June, 1933 J Pollination and Fruit Setting in the Apple 



6? 



Self-fniitf Illness. Self- fruit fulness occurs where fruit setting is satis- 

 factory from the application of a given variety of pollen to a flower of the 

 same variety. The presence of bees helps to increase the set in such 

 varieties by increasing the transfer of pollen. Many large blocks in New- 

 Hampshire consist entirely of Baldwin and always set heavy crops. Hand- 

 pollination tests confirm these observations. The set on self-fruitful sorts 

 may generally be further increased through cross-pollination, but in some 

 cases this may not be desirable. Too heavy a set may be detrimental. 



H the fruit of pollenizers does not have a high market value, self-fruitful 

 sorts are economical. 



Effect of Location: 



The effect of locality on pollination and fruit setting has already been 

 mentioned. Variations in the results of certain varieties as pollenizers for 

 others, or in the self-fruitfulness of certain varieties, can be noted only 

 when wide areas are considered. Mcintosh is self-unfruitful to a high 

 degree throughout New England, for example, but self-fruitful to a much 

 greater degree in Washington (1) and Montana (2). Baldwin which seems 

 self-fruitful in New Hampshire to the satisfaction of commercial growers 

 has been found by Hewlett (3) to be doubtfully so in Ohio. 



Differences in the self-fruitfulness of these varieties, on the other hand, 

 does not vary appreciably within a distance of several hundred miles, as 

 indicated by a comparison of New Hampshire experiences with experi- 

 ments in Massachusetts (4) and New York (5). The same is indicated in 

 the case of Mcintosh self-fruitfulness when comparing the results of Mon- 

 tana (2) and Washington (1). Nevertheless, Mcintosh and other varieties 

 nearly always set heavier crops in some sections of New England than in 

 others. 



Mcintosh orchards located on hillsides and hilltops in some areas of New 

 Hampshire are noted for their heavy set of fruit, which is generally better 

 than in valley orchards. Even when pollenizers are reduced to a minimum 

 at the higher elevations, the set of fruit is sometimes superior to that at 

 lower elevations where better provision has been made for pollination. 



Observations of Mcintosh planted in blocks have sometimes led the 

 grower to believe that in these orchards the Mcintosh was self-fruitful. 

 Generally in such cases, however, a few odd varieties may be discovered 

 in adjacent fields w^hich would easily be a source of pollen. Frequently a 

 grower will overlook this fact, the usual feeling being that only common 

 cultivated sorts can pollinate cultivated varieties. This assumption is wrong 

 in most cases, for it is more often the fact that such odd varieties or seed- 

 lings make exceptionally good pollenizers. 



A location at a small elevation may often be more favorable for fruit 

 setting, because of the greater freedom from frost at blossom and fruit- 



(1) O. M. Morris. .Studies in upple pollination. Wash. Agr. Exp. Sta. Bull. 1(53. (1921) 



(2) F. M. Harrington and W. E. Pollinger. Pollination of the Mcintosh apple. Mont. Agr. 



Exp. Sta. Bull. 2.56. (1932) 



(3) F. &'. Howlett. Apple pollination studies in Ohio. Ohio Agr. Exp. Sta. Bull. 404. (1927) 



(4) F. C. Sears. The pollination problem in Massachusetts apple orchards. Rpt. Mass. Fruit 



Growers Assn. (1928) 



(5) L. H. MacDaniels and A. J. Heinicke. Pollination and other factors affecting the set of 



fruit with special reference to the apple. Cornell Agr. Exp. Sta. Bull. 497 (1929) 



