-,
I
t
£
On
iORCI NG 3TRAT BERRIES UNDER GLASS
Subnitte
to the
OREGON AGRICULTURAL COLLEGE
In Partial Fulfillment of the Requirements
For the Degree of
MASTER
O
SCIENCE
in
SCHOOL OF AGRICULTURE
Eucenia Somers
APPIOVED
Redacted for privacy
Professor of
eTn charge of Major
Redacted for privacy
Head of Department of
-
Redacted for privacy
Dean of School of
Chairman, Comnittee on Graduate Students
and Advanced Deprees
ILl TRODTJ C TIOLl
For a number of years, considerable interest in
strawberries as a greenhouse crop ha
b
been manifested
florists and others who produced out of season crops.
During the latter part of the nineteenth century several
articles appeared in the agricultural journals upon this
subject.
Most of them, however, were vague and contain-
ed little information as to methods of culture.
In 1897 Cornell University published a bulletin
entitled "Strawberries Under Glass."
This described
the cultural methods used. in the greenhouses at that
station.
In 1905 another bulletin was issued by Cor-
nell on "Forcing of Strawberries," which discusses the
varieties best adapted for forcing.
It describes an
experiment in which one hundred thirteen varieties
were tried out :ln the
roerxhouse.
Of these varieties
but three, the Marshall, Glen :iary, and President, were
found to be satisfactory for forcinc under glass.
This
bulletin also discusses econorry in handling plants,
optimum
temperature during forcing period, length of
tine required to mature a crop of strawberries, and the
control of the red spider.
After the publication of the søoid Cornell bulletin very little appeared In print regarding Strawberry
Porcine until 1917 when a bulletin was issued by the
Colorado Experiment Station.
This described an experi-
meht in which nine varieties were tried out, of these,
two, the Marshall and Glen Mary were recommended as
satisfactory.
and yoin
The relative merits of year old plants
plants were inve;iated.
were found to
The yo1nn plants
produce a heavier yi1d and larger
berries.
Cultural methods and fertilizers were also discussed bat no check plots were mentioned and apparent-
ly all plants received the same treatment and were
given the same kinds and amounts of fertilizers.
The
main experiment seemed to be that of testing out
varieties.
OBJECT OF PRESENT EERIUiT
As Strawberry
or cing had not been tried on the
Pacific coast and as it offered possibilities as a
profitable greenhouse crop an experiment was planned
in the fall of 1919, the objects
fwh:ich were---
1. To determine which varieties of those commonly grown in Oregon were best adapted for forcing.
2. To investiate the possibilities of modifying cultural methods commonly used in Eastern States
without interfering with the success of the crop.
3. To determine the response of 'the different
varieties to a'pn1icatios of nitrate of soda.
4.
ages.
o compare the yield of plants of different
METHODS AND MATERIALS
Methods com
practiced in Eastern States and in
Colorado in forcing Strawberries.
At Cornell Experiment Station and at the Colorado
Exeriment
Station plants for forcing were obtained in
the followirw manner:-
Small pots filled with rich soil were pluned along
rows of virgin plants, that is, plants which had. never
borne a crop of fruit. Runners from these plants were
led over the pots and fastened there until they had taken
root.
ed.
Only the first and strongest runners were selectAfter they were well rooted
taken to a
er pots.
potting shed where
the
pots were lifted and
they were shifted into
larg-
In the first Cornell experiment several shifts
were rade, but in the second experiment the plants were
shifted directly into fruitin
potS.
At the Colorado
Station the runners were rooted in five inch rots and
allowed to remain in
these until Auust when they were
lifted from the bed, shifted
into seven inch
pots, and
plunced into sand in the cold frame.
At Cornell the plants were also plunged into a cold
frame in coal cinders.
They were watered well once, then
Lowed to become dry.
Later they were watered as needec7
il the roots filled the iots, when water was again
h held
to
encorage t.e formatiofl of a large crown.
The plants were left in the cold frames until January
when they were gradually thawed out and moved into the
The temperature was increased until at
greenhouse.
blossoming time it was about 65 degrees F.
During
pollenation and ripening the temperature was kept at'
70 degrees P.
The conclusions drawn by those in charge of the
experiments was that:
1. The Marshall, Glen Mary, and President were
the best varieties for forcing.
2. A resting period of about three months was
necessary.
3. A slow starting of the plants
ormittod a
stronger development of the root svstem.
4. New crowns were preferable to old ones as
they
roduce a heavier yield and larger and better
berries.
METHODS USED IN PEESENT EXPEETMENT
As the experiments at Cornell and at the
Colorado
Experiment Stations were conducted with potted plants
the preparation of which involved considerable time
and expense, it seemed desirable to devise sore methods
which would eliminate the pots and the preliminary handling of the plants.
As this experiment was not planned until late in
September no potted plants which had been
in the field could be obtained as checks.
rooted in pots
Young sets
were purchased from the nurser: and were potted in slx
inch pots November 10th 1919.
frames until January 1st. 1020.
They were kept in cold
In conducting the ex-
perirrient these were regarded as checks.
To discover the possibility of reducing the expense
of early handlimr of the plants four varieties of straw-
berries were lifted in the field, January 1st 190 and
brought directly into the greenhouse.
ost of these were
planted in the bed, being set one foot apart each way.
o test their yield in pots eleven Oregon plants and five
Progressives were planted in six inch pots.
Every care
was used in handling these to avoid injurin
the roots or
in any way disturbl rig the ballcdf earth siirroundng them.
At this time the potted plants in the cold frares
were moved into the greenhouse and the check pots were
placed on a shelf directl:T above the heating pipes.
Others
that had received the same previous treatment were removed
from the pots and set in the bed for comparison with those
in the pots.
Six months old plants were found to be "best in New
York, but it seemed reasonable yearling plants which would
normally bear their first o:'op the following season, would
prove nrofitable when forced.
Such plants wee brought in
January let. 1920 and at the same time well grown sets were
lifted and brought in for comparison.
To determine the response of the
iferert varieties
of strawberry to nitrogen the viants in each variety vere
divided into two parts, one of which recei'ed. nitrogen
while the other did not.
LATERIALS JS.LD I i EXJ?IENT
The varieties of strawberries which are successful
comrercially east of the Rocky Mts, have not proveô
profitable on the Pacific Coast, therefore new varieties
have sprunw up which, while productive in the Western
states, are not satisfactory in the eastern part of
the co'intry.
In planning this experiment it was first
intended to compare varieties which were recommended
for forcing in the east with local varieties which,
while known to be snccessfu.l in the field, had never
been triec out in the greenhouse.
However, obtaining
good healthy o lints of the eastern va'ieties proved
to be difficult.
Fifty Marshall plants were purchased
from the nursery but they arrived in such povr condition that they could not he used.
Five plants were
pthted and used as checks, the rest were excluded from
the exDeriment.
It was then decided to use only western varieties
arid to coiipare them wIth each other as to which most
nearly aDproached the ideal forcing berry of the east
as well as which was best adapted to local forcing
corn are
conditions.
In order to/the forcing possibilities of
n varieties the characteristics of the vanen are described below
VARIETI3 CHOSEII
Oregon or Admiral Dewey Strawberry originated near
It is a cross
Salem, Oregon, with Mr. A.F. Hofstadtler.
between the Marshall and Jessie and is perfect flowering
and medium to early as to season.
The Fruit is variable
as to size and of good qal1ty but a poor keeper.
Magoon orinated as a chance seedlin
of V.J. Magoon near
large and vigorous.
medium earl;.
Portland,
in the garden
The plant is very
Oregon.
The flowers are perfeot and open
The fruit is variable in shape and size
but usually is quite large, flesh is dark red and rather
soft.
Marshall is an eastern variety which has proved
succesaf all as a forcing crop but not suocessfall as a field
In Oreon it has proved satisfactory in a few local-
cr01).
itles.
It is a mid season, soft, but productive variety.
Proressive originated in Oregon and belongs to the
ever beaTing type of strawberry.
continuously during the
In the field it bears
late sumrer and fall.
It would
Jnder greenhouse
be termed a very late season variety.
cOnditions, it produced a number of blossoms during Jan-
uary, but the stamens did not mature and as no pollen was
time,
obtainable from other sources, at that
The main crop did not materialize until
no frujts set.
too late to be of
value as a Porcing variety.
Gold lollar originated at 3pringbroo), Oregon.
plant is large, erect, and vigorous.
The
The crop inthe field
is early, but below medium in yeild.
in size and conical in shane.
The fruit is medium
This is the best early field
crop for Oregon.
Wilson originated near Albany, N.Y. many vears ao and
was very popular for over twenty years.
It is a pioneer
variety, growing best on soil that have not long been under
cultivation.
The plant is medium in size, viror, and yield.
The quality is below medium.
It is a good canning berry.
Superb is an overbearing variety which
is a poor plant ma3er.
yelids well but
Ettersburg 121 was originated by A.P. Etter, Briceland
California.
It is a "hybird of the wild Alpine crossed with
the Cape Mendocino Beach strawberry."
The plant is large
and very prodnictive but the fruit is below medium in size
although of good quality.
This variety produces better on
dry soils than it does on the more moists and fertile sthils
as in the latter case it produces only foliage and new plants.
DETAILED DI SCiJSSION OF EXPERIll1iT
The six months old plants which were ordered. from the
nursery arrived flovember 10, 1919 and were potted immediately.
The Gold Dollar plants were large and vigoro;s with good root
systems.
Twenty three of them were potted of which sixteen
were later selected for forcing in the greenhouse.
The Superb
plants were not so vigorous as the Gold Dollar but thirty were
iotted,.
The root systems were good but the leaves were black-
ened and moldy and there were blossoms or fruit on most of the
plants.
The Clark's Seedlin's and
arshal1s were so sal1 that
they were not potted but were placed in flats until they began to .row.
1ive of the larger Clark's Seedlings were pott-
ed. and treated like the other varieties but were not considered as rart of the experiment.
All of the rlants which were potted November lOtli, 1919
were placed in the cold frame until anury 1st, 1920 when
they were moved Into the greenhouse.
While in the cold frames
they receLved little care except that they were watered Occasionally.
During 'december the cold frames were buried under
the snow, which protected the plants during the zero weather.
Fifteen of the 3uperbs were removed from the pots and set in
the bed; the other fifteen were left In the pots and wore placed on the sill piats of the
reenhose just above theheating
pipes.
The six pots of IJarsha1l
plate.
Five Clark Seed.lins were also potted and set in the
same place.
wore also
et on the s:il1
The Cold Dollar plants were removed from the rots
and set in the bed.
December 30, 1919 Mnroon plants were broNghi in from the
field. and set in beds.
These were lifted with a large ball of
earth around their roots and every care was taken to prevent
disturbing the roots in any way.
Owing to the previous cold
weather which had killed most of the fo1i.e the ae of the
ants was difficult to ascertain but thirty plants were selected which seemed to be yearlings and nine runners were also
brought in.
Of these, six were quite 1are and had apparent -
ly rooted early in the season while three were sia1l.
The following day Oregon and Progressive plants were
obtained from the farm of Mr. Ed. Felton,as with the Maoons
the age of the Oregons was not easy to determine but fifteen plants were selected which had larger root systems
than the others and were probably yearlings.
runners were brought in at the same time.
Twenty-five
They were large
and seemed to have been rooted early in the season.
fifteen yearling plants and fifteen
set in the bed.
The
tbe runners were
Eleven runners were potted and set on
the sll pinte.
Pour yearling Progressive plants were set in the bed.
These had very large crowns and well developed root systems.
Twenty-four runners were also set in the bed.
They were
quite small and the soil had been washed from their roots.
Two runners were obtained which had been lifted with a
lare ball of earth around their roots;
in the bed.
these were placed
Five young plants were potted and set on the
sill pate.
Six yearling plants of the Ettorsburg 121 variety
were lifted in the field and brought into the greenhouse
Decerber 23, 1919.
They were very large and vigoro'is.
On
January 1, 1920 fourteen young pants of this variety were
planted in the bed.
Mr. Polton had obtained these plants
from a nursery during the fall and had "healed them in" until time to plant them.
They had no soil on their roots
when planted in the bed in the greenhouse.
Al. ter all of the Oregon plants had been planted as
planned for the experiment a number of good plants were
They had been dug with
left.
a spade arid were rooted
in blocks of earth about one foot in diameter.
At first
sight each block appeared to be one large plant bt;t upon
investigation proved to consist of from three to five
Five such blocks of earth with their plants
young plants.
were set in the bed without disturbing the roots of the
plants.
These were to be compared with the young Oregon
plants which were planted one foot apart each way.
TIATMENT OF PLJiT$
R11
EXPERIMHT
During the first two weeks after the plants were plac-
ed in the greenhouse the temperature was kept between 55
degrees and 60 degrees F. After January 16, the temperature was raised to 60 degrees F.
Between February 1st.
and April 1st it was kert between 65 and 70
degrees F. and
after that time at 75 derees F.
The first application, of nitrate was given January 25th,
after that date applications were given twice each week until Larch 6th.
Then no more was applied until April 7th.
when one application was given.
the time the
Io more was anpiled during
experiment was being conducted.
In all
about
12T0 grans of nitrate of soda were used during the forcing
period.
The plants were given all of the water they required
except at blooming time when water was withheld. somewhat
to a:id in pollenation.
None of the varieties except the Ettersburg 121 showed any tendency to produce runners.
The young Ettersburg
121 plants produced many runners and very little fruit,
only a few of these runners were removed.
The yearling
Ettersburg 121 produced a few runners which were cit off
at once.
RE $TJLT S
Observations on Progress of Plants.
On January 17, 1920 foliage had begun to grow on all
varieties except the iCagoons.
Ettersburg 121 and the Suerb.
It was most abundant on the
By January 30th the Etters-
burg 121 was showing a tendency to produce runners.
was starting to grow
n the Macoons.
Foliage
An Oregon plant had
one bud and the yearling, Progressives were full of buds,
none of which set fruit owing to absence of pollen.
On
February 5, a blossorr appeared on a Gold Dollar plant, the
next dar there were blossoms on the year1in
the Wilsons and the Oregons
.
Progressives,
Pebruary lth the first bloss-
om producing pollen was found; up to that date only pistillate flowers had appeared.
A weo1 later pollen was abund-
ant among the Oregons altho a few pistillate flowers were
still in evidence.
The blossons of the New Oregon, the Ma-
goou, the Gold Dollar arid the Wilson were large but those of
the Progressive were small and soon fell off.
Three of
the potted Oreons were in bloom on February 24th as were
also those which had been set in clumps.
March 2nd the Oregon and Magoon were in full bloom.
One Gold Dollar plant had several fruits set and another
had two fruits; the rest of the plants of that variety
showed no sins of blossoming.
At that tthe nitrate of
soda apDeared to have little effect upon any of the plants.
The writer became ill March 6th and was unable to care
for the plants until Arril 5, 1920.
plants
were
During this time the
watered and pollenated by Mr. A. E. Murneek.
On April 5th the writer found that much fruit was set on
the Maoons and Oregons.
fruits.
The Oregon pots had ten ripe
The Gold Dollars had five and a few blossoms, as
did also the Superbs and Progressives.
April 16th. there were
iany ripe fruits on the Oregons
and a few on the Magoons and Gold Dollars.
On this date
photographs were tal<en of the Oregons in pots, also of the
Superbs and Progressives.
The nitrate pots had more foliage
and smaller berries or none at all.
May 4th and 5th experi!,ent was closed and the number
of blossoms and berries were counted.
The Oregons kad near -
ly finished bearing but the Maroons had many green fruits
which were nearly full grown.
The Ettersburgs were just
beginning to ripen while the Progressives and Superbs were
white with flowers and buds.
A much larger yield might have
b'en obtained if the experiment could have ran longer bt the
later maturing varieties would not have ripened until the
earlier varieties growing in the open were placed on the
market.
A greenhouse crop, that matures so late in the
season, would not be
profitable, anyway.
The experiment
was closed in order that the data might be tabulated for
the thesis,
COLLEOTIOfl OF DATA
During the ripening period all ripe berries were
picked and weighed immediately.
ed in grams.
The weights were record-
All the plants were numbered and the product-
ion of each was recorded separately in
what percentage of the plants
order to discover
failed to set fruit, as
wel'.
as to observe any tendencies toward unusually high production in any partiôular plant.
Table 1, Giving Comparison of Varieties as to
total Production
Average
Average
Average No. Averae
weicht
weight
green fruits No.
of
ripe fru.its of
Variety per plant
per plant ripe fruit each
rer plant
fruit
Magoon
6.41
5.53
23.16
4.17
Oregoris
2.73
7.96
4o.52
5.93
pots 1.55
Ettersburg 21.50
Prog. bed 0.96
Prog. pots 1.33
9.45
41.42
4.28
5.75
16.36
2.84
1.33
3.10
2.33
2.66
9.31
3.4
SuDerb (1)
.94
.88
1.91
2.17
Superb (p)
G. Dollar
.41
1.12
2.54
2.16
.20
1.80
6.42
3.56
Wilson
1.35
2.43
5.03
2.0?
iarsha1l
1.50
.83
3.51
4.22
The Oregons produced the highest yield and the largest
berries.
The Maoon ranked second as to yield bit was about
one week later in ripening so that only about half the fruit
had matured when the experiment was closed.
The yearling
Ettersburg 121 set a heavy crop but were rather late for a
forcing crop and the berries too small to
e1l for the fancy
prices that greenhouse crops must demand in order to be profitable.
The Progressive and Superb are likewise too late
in fruiting to inake a rood forcing crop.
To be ideal, a
variety mast produce a large, uniform1r maturing crop of
bright colored berries of uniform size and shape.
The
Oregon most nearly approaches this ideal bat does not have
as attractive a flavor as does the Magoon.
The berries of
the Oregon are uniformly colored and attractive in appearance,.
as they ripen quite evenly and would be suitable to grow in
pots for banquets.
Table 11, Modifying Cultural Methods
Xeeping plants in pots during fruiting period
versus
planting them in beds at the beginning of the forcing period.
Average weight
Average per plant
Variety
Pipe Fruits
of each fruit
mt.ripe
frnit
Pots
7.96 9.45 46.52 41.52
Oregon
Progressive 1.12 2.66 2.68 9.31
1.91 2.54
.88 1.12
Superb
Totals 9.96 13.23 51.11 53.37
l7.034 17.79
Pots
Bed
Average 3.32 4.41
The plants in pots
were smaller except in
Bed
Bed
Pots
5.93
10.49
4.28
3.49
2.16
9.93
3.49
3.31
2.39
2.17
yielded heavier but the berries
the case of the Progressives.
Probably the results of the Progressives would have been
reversed if the
experiment had not been closed so soon
for the plants in the beds were full of blossoms when the
experiment closed.
The fruit in
because the pots were set on
heatin
did
the pots ripened earlier
the siliplate just above the
pines and the temperature averages higher than
over the bed.
plants in pots
it
Considering the expense of handling the
the increased yield
justify the practice.
i8
not sufficient to
Table 111, The Production Der square foot of space of
plants set one foot apart each way versus
plants set in elmps of three to eight plants
as dug with spade.
Each clump occupied two sq. feet of s'pace
ripe
fruits
wt. of
ripe fruit
wt. per fruit
Plants set one foot
apart each war
7.87
40.13
5.10
Clumps of plants
average per sq. ft.
11.20
53.75
4.78
Average producti on
of each plant in
clumps.
4.48
21.42
4.78
Wbile the average size of the berries is somewhat
lower the average production of the clumps per square
foot of space is sufficiently high to warrant farther
experimenting along this line.
ab1e lv,
Influence of nitrate of soda upon the
production of the different varieties
as to number of fruits and uniformity
of ripening.
Average # green
fruits per plant
Jntreated Nitrate
Var'letv
Average 7 ripe
ftuit per plant
7ntreated
Nitrate
11.80
3.20
6.20
6.33
4.00
1.87
8.07
7.87
.40
2.50
11.20
8.00
61.66
79.66
16.66
20.33
.58
1.66
1.50
1.00
rro,, (nots)
1.00
1.66
2.66
.66
Superb (bed)
.63
1.50
1.00
.66
Superb (pots)
.36
.50
1.54
.33
Gold Do11ar
.00
.50
2.11
1.33
Totals
80.43
93.05
50.94
48.51
8.94
10.34
5.66
Magoon
Oregon (bed)
Oregon (Dots)
Ettorsburg
Prog. (bed)
Average
5T
The untreated plants produced fewer berries.
They ripened their crop in the pots somewhat earlier
but in the beds the treated plants ripened their crop
first.
Eliminating the Ettersburg 121 plants, the
other eight varieties show an average yield of 5.89
berries for the untreated plots and 4.60 berries for
the nitrate plots.
Influence of nitrate of soda upon the
Table V,
production of each variety and upon the
average weight of the individual fruits.
Average weight
of ripe fruit
per plant
Tlntreated Nitrate
Variety
Average weight
of each strawberry
untreated Nitrate
26.93
23.33
4.34
3.80
Oregon(bed)52.8'7
40.13
6.55
5.10
0re.(pots)54.52
30.50
4.86
3.81
Ettersburg 37.63
66.56
2.64
3.27
4.13
1.97
2.75
1.97
Prog. (notb)8.33
10.30
3.12
3.86
Super(bed) 2.02
1.73
2.09
2.60
Superb(pots)3.33
.76
2.15
2.30
Cold Dollar 8.19
3.76
4.33
otal 198.02
178.04
32.83
29.54
19.78
3.65
3.18
Magoon
Pro.(bed)
Average 22.00
The production was greater for the untreated
than for the treated plants and the berries were
larger.
It was noticed however that the Oregons
in nots which had received nitrates wore setting
a new cro
o-
berries vhen the oxperient closed.
The untreated pots showed no sL'ns of producing
any more berries.
Only the Etersburg showed any rn
mar1ed increase In production due to nitrates. The
Progressives and. Supèrbsshow a slihtincrease in
the size of th
berries where nitrate was applied.
Influence of age of plants upon
Table Vi,
production.
Average wt.
er fruit
Average
ripe fr7its
Wt. of ripe
fruits
Yearling Young
Yearling Young Yearling Young
Variety
Llagoon
6.26
4.50
25.30
23.01
Oregon
8.07
7.87
52.89
40.13
Ettersbrgi8.5O
.28
D2.lO
1.35
3.39
ProRressive .25
Total 33.08
Average
1.25
14.15 131.52
8.27
1.50
3.54
32.88
4.03 5.32
6.55 5.10
2.82 3.65
5.00 2.26
68.78 18.40
17.19
lc.33
4.60 4.08
The production of the yerin plants of the Ettersburg 121 and 0reon was greater tiian that of the young
plants of the same variety. The average production of
all four varieties was also greater for the yearling
plants. The results seem to show that yearling plants
are very much more profitable than young plants even
raising them to their
second season is considered. The luzuriant foliage of
when the
additional expense of
the yearling Oreons caused some of the fruit to rot
while green.
This rotting also occured among the young
plants of this variety but to a srnalter
rotting occured among the
the potted Ore ens.
extent.
No
other varieties nor among
STJMIARY
1. The results of this experiment seem to show that
strawberries can be forced successfully under Western
Oregon conditions.
fruit of any
During
the early
spring
months fresh
kind is scarce and commands a fancy price.
Placing strawberries on the market at this time would be
opportune and little
trouble
should be experienced in
creating a demand for the crop.
2. Some varieties of strawberries which have originate
in Vestern Oregon, Washington and California lend
themselves well to Threing under glass.
3. The Ettersburg 121, the Progressive and the Superb
are late season varieties and, when forced, are too slow
in producing a crop to be profitable.
The first named
variety would set a heavy crop which might offset the increased cost of forcing if the berries were of good size.
Owing to the humid conditions in the greenhouse the tendency of Ettersbu.rg 121 is to produce luxuriant foliage
and the berries, while numerous, are too small to be
attractive.
4. Of all the varieties tried out the Oregon is the
most promising as a forcing variety.
It produced more
berries and larger berries than any other variety and the
crop ripened uniformly so that it could be marketed advantageously.
The berries are bright red and evenly color-
ed with no white tips.
They are attractive in ai'pearance
whether displayed in boxes or on the potted plants.
In
the latter case they shouid sell well for banquets as the
large red berries and luxuriant creen foliage are very
striking.
5. Except when raising potted plants for banquets,
the slight increase in yield from the potted plants would
not justify the expense of handlin
the plants in pots.
6. The application of nitrate of soda did not in-
crease the yield sufficiently to offset the expense of
the nitrate and the labor of apilying it.
7. In the case of the Ettersburg 121 and the Oregon
the production of the yearl1n
plants was enough greater
than that of the young plants to offset the expense of
raising the plants to that age before forcing them.
8. The data seems to show that large plants bro;ght
from the field with their roots undisturbed are better for
forcing but more
investigation is
needed along
this line.
ACKNOWLEDGL:ENTS
The writer wishes to express her appreciation for
assistance and suggestions given her by members of the
faculty in p1annin
and conducting this experiment.
Professor W.S. Broin helped plan the experiment and.
arranged for space in the greenhouse and cold frames.
ir. William A. Smart helped secure the plants and Mr.
A. E. Murneok earect for them during the writes illness.
Dr. E.. iiirvey offered many valuable suestions and
to use
permitted the vriter/space in the research laboratory
for investiiation of the hstolocical phases of the
problem and the use of scales in the laboratory while
collectinp the data.
LITERATURE CITED
Vallea, W.D.
"Sterility in the Strawberry."
Journal of Aprioaltiiral
esearch. Volumn Xli No. 10
(1918)
Gardner, V.R.
"Strawberry Varieties in Oregon."
Second Bieja1
pp 50 to 94.
roi Pest and Horticultural
Report (115) 0.A.C. Experiment Station.
E t t e r,
ibert P.
terbtrg Strawberries."
1917 catalog
)"Strawberries Under Glass."
Hnnn
Bailey
Cornell Experiment Station bulletin No. 134 (1897)
Hunn C.E.
"Porcing of Strawberries" Cornell Experi-
ment Station bulletin No. 231, 1905.
Kinnison F.I. "Strawberry Foriong" Colorado RxDeriment Station bulletin No. 222 (1917)
EXPLANATION OP PLATES
Plate 1.
no nitrate.
ripe.
Three of the potted Oregons which received
The berries are large and many of them are
There are no blossoms left on April 16, 1920 when
the photo was taken.
Plate 2.
Three potted Oregons which received nitrate during
forcing period.
ripe.
The fruit is not large and. few berries are
The plants are still blossoming.
Photo was taken
April 16, 1920.
Plate 3.
Two Progressive plants one of which received nit-
rate and the other was untreated.
while the former did not.
The latter produced berries
These were photographed the same
day as the Oregons, and. illustrate the difference between
varieties quite well.
Plate 4.
Two Superb plants one of which received nitrate
while the other dId. not.
the others were.
Photo taken the same day that
--:
0
Plate 1.
Plate 2.
Plate 3.
Plate 4.