SUMMER MEETING. 45 



Notes From the Field. 



BY B. T. GALLOWAY, WASHINGTON, D. C. 



Sterility of Pear and Apple Flowers as a factor influencing fruitfulness. 



lu the course of some investigations of pear blight carried on by 

 the Department of A.griculture, it was shown that when insects were 

 excluded from the flowers many varieties of both pears and apples 

 failed to set fruit. This discovery led to experiments which seemed 

 to clearly prove that most of our well-known varieties of pears and 

 apples are practically self-sterile ; in other words, to obtain a good 

 crop of Bartlett pears, for example, it is necessary for the flowers to 

 receive pollen from some other variety. A Bartlett pear flower fertil- 

 ized with its own pollen, if it develops into a fruit at all, will be so dif- 

 ferent from the typical form as to be scarcely recognizable. The 

 evidence at hand seems to clearly indicate that pollen from most of 

 the well-known varieties will fertilize the Bartlett flower and produce 

 typical Bartlett fruits. On the other hand, Bartlett pollen is thor- 

 oughly capable of fertilizing other varieties, such as Anjou, Winter 

 IS^eelis, etc., the result being in every case the production of typical 

 fruits of the kinds in question. 



These statements are not based on a few scattered experiments ; 

 on the contrary they are made after hundreds of tests, extending over 

 a period of nearly three years. The whole of the evidence at hand 

 resulting from this work may be briefly summarized as follows: 



( 1 ) The majority of the cultivated varieties of pears and apples 

 require cross-fertilization in order to bring about successful fruitage. 

 By cross-fertilization is meant the transfer of pollen from a different 

 horticultural variety, and not from a different individual of the same 

 variety. 



(2) Bees and other insects perform the work of cross-fertilizing. 



(3) The weather at the time of flowering has an important influ- 

 ence on the visits of bees and other insects, and through these upon 

 the setting of the fruit. 



Horticulturists will see at a glance the practical application of the 

 foregoing principles. No single variety known to be partially or 

 wholly self sterile should be planted in large blocks without introduc- 

 ing others known to be good fertilizers. Unquestionably the failure of 

 many orchards to fruit can be traced to this cause, and the remedy in 

 such cases is to introduce, either by top-grafting, budding or planting, 

 varieties known to be active fertilizers. Of coarse, judgment must be 



