New Yoke Agricultural Experiment Station. 545 



MAY VAEIETIES BE CLASSIFIED ON THE BASIS OF 



SELF-FERTILITY? 



In previous reports of this work classified lists of self-fertile, 

 imperfectly self-fertile and self-sterile grapes have been made for 

 the guidance of grape growers. The question now arises whether 

 the variation in the degree of self-fertility of some varieties is 

 sufficiently great to make such a classification of them unreliable. 

 An examination of the changes in the classification which have 

 been brought about by extending the experiments to more than 

 one location and into more than one season will throw some light 

 on this question. All of these discussions refer to normally pro- 

 ductive vines unless otherwise stated. Care must be taken to dis- 

 tinguish between variations in yield due to an unproductive con- 

 dition of a portion or all of the vine and that which is due to 

 self-sterile blossoms. 



Looking at the self -sterile lists it is found that Brighton, Eume- 

 lan, Lindley, Marion, Norwood and Woodruff have at one time 

 been classified as self-sterile. 1 In later tests they have produced 

 from one to several fruits. 



Similar changes have been made in the lists of perfectly self- 

 fertile sorts. The following varieties have produced none but per- 

 fect clusters from self-fertilized blossoms in some tests while in 

 others a portion or even all of the clusters have been somewhat 

 loose. Antoinette, Berckmans, Bertha, Cottage, Delaware, 

 Diana, Early Golden, Mabel, Moore Early, Niagara, Pocklington 

 Prentiss, Rutland, Worden. 



The following varieties, so far as tested, have produced none 

 but perfect clusters when the blossoms were covered: Ambrosia, 

 Columbia, Croton, Diamond, Etta, Herald, Hopkins, Janesville, 

 Lady Washington, Leavenworth, Lutie, Marvin Seedling White, 



1 It is doubtful whether the Hayes and Denison vines were in good con- 

 dition at the time the first tests were made in which they were self-sterile. In 

 later tests they produced clusters about half filled from self-fertilized blossoms. 

 With these exceptions the vines in the self-sterile lists have shown unvary- 

 ing self -sterility so far as tested. 



35 



