160 The Principles of Fruit-growing 



Bees and insects appear to be the principal pollen 

 distributers. Climatic conditions influence, to a certain 

 degree, the relative blooming periods of the different kinds 

 of fruits. In frosty localities, varieties can be selected with 

 reference to their time of blooming, thus partially elimi- 

 nating the difficulty of a failure of fruit. We found that 

 pollen was capable of maintaining its viability for three- 

 weeks, provided it was not allowed to ferment. The length 

 of time different kinds of fruit remain in blossom at this 

 station are as follows: Apples thirteen days, pears eleven 

 days, and cherries ten days." 



In a conclusive study, Gardener has found that all 

 Oregon varieties of sweet cherries are self-sterile, although 

 in all cases the pollen germinates in nutrient solutions. 

 He also found that many varieties are inter-sterile; thus, 

 Bing, Lambert and Napoleon planted together with no 

 other variety are all sterile, although Black Republican 

 and Black Tartarian will fertilize each of them. Sour cher- 

 ries do not seem to be self-sterile so far as preliminary 

 studies in New York indicate. 



It is not yet known how constant in different regions 

 or under unlike conditions are the attributes of self-fertility 

 and self -sterility in varieties of fruits, or how much of the 

 barrenness of orchards may be due to impotency of pollen. 

 Some cases of barrenness attributed to this cause may be 

 due to other and unrecognized deficiencies. Some of it is 

 attributable to frost or wind at blooming time, to neglect 

 and other causes. It is certain, however, that impotency 

 or inefficiency of pollen is one of the prime factors in fruit 

 failures, and it should be taken into account in all orchard 

 plans by avoiding solid blocks of varieties. It is safer to 

 plant not more than five or six rows of one variety together 

 unless the variety is known to be abundantly self-fertile. 



