March, 1928] 



AGRICULTURAL EXPERIMENTS 192' 



9 



POLLINATION OF McINTOSH AND BALDWIN APPLES 



With the greatl}^ increased production of Mcintosh apples in New 

 Hampshire the problem of pollination is exceedingly important, since 

 this variety has shown many indications of poor set due to lack of fer- 

 tilization of the blossoms. 



Work on this project was begun by L. P. Latimer in 1927, and, in 

 spite of the handicap of continuous rain during the blooming period, 

 has yielded significant results. 



Cross pollination was conducted on a screened Mcintosh tree and 

 a bagged Baldwin tree. These experiments were supplemented with 

 counts of set of fruit under field conditions on Mcintosh trees inter- 

 planted with different possible poUenizcrs. 



Pollination of Mcintosh 



One entire Mcintosh tree was en- 

 closed in a wire screen cage to exclude 

 bees and other insects which are known 

 to transfer pollen. All flowers that 

 were open weie hantl-pollinated on 

 certain dates; others were left as checks 

 to determine if there was any self- 

 fertilization in Mcintosh floAvers. On 

 the average, four flowcis were hand- 

 pollinated in each cluster. Every 

 flower in an individual cluster received 

 the same variety of pollen. Different 

 clusters on the same shoot and even 

 on the same spur were pollinated with 

 different varieties. 

 The results show that in 1927 Mcintosh was practically self-sterile and 

 Wagener and Delicious were the most reliable pollenizers. Baldwin 

 proved to be the poorest poUenizer for Mcintosh of the varieties tested. 

 The other varieties, Wealthy, Gravenstein, Delicious and Red Astrachan, 

 gave fairly satisf actor}' results. 



In the case of Delicious and Wagener pollen there was little loss of 

 fruit after Julj^ 7, and no significant loss in the number of clusters re- 

 taining at least one fruit. Where Astrachan was used, little more than 

 half the fruit counted on July 7 remained on the tree at maturity, Sep- 

 tember 9. The kind of pollen seemed to have no significant influence 

 on the size of the fruit developed, although the Astrachan-pollinated 

 fruit was consistently largest. 



The results of normal set of fruit in orchards open to insect polHnation 

 also showed the Wagener and Delicious the best pollenizers for Mcintosh. 



Good bloom is not enough. Mcintosh 



trees were found self-sterile in the 



Station's experiments. 



Pollination of Baldwin 



Hand pollination by the bagging method was performed on one Bald- 

 win tree using three pollen varieties: Delicious, Wealthy and Graven- 

 stein. The most satisfactory set of fruit was obtained with Delicious 

 pollen. (Hatch Fund.) 



