NORTHERN GREAT PLAINS FIELD STATION, 1913-1922 oe 
would be crosses if the varieties were self-sterile, and about half 
would probably be crosses if the varieties were self-fertile. This 
- method was not found practicable, however, as poor stands were 
obtained, and tender varieties died. There would also probably be 
some difficulty in handling the bees. 
Crossing by hand in the field has been carried on in a limited way, 
but there is generally so much other work to do when it must be done 
that little time is available for doing it. 
By far the greater part of the hand-crossing here has been done 
under glass in the greenhouse. Several hundred trees are growing in 
pots and tubs, and these are moved from their winter quarters in the 
root cellar to the greenhouse early in February. Most of the crossing 
is done in March, and the trees are kept in the greenhouse until the 
fruit is harvested. In this way it is possible to grow many varieties 
for breeding work that would not endure the climate outside. 
Breeding work has been carried on with a number of different fruits, 
but apples and plums have received the most attention. In addition 
to these two fruits, work is now being carried on with cherries, grapes, 
and small fruits. 
In the following paragraphs the character of the breeding or selec- 
tion work that has been done with each of the fruits is briefly outlined: 
Almonds.—A few almonds were grown in pots, and an attempt was made to 
cross them with Amygdalus nana, Prunus tomentosa, and P. besseyi. No fruits were 
obtained. Almonds have been discarded. 
Apples.—A large number of Wealthy and other apple and crab-apple seedlings 
have been planted in the testing blocks for selection purposes. Some of the 
Wealthy seedlings have started to bear, and most of these have decided crab-apple 
characteristics. A few selections have been made for further trial. Seedlings 
of a number of species of Pyrus and Malus are also being grown for selection 
purposes. A large part of the hand-crossing work with fruits has been with 
apples and crab apples. About 50 different varieties have been used. Pyrus 
baccata has been used to a large extent as a hardy parent. None of the seedlings 
have yet borne fruit. 
Apricots—Chinese and Russian apricot seedlings have been grown in the 
seedling-selection blocks and some selections for ornamental purposes made. 
They bloom very early and are liable to be damaged by frost. The trees are semi- 
hardy. Some of the common varieties of apricots were potted and crossed with 
the Chinese apricot (Prunus armeniaca) and the P. americana varieties of 
plums. But few seeds were produced from these crosses, and none of the seed- 
lings has borne fruit. No further breeding work is being done with apricots. 
Blackberries and dewberries—A few plants were potted, but no crosses were 
obtained. The potted plants have been discarded. 
Buffalo berries—Several thousand buffalo-berry seedlings have been set out 
for selection purposes. Variation has not been marked, and no selections have 
been made. Some apparently thornless buffaloberries were located in the wild 
in 1916, dug up, and transplanted to the station grounds. These plants failed 
to live, however, and no further effort has been made to locate thornless buffalo 
berries. There is some doubt as to whether these thornless specimens were 
Lepargyrea argentea or L. canadensis. A few buffalo berries were potted for inside 
crossing, but no seeds were obtained by this method. These trees have been 
destroyed. 
Cherries.—Sour and sweet varieties of cherries have been potted, and attempts 
have been made to cross them with pin cherries, sand cherries, Prunus tomentosa, 
chokecherries, and P. maacki. Crosses have not been secured from the last two 
fruits. Plants obtained from the other combinations have not yet reached a 
bearing age. 
Several hundred Prunus pennsylvanica seedlings have borne fruit, but although 
some show marked variation none have appeared good enough to be worthy of 
propagation. 
Several thousand Prunus besseyi seedlings have been grown, and this hardy 
native fruit shows a very decided response to cultivatic .. Variations in the 
