BREEDING 427 



is the shape ; but most of the increased size in crosses of orchard 

 fruits probably arises from the fact that the pollen is acceptable. 



Setting aside the consideration of size resulting from crossing, 

 we still wish to know whether changes in shape, color, quality, 

 and season of ripening of the fruit will result from crossing by 

 pollen. A few instances of such changes have been noticed in the 

 case of some plants in which the seed is the principal part of the 

 fruit ; for example, corn, peas, and beans. With fruits in which 

 the seed is surrounded by a fleshy pulp, as in the apple, it is still 

 a matter of dispute whether the pulp is at all changed. Most men 

 have formed their theories about the immediate influence of pollen 

 from observation rather than from experimentation. It does not 

 necessarily follow that " sweet and sour " apples are due to cross- 

 pollination, nor that the russet on Greening apples that grew on the 

 side of the tree next a Roxbury was produced by the influence of 

 the Roxbury pollen. 



Most of the changes in fruit which are attributed to the influence 

 of cross-pollination are due to variation. Every bud on a tree is 

 different in some way from ever)' other bud on that tree, and 

 may develop unusual characters according to the conditions under 

 which it grows. 



