DETERMINING NEED OF CROSS-POLLINATION 397 



dance of pollen available at the proper time. This is not true, 

 however, of a few varieties. Certain of the Winesap group of 

 apples, such as Stayman Winesap, Arkansas (Mammoth Black 

 Twig) , and Winesap, are intersterile for all practical purposes. 

 These varieties are thus not only self-unfruitful, but cross- 

 unfruitful also, and it is necessary to plant other varieties with 

 them such as Delicious, Jonathan, Grimes Golden, or Yellow 

 Transparent, if satisfactory crops are to be had. 



Although the pollen of the Grimes Golden is usually excel- 

 lent to use as a pollenizer, still, when it is applied to Arkansas 

 (Mammoth Black Twig) pistils, practically no fruit results. 

 Growers should consult their experiment-station officials and 

 secure the latest information relative to the cross-compatibility 

 of the varieties which they wish to plant. 



Poor Pollenizers. The results of experiments in various 

 parts of the country indicate that certain varieties make very 

 poor pollenizers. Stayman Winesap, Arkansas, and Winesap 

 pollen appears to be defective and germinates very poorly un- 

 der controlled conditions. As a result, these varieties should 

 not be relied upon to fertilize any of the other varieties. Like- 

 wise the pollen of Baldwin, Rhode Island Greening, Graven- 

 stein, Ohio Nonpareil, and Nero usually germinates poorly and 

 causes poor sets of fruit when used on other varieties. Fruit 

 growers should thus avoid these varieties when selecting a 

 pollenizer. 



Good Pollenizers, Some varieties seem to be unusually 

 good pollenizers and generally cause excellent sets of fruit. 

 In this group are found: 



Cortland Red June 

 Delicious Rome Beauty 

 Golden Delicious Steele Red 

 Grimes Golden (except for the Wagener 

 Arkansas variety) Wealthy- 

 Jonathan Winter Banana 

 Mcintosh Yellow Transparent 

 Northern Spy York Imperial 



