Fruit setting in apples depends on a pollination that gives a compatible 

 fertilhat'wu. The flowers are perfect, they produce much viable pollen, and 

 the}' are fully self- and close-pollinating. Yet some varieties are decidedly 

 self-fruitless because the pollen fails to function in starting seed and fruit 

 development. The pollen will, however, function in certain cross-fertiliza- 

 tions. 



The flowers shown above are, from left to right, of Mcintosh (self- 

 fruitless), Baldwin (somewhat self-fruitful) and Wealthy (highly self- 

 fruitful). There is nothing in the appearance of the flowers which 

 indicates the differences in self-fertility. 



Below shows a fruit spur of Mcintosh that had been self-pollinated but 

 on which no fruits set in contrast to a neighboring spur whose flowers were 

 cross-pollinated and on which fruit has set. 



A solid block planting of any self-incompatible variety of apple, or of any 

 other clonal variety of fruit with this type of sterility, does not afford 

 chance for cross-pollination; all the plants are merely branches from one 

 plant. Such varieties should be interplanted with others which bloom at 

 the same time and which are compatible in cross-fertilization. Here the 

 fruit grower's problem is to provide for a pollination that is compatible. 



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