76 Maine Agricultural Experiment Station. 1920. 



fairly fertile and produce fruit. Crosses, Stayman x Doucin 

 and Stayman x Gravenstein are sterile but the cross Gravenstein 

 x Doucin is fertile. These facts make it clear that because a 

 cross between two varieties (a x b) is sterile it is no guarantee 

 that the reciprocal cross (b x a) will be sterile. Further if the 

 •cross of two given varieties (a x b) is sterile and the cross of 

 two varieties including one of the given varieties (a x c) is 

 sterile it is apparently equally possible for the two different va- 

 rieties entering into the cross (b x c) to be compatible or in- 

 compatible. 



The varieties which are particularly fertile when crossed 

 are of especial interest to the man who desires to plant a com- 

 mercial orchard or to increase the bearing ability of one already 

 in existence by top working certain of the trees. Those crosses 

 which are marked with the three pluses (-j — \--\-) in table 4 

 should prove heavy bearers when planted together. Such or- 

 chards should be planted with the female parent, indicated in 

 the first column, as the predominating tree in the block. 



Among the leading varieties in Maine which should form 

 desirable combinations for commercial work are Baldwin with 

 the Golden Russett for the pollen parent; Ben Davis with Mcin- 

 tosh Red, Northern Spy, Opalescent or Wealthy for pollen par- 

 ent ; Golden Russett with Ben Davis for the pollinator. Esopus 

 can be planted with Ben Davis and Jonathan. Newton crosses 

 well with any of the common pollen varieties Grimes Golden, 

 Jonathan, Ben Davis or Spitzenburg. The relative compatibil- 

 ity of the other varieties may be seen by consulting the lists. 



The work of Alderman* makes it clear that the differences 

 in the yield of the fruit in self and in cross pollinated orchards 

 occupies about the same relations as are shown in the hand self 

 pollinations of table 2 and the hand cross pollinations of table 

 4. In this experiment a Rome Beauty* orchard that had been 

 bearing only moderate crops was cross pollinated by bringing 

 in branches of other varieties and allowing the bees to work 

 over these other varieties at the same time that they worked 

 over the Rome Beautv. A suitable control was made with an- 



♦Alderman, W. H., 1917. Experimental Work on Self-sterility of 

 the Apple. In Proc. Amer. Soc. for Hort. Sci. p. 94-101. 



*The Rome Beauty as will be seen in table 2 is nearly if not quite 

 .self-sterile. 



