June, 1933] Pollination and Fruit Sktting in thk Apple 19 



In 1927, 1929 and 1930 all flowers in an individual cluster were pollinated 

 with the same variety of pollen hut various spurs on the same branch were 

 often pollenized with different varieties. 



Pollen was applied in 1931 and 1932 only to lateral flowers in the cluster, 

 all terminals being removed. Another feature which dift'ered from previous 

 experiments, and which it was thought would give more uniform results, 

 was the pollination of four flowers in every cluster used. This procedure 

 was adopted on the basis of results presented in previous publications by 

 the author (1, 2). The reasons for choosing these methods in ]ireference 

 to the spur-unit plan are also discussed in these papers. 



Screen cages were kept over the trees throughout the season. But when 

 cheese cloth was used, it was removed from the frames as soon as it was 

 certain that the last flower to open was past the receptive stage. All condi- 

 tions were therefore maintained as near to those of an open orchard as 

 possible in 1930, 1931 and 1932. 



Counts of set were made both before and after the June drop. The June 

 drop was light during 1931, perhaps due to an unusually large amount of 

 rainy weather during the early growing period. 



A second or late drop, unusual in New Hampshire, occurred in August — 

 about a month after the June drop. This feature is discussed in another 

 paper (2). 



At the time of bloom in 1927 weather conditions were cool and for the 

 most part rainy. In 1928 pollination experiments were not carried on ex- 

 tensively because of almost continuous daily downpours of rain. In 1929 

 the first period of bloom was accompanied by mild days and cold nights, 

 followed by an unusually cold, cloudy, misty period succeeded by pleasant 

 weather. In 1930 the weather was unusually warm and dry throughout the 

 blossom period and was by far the most favorable for bee flight. 



Weather conditions were unsually favorable for fruit setting in 1931. 

 Bright sunshine and high temperature prevailed w'ith little rain during the 

 period of full bloom. The least favorable feature was the rapidity with 

 which the trees came into full bloom and the shortness of the period when 

 stigmas w-ere receptive. 



Fine weather prevailed at pollination time in 1932. 



Table I shows the results of five seasons' tests on Mcintosh pollination 

 in New Hampshire with relation to the per cent of blossoming spurs setting 

 fruit after hand pollination. 



The data show that for all practical purposes, Mcintosh may be consid- 

 ered self-unfruitful. When Mcintosh pollen is brushed onto the stigmas 

 (hand pollination) a slightly higher set of fruit is to be expected with this 

 variety than where the flowers are left undisturbed except by wind or rain 

 (check). 



Many previous workers suggest that when 30 per cent of the blossoming 

 spurs develop fruit to maturity on full-bearing Mcintosh trees, this is rep- 

 resentative of a satisfactory crop from a commercial point of view. If these 

 individuals are correct, then Mcintosh is deciflcdly in need of pollenizers. 

 In the five years of experiment, the highest set was 11.8 per cent. A set of 



(1) L P. Latimer. Pollination studies with the Mcintosh apple in \cw Hampshire. Proc. 



Amer. Soc. Hort. Sci. (27) 1930. 



(2) L. P. Latimer. Further observations on factors afifecting fruit setting of the Mcintosh apple 



in New Hampshire. Proc. Amer. Soc. Hort. Sci. (28) 1931. 



