538 Report of the Horticulturist of the 



IS THE METHOD OF TESTING FOR SELF-FERTILITY 

 BY COVERING THE CLUSTERS A RELIABLE ONE? 



The reliability of the method of testing the self-fertility of a 

 variety by covering its blossoms during the blooming period and 

 thus excluding pollen from other flowers, has been questioned by 

 some on the ground that the conditions within the covering may 

 be very different from those outside and especially that the ex- 

 clusion of winds and insects prevents pollination. 1 These ob- 

 jections will be considered here only so far as they concern the 

 work with grapes. 



Perhaps the best reply which can now be offered to these ob- 

 jections is the statement that out of 169 cultivated varieties of the 

 grape which have been tested here by this method 103 produce on 

 the average marketable clusters when the blossoms are covered. 

 As one illustration out of many that might be given on this point, 

 the record of Diamond is presented. In 1892, 2 clusters of this 

 variety in one of the Station vineyards were bagged during the 

 entire blossoming period. Two perfect clusters of fruit developed. 

 In 1897, 15 clusters of the same variety were likewise covered in a 

 vineyard near Penn Yan and 18 clusters in a vineyard near Pranch- 

 port. Each covered cluster developed into a perfect cluster of 

 fruit. Plate LII from a photograph of self-sterilized clusters of 

 Duchess and Diamond, covered during the blooming period ac- 

 cording to the method under discussion, shows how perfectly the 

 covered clusters of self-fertile varieties may develop. Even with 

 those varieties which show some variableness in the degree of self- 

 fertility under differences of environment, the results with the 

 same variety have generally been quite similar in the different 

 tests. 



Attention should be called to the fact that every one of the 103 

 self-fertile varieties cited above has flowers with long stamens. 

 If these varieties were able to become successfully self-pollinated 



1 Proc. Amer. Pom. Soc, 1897: 94. See also Fletcher, S. W. Reprint from 

 Proc. N. J. State Hort. Soc, 1899 : 12-14. 



