaging about half a pound per vine. In 1896, 

 the fourth season after planting, the yield was 11.63 pounds; in 

 1897, 23.38 pounds; and in 1898, 18.31 pounds per vine. 



COVERING THE CLUSTERS. 



In testing a variety for self-sterility the clusters which have 

 been selected for the test are covered with paper bags before the 

 blossoms open. This excludes outside pollen so that if pollina- 

 tion takes place the pistil must either receive pollen from its own 

 blossom or from some other blossom in the same cluster. Ordinary 

 manila paper bags obtained from the grocer have been used, the 



