June, 1933] Pollination and Fruit Setting in the Apple 35 



other varieties have never shown any definite evidence of self-fruitfulness 

 in the eastern states and should never be planted in very large blocks or in 

 the total absence of other varieties. 



As a pollenizer Baldwin is a complete failure. This is indicated in Table 

 Vn which shows that with none of our leading New England varieties has 

 Baldwin given satisfactory results as a pollenizer. Rhode Island Greening 

 has behaved in a similar way except that it has been found to poUenize 

 Wagener satisfactorily. The same may be said for Gravenstein. The poor 

 pollenizing ability of these three varieties is probably due to the poor germi- 

 nating ability of their pollen and to the large percentage of abnormal pollen 

 grains which they develop as a result of their unusual genetical make-up. 



The other varieties are generally efficient pollenizers, with these excep- 

 tions : Cortland has not yet proven a satisfactory pollenizer for Graven- 

 stein. Delicious has failed to show evidence of satisfactorily pollenizing 

 Golden Delicious or Rhode Island Greening. Mcintosh has not satisfac- 

 torily pollenized Delicious, Rhode Island Greening or Wealthy. Northern 

 Spy has not yet caused a satisfactory set of fruit on Delicious or Rhode 

 Island Greening and Wealthy has failed as a pollenizer for Fameuse and 

 Rhode Island Greening. Oldenburg and Wagener seem to be outstanding 

 as good pollenizers for all varieties tested. 



In addition to the crosses shown in Table VII Oldenburg has also been 

 found to pollenize Melba and Lobo well. Melba is self-unfruitful. 



With relation to the ability of certain varieties to be successfully pollen- 

 ized by others, the following may be said : It has been difficult to find many 

 satisfactory pollenizers for Delicious, Golden DeHcious and Rhode Island 

 Greening. 



Of those shown in Table VII, Cortland, Oldenburg, Wagener and 

 Wealthy are the only varieties that will pollenize Delicious satisfactorily 

 beyond any doubt. Golden Delicious seems to be pollenized satisfactorily 

 by Northern Spy but not by Baldwin or Delicious. Rhode Island Greening 

 is pollenized well by Cortland and Oldenburg. 



Finding suitable pollenizers for the remaining varieties has seemed less 

 difficult. 



In addition to failure to respond to pollination by Gravenstein and Rhode 

 Island Greening and Baldwin, Delicious has failed to give a satisfactory 

 set when pollenized by Mcintosh ; Gravenstein by Cortland. 



Wagener is unusual in that Gravenstein and Rhode Island Greening have 

 proven satisfactory pollenizers for this variety while Mcintosh has failed. 



Certain variety mixtures are not to be considered in relation to their 

 pollenizing qualities because of the small chance of the period of bloom 

 coinciding under New Hampshire conditions. Such relationship exists 

 between Golden Delicious and Gravenstein, Golden Delicious and Mcin- 

 tosh, Gravenstein and Northern Spy, and Mcintosh and Northern Spy. 



Fortunately, among a few varieties interfertility exists. The following 

 lists indicate first, cases where two varieties may be planted together and 

 each will satisfactorily pollenize the other ; and, second, cases in which two 

 varieties are inter-sterile and neither will pollinate the other. 



To illustrate inter-fertility of two varieties, it may be seen from Table 

 VII that in many cases where two varieties are concerned, each pollenizes 

 the other satisfactorily. Thus one may have a Cortland orchard inter- 



