Oxford Democrat., 1920-06-01
Fertility and steriIlty In Apples.

the difficulties experienced at Highmoor
Farm % regards the apple yield In the
large solid blocks of Ben Davis trees
And in studies ss there reported 1t was
shown that not only ls the Ben Davis self.
sterile but that most varieties of apples are
dependent upon pollen from other .varie.
ties of trees to insurea good set of fruit
This opened up to the Maine Agricul-
tural Experiment Station the whole ques.
ton OF procedure to obtain sufficient pol.
len from other varieties to fertilize the
blossoms on this block of 1900 trees OF
the one variety at Highmoor Farm. To
top-work some OF the trees was OF course
the most practicable method. But tina,
led to the questions of how frequent
must pollen furnishing trees be placed,
must they be scattered or can they be In.
troduced in rows, and finally is there
any choice in varieties.
The last question was the first and i'm
portant one to be settled. For,y-three
different kinds of crosses were tried iD
testing to see II there is such thing as
cross sterility. About half of the CROSSES
tried proved to be compatible and fruit
forming. Only two crosses Duchess as
female and Baldwin pollen and Ben Davis
female and Hurlbert Sweet pollen) abso-
lutely failed to produce fruit. But there
were great differences In the compatible
ity of the others. The results of the tri-
ais with the varieties at Highmoor Farm
led to the study of the literature and the
tabulation of the crossing records that
have been made and published In the
Gkoko nt1k af
attempts at crosses with 243 varieties, 81
crosses failed to produce fruit. That is,
it was found that three, quarters of the
varieties were cross fertile as against
only one.third of varieties that were un-
der any condition tried found to be self
fertile. These facts argue strongly for
the necessity Of arranging to have cross
pollination in orchards And also for
the necessity OF wise choosing of the pol |
linating varieties.
A study made by Alderman makes 1t |
clear that the differences In the yield of |
fruit in self.pollinsted and in cross-pol |
linated orchards occupies about the same |
relations as has been found to be the
case in self-pollination and in cross. .polli-
nation made by hand. In this expert
ment Rome Beauty orchard that had |
been bearing only moderate crops was
,ross- -pollinated by bringing in branches
of other varieties while In full bloom and |
the bees to work over these
,tber varieties at the same time they
worked over the Rome Beauty trees. A
suitable control was made by another
block OF Rome Beauty trees at q suitable
distance. The cross-fertilized Rome
Beauty trees yielded double the amount
# fruit of the others. The trial was re.
,eated the following year with the same
differences found between the cross pol
mated and the other portion of the Or
hard.
The varieties which are particularly
ertile when crossed are of especial inter-
at to the man who desires to plant q
commercial orchard or to increase the
'earing ability of one already planted by
op-working certain of the trees. These
vill be given In detail 10 Q bulletin that
as been prepared by the Maine Station,
'ut which will not be received from the
rinter in time for this years top-work.
ng. To any one desiring to top. work
n orchard this spring the station will
lady make suggestions of the pollen
aren't on receipt of information of the
ariety to be crossed.
Among the leading varieties In Maine
7hich should form desirable combina-
ions are the following: The female pa
ent ia first named and the pollen bear
NJ parent second in each group. Bald.
,in crossed with Golden Russet; Ben
)avis with Mcintosh Red, Northern Spy,
)palescent or Wealthy; Golden Russet
nth Ben Davis; Esopus with Ben Davis
r Jonathan. |,
As to the number of trees it has been
ound that the pollen bearing trees may
70 reduced to as low as 3 per cent, one in
wenty. But II, as is best for harvesting,
! is desired to grow the pollinsting trees
D rows and not scattered trees through
be orchard the pollinating rows should
70 about every fifth. If It is desired to
row both kinds In about equal amount
hey can be in alternate blocks OF four
r five rows of each variety. In the case
I orchards already planted the above
Ian can also be followed by grating the
pollenizer as in the plan just
While waiting for these pol
enizsrs to grow to bearing age some re-
ef may be had by cutting large branches
4 good pollinating varieties and while in
loom place them in pals Of water sus-
'ended from the tree limbs. Not much
eliance can be placed upon the wind for
ross -pollnation. Insects, wild and cul-
ivated, are the best agencies for trans
'orting pollen from one variety to
mother. Bees are profitable on this &C.
cunt in an orchard even though they
nay not make honey enough to feed
themselves during the year.
CHAs. D. WOODS, Director.