8 JOURNAL OF THE ROYAL HORTICULTURAL SOCIETY. 
CONTRIBUTIONS FROM THE WISLEY LABORATORY. 
XXXVII.— Pollination in Orchards (v.). 
Summary of Apple Pollination Investigations. 
By A. N. Rawes. 
That varying degrees of self -sterility exist among the many varieties 
of apples in cultivation has already been recorded in this Journal,* 
in a preliminary report on the investigations being made at Wisley 
into the problem of self-fruitfulness and self-sterility of varieties of 
this fruit. 
From many other sources also, particularly American, papers have 
been published relating to this phenomenon, and it is widely recognized 
as of the greatest economic importance to fruit-growers. 
It is now common knowledge that in growing many varieties, 
facilities must be provided which will ensure the suitable pollination 
of the blossoms if good settings of fruit are to be obtained, no matter 
whether the trees be grown in large areas for commercial purposes, or 
in the small orchard or private garden. 
This paper deals in the main with the economic bearing which the 
problem has upon the arrangement of the orchard or garden, and serves 
to summarize the work done at Wisley in this light since the publica- 
tion of the report referred to above. The results obtained and con- 
clusions which may be drawn should be of some value to prospective 
planters, and to growers in whose plantations adequate facilities for 
cross- pollination are lacking. 
In spite of research along many lines, all attempts to discover why 
certain varieties are unable, to set more than a very small percentage 
of their blossoms, or none at all, when dependent upon their own 
pollen for fertilization, have up to the present failed. Many interesting 
facts have been brought to light in the course of these investigations, 
but these may be conveniently withheld until the work is farther 
advanced. 
The report referred to was concerned solely with work carried 
on outdoors, upon trees growing near the Meteorological Station, 
and under conditions that made extensive and reliable experimental 
work difficult. 
For this reason the writer of the report advised caution in regard- 
ing the negative results obtained as conclusive evidence of sterility, 
since so many factors, other than that of lack of efficient pollination, 
were likely to prevent fruit setting. 
* Chittenden, F. J., " Pollination in Orchards" (iii.), Journal R.H.S. xxxix. 
p. 6i 5 . 
