70 Maine Agricultural Experiment Station. 1920. 



Forty-three different kinds of crosses were tried in testing" 

 for any cross sterility which might exist between the different 

 varieties. Of these crosses 20 proved compatible and formed 

 fruit. Only two of the crosses tried more than 10 times failed 

 to set fruit. These two crosses were Duchess female x Baldwin 

 pollen and Ben Davis female x Hurlbert Sweet pollen. When 

 the cross was made the other way Baldwin female x Duchess 

 pollen and Hurlbert Sweet female x Ben Davis pollen the cross 

 was successful and fruit was matured. It is desirable, there- 

 fore, to leave those crosses which did not set fruit in abeyance 

 until such time as more data can be collected for them before 

 any definite conclusion is drawn on their cross sterility under 

 Maine conditions. 



Of those trees which proved fertile certain varieties stand 

 out as quite desirable for commercial plantings. Considering 

 the number of crosses made in conjunction with the amount of 

 fruit set Ben Davis pollen proved quite successful with Golden 

 Russett female ; Golden Russett pollen proved to set a high 

 percentage of the fruit when crossed with the Baldwin; Golden 

 Russett pollen crossed fairly well with the Ben Davis; Mcin- 

 tosh Red pollen proved very desirable for crossing on Ben Davis 

 female. The same was also true for the pollen of Northern 

 Spy, Opalescent, Crab and Wealthy when crossed with Ben 

 Davis. 



Table 4 gives the same data for the varieties which have 

 been tested for cross fertility as that given in table 2 for the 

 self sterile varieties. The data are presented for those which 

 are compatible and set fruit on crossing and those which did 

 not prove compatible and did not form fruit. The crosses 

 which are marked plus ( + ) or yes proved to set fruit on cross- 

 ing. Those marked minus ( — ) did not set fruit. After those 

 which did not set fruit is given the number of trials that were 

 made for the given cross. From these data some estimate may 

 be made of the probability that fruit might be set on a further 

 crossing of these same varieties. 



The percentage of fruit set or the degree of compatibility 

 of the cross is indicated where it is known by the number of 

 plus signs. The ± sign represents a very low percentage of 

 fruit set with only a few number of trials. The -f- sign shows 

 that a low percentage of fruit was set, the number of trials be- 



