June, 1933J Pollination and Fruit Setting in the Apple 25 



Another method of indicating the efficiency of certain varieties of pollen 

 in causing fruit to set on Mcintosh is evident from Table I\' which records 

 the average numl)er of fruits per cluster. The data show that rarely more 

 than one fruit develops on a Mcintosh cluster pollinated by Baldwin, Grav- 

 enstein, Mcintosh or Red Gravenstein. It has been shown previously 

 (Table I) that these varieties are also incapable of causing a good set of 

 fruit on the tree as a whole where Mcintosh is cross pollinated. 



Fameuse heads the list from the viewpoint of the number of fruits per 

 cluster. Usually about two per cluster were obtained where Mcintosh was 

 pollinated by this variety (Table IV). It has already been noted that 

 Fameuse is one of the leaders in causing a high percentage of fruit spurs 

 of Mcintosh to develop fruit as a result of cross-pollination. Wagener is a 

 close rival in this respect. 



Pollination of Cortland: 



The methods used in Cortland pollination experiments w^ere similar to 

 those followed with Mcintosh. Cheese-cloth cages only were used to ex- 

 clude insects. 



Cortland as indicated in Table V seems at times to be partially self-fruit- 

 ful, especially when hand or bee pollinated. In both cases the set was 

 heavier than when the flowers were left entirely to the efTects of the wind 

 and rain. 



Baldwin was found to be a poorer pollenizer for Cortland than Cortland 

 itself. A fair set of fruit was obtained when Delicious pollen was used but 

 was not as satisfactory as that effected by several other varieties. The high- 

 est set of Cortland fruit was generally obtained when Mcintosh or Wag- 

 ener was used as pollenizer. Gravenstein produced a satisfactory set of 

 fruit in two of the three years, and Red Gravenstein in 1932. The data 

 show that in 1932, however, the set with Gravenstein and Red Gravenstein 

 as pollenizers, was no improvement over that obtained with Cortland pollen 

 itself. Lobo pollen does not seem to give a satisfactory set of fruit on Cort- 

 land. The most important finding is that Cortland and Mcintosh are cp&ss- 

 fruitful varieties. ' ^^^""^ 



Pollination of Delicious and Gravenstein: 



One year's results (1930) indicate that Delicious and Gravenstein are 

 nearly self-unfruitful. In neither case was fruitfulness increased by the 

 use of Baldwin pollen. Although the use of Gravenstein, Wealthy and 

 Wagener resulted in a set of fruit on 32.6 per cent, 30 per cent and 26.8 

 per cent, respectively, of the blossoming spurs on Delicious, this might be 

 considered unsatisfactory from a commercial viewpoint, as the tree used in 

 the experiment, although vigorous, was decidedly alternate in its bearing 

 habit. Mcintosh and Winter Banana as well as Red Astrachan might also 

 be considered in most seasons as unavailable for Delicious pollenizers be- 

 cause of the earliness of their blooming season as compared with Delicious. 

 (See Table V.) 



One year's results with Gravenstein indicate that Delicious would be a 

 satisfactory pollenizer, except that its late blooming habit fenders it uncer- 

 tain. The periods of bloom of Delicious and Gravenstein do not overlap 

 enough of the time to make availability of pollen dependable under field 

 conditions. (See Table V.) 



