436 The Journal 
“In the improvement of any fruit,” 
says W. R. Ballard of the Maryland 
Experiment Station,” ‘‘an intimate 
knowledge of varieties is essential to 
intelligent effort. Such information 
should include not only the adapta- 
bility of varieties to climatic conditions, 
habit of growth, season, productive- 
ness, character and quality of fruit, 
but should also include as far as possible 
information concerning disease resist- 
ance and historical data in regard to 
parentage. The great majority of varie- 
ties grown in this country are un- 
doubtedly of hybrid origin. This is 
due to the promiscuous cross-pollination 
carried on by bees and other insects. 
This fact makes the value of a variety 
for breeding purposes somewhat prob- 
lematical since many characters show 
up in the progeny which cannot readily 
be detected inthe parents. This hybrid 
nature, however, works to the advan- 
tage of the breeder of orchard fruits for 
wide variation occurs in the first 
generation, so that he does not have to 
wait until the second generation for 
such results, as would be the case were 
he working with pure strains. Investi- 
gations here and at other stations indi- 
cate that the greatest improvement is 
to be secured by using for breeding 
purposes only the best of the varieties 
now in existence. Only occasionaly is 
it necessary to depart from this rule 
in order to utilize some particular 
character of an otherwise inferior 
variety. 
“Since pollination can be done only 
during a comparatively short blooming 
period, it 1s essential to be thoroughly 
prepared for work when the time comes. 
There is more or less variation in the 
time of blossoming of different varieties, 
although in abnormal seasons all varie- 
ties have been known to bloom at about 
the same time. Advantage can often 
be taken of this variation by using the 
early bloomers as the male parent. 
This enables one to collect pollen in 
workable quantitites before the buds of 
expected by crossing varieties that have already been improved. 
of Heredity 
the later varieties are ready to be 
pollinated. Weather conditions are also 
more likely to be favorable for pollinat- 
ing work at this later period. 
MAKING POLLINATIONS 
‘““Normally the anthers burst and the 
pollen is shed shortly after the blossom 
opens. This usually takes place early 
in the day. In cross-pollination it was 
formerly customary to break off re- 
cently opened blossoms and brush the 
stigmas of the emasculated buds with 
the opening anthers. There was always 
danger in this method that bees or 
other insects had already visited the 
flowers leaving a deposit of foreign 
pollen in the blossom used for pollinat- 
ing. Where the purpose was simply 
to get variation without regard to 
parentage, this method worked very 
well in a small way, but where a study 
is to be made of the laws of inheritance 
more accurate methods must’ be 
followed. 
‘““A simple method used by the author 
to insure a good supply of pollen is to 
gather a number of buds which are just 
ready to open but not far enough ad- 
vanced to allow the entrance of insects. 
This would usually be about a day 
before they would normally open. By 
grasping the petals between thumb and 
forefinger, they can easily be rubbed off, 
together with anthers. These are then 
collected on a newspaper and after the 
loose petals and other waste materials © 
have been sifted out, the anthers are 
transferred to glass dishes (petrie dishes 
are excellent for this purpose) and placed 
in a moderately warm dry atmosphere. 
The anthers will soon burst open re- 
leasing the pollen grains. When the 
pollen becomes dry it is protected from 
moisture until needed. Handled in this 
way it may be kept for several days, 
although it is always advisable to use it 
as soon after being collected as con- 
venient. Should doubt arise as to it 
viability, a test of its germinating power 
is made by placing a small quantity of 
The wild species are of value 
mainly as stocks for grafting, a Chinese species known as Pyrus davidiana having proved par- 
ticularly valuable by its hardiness and vigor. 
2 Ballard, W. R., Methods and Problems in Pear and Apple Breeding. 
Maryland Agri- 
cultural Experiment Station, Bulletin No. 196, College Park, Md., April, 1916. 
