254 The Commercial Apple Industry 



winds prevent the activity of bees. In very hot weather 

 high winds may so entirely dry up the fluid secreted by the 

 stigma as to make germination of the pollen-grains impos- 

 sible, (f ) Spraying in full bloom. Injury is caused and 

 pollination is sometimes prevented if trees are sprayed in 

 full bloom before pollination has taken place. 



The above discussion outlines some of the influences 

 affecting the set of fruit. It now becomes important to 

 consider mixed varieties with relation to cross-pollination. 

 It is generally recognized that too much emphasis was 

 formerly placed on the advisability of mixing varieties in 

 order to aid in pollination. As a result, many orchards 

 were set with mixed varieties when two or three well 

 selected kinds would have provided for cross-pollination 

 and would have been a much more desirable arrangement 

 from a commercial standpoint. The orchardist too often 

 proceeded on the theory that if a few different varieties 

 were advisable as pollinizers, many were the more desir- 

 able. As a matter of fact, one variety which is a good 

 pollinizer may serve exactly as well as a score. The much 

 discussed secondary effects of pollination should not be 

 allowed too greatly to influence the planting of pollinizers. 

 The direct effects of crossing certain varieties have not been 

 established. Variations in the characteristics of different 

 apples are now more generally attributed to bud variation 

 than to cross-pollination. It is generally conceded that 

 flavor, quality or color of apples is not directly affected by 

 the cross-pollinating variety. 



This should in no way be construed as an argument 

 against cross-pollination, for in the case of the self-sterile 

 or partially self-sterile varieties it is absolutely essential. 

 Cross-pollination may effect the size of fruit and may 



