IOO THE PEARS OF NEW YORK 



Self-sterility and self-fertility are greatly influenced by the condition 

 under which a variety is grown. Thus, a variety is often self-sterile in 

 one locality and not in another. Occasionally Bartlett, usually nearly 

 or quite self-sterile, and other varieties as well, set fruit one season and 

 not the next. All pears, the Bartlett in particular, seem to have a greater 

 degree of self-sterility in eastern pear regions than on the Pacific slope. 

 In general, the better the adaptation of a variety to its environment the 

 better it sets fruit with its own pollen. It is obvious, therefore, that it 

 is not possible to give lists of self-sterile and self-fertile varieties. Such 

 lists can be made out only for regions and localities. Some varieties, 

 however, more often fail to set fruit because of self-sterility than others. 

 Among standard pears, Bartlett, Beurre d'Anjou, Beurre Clairgeau, Clapp 

 Favorite, Howell, Kieffer, Lawrence, Sheldon, and Winter Nelis appear to 

 be most often self-sterile. Beurre Bosc, Flemish Beauty, and Seckcl are 

 usually self-fertile. 



A self-sterile variety usually sets fruit when another variety is at hand 

 to supply pollen. Several considerations determine the selection of varieties 

 to interplant. Thus, the two varieties must blossom at the same time if 

 cross-pollination is to be effective. The table on pages 88 to 90 shows the 

 sorts that bloom at the same time, or nearly enough so to make cross- 

 pollination possible. Under normal conditions, the blooming time of 

 varieties overlaps sufficiently for cross-pollination excepting those that 

 bloom very early and very late. If the table is used for regions much to 

 the north or to the south of this Station, allowance must be made for a 

 shorter blooming period the farther north; a longer one the farther south. 

 That varieties of pears have sexual affinities is another consideration that 

 merits some attention. That is, one variety will fertilize another sort 

 very well, while pollen from a third may not be at all acceptable. 

 " Affinities " can be determined only by hand crossing. Probably the 

 importance of affinities is over-rated. The distance between varieties set 

 for cross-pollination must not be too great — not more than two or three 

 rows apart. For convenience in harvesting, varieties should be selected in 

 relation to ripening. Only commercial varieties should be interplanted, as 

 the wastage is too great if comparatively worthless sorts are set to fertilize 

 a standard commercial variety. 



Some disadvantages attend the setting of mixed orchards of pears, 

 and these must be weighed and overcome as far as possible. There are 

 many current statements to the effect that all varieties, whether self-sterile 



